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This is to certify that the

thesis entitled

ECONOMIC ASSESSMENT OF COWPEA
GRAIN STORAGE TECHNOLOGIES:
A CASE STUDY OF NORTHERN CAMEROON

presented by

Mary Allison Schulz
has been accepted towards fulfillment
of the requirements for

, .
Master 3 degree in Agr1cultural
Economics

 

 

 

Rina ‘4 ‘BMTA—

Major professor

Date November 19, 1993

0-7 639 MS U is an Affirmative Action/Equal Opportunity Institution

 

 

UNNERSITY LIBRARIES

llllll\lllllllllllllllllll

3 1293 01022 1871

 

. LIBRARY
Michigan State
Unlverslty

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECONOMIC ASSESSMENT OF COWPEA GRAIN STORAGE TECHNOLOGIES:
A CASE STUDY OF NORTH CAMEROON

Mary Allison Schulz

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Agricultural Economics

1993

ABSTRACT

ECONOMIC ASSESSMENT OF COWPEA GRAIN STORAGE TECHNOLOGIES:
A CASE STUDY OF NORTHERN CAMEROON

by

Mary Allison Schulz

Scientists and policy makers have focused a great deal of attention on reducing
post-harvest food loses as part of the overall strategy for coping with possible future food
shortages in the developing world. Out of this concern several international and national
research institutions have conducted research to quantify the level and causes of on-farm
food grain storage losses. Inadequate storage facilities have been blamed for some of
the grain losses.

To address this issue, data were collected in northern Cameroon by a
Bean /COWpea CRSP research team. In addition, samples of stored COWpeaS were
collected from all interviewed households and assessed for storage damage.

Scientists at Purdue University and IRA (under the auspices of the Bean/Cowpea
CRSP) developed improved on-farm grain storage technology. The profitability of these
technologies was evaluated using benefit-cost analysis to assess their potential

attractiveness to different types of farmersn'traditional" and ”advanced”.

 

This thesis is dedicated to my parents, John and Valerie Schulz,

and my sisters, Karen, Bonna, Nancy and Debbie.

ACKNOWLEDGEMENTS

First, I would like to thank Dr. Richard Bernsten for serving as my major
professor and research advisor. His guidance and support were essential to the
successful completion of my graduate study. I would also like to thank the other
members of my thesis committee, Dr. Anne Ferguson, Dr. Russ Freed and Dr. Allen
Shapley.

Next, many thanks to the graduate students, support staff and faculty of the
Department of Agricultural Economics, Michigan State University. Each one of you
have helped make my years here enjoyable, challenging, rewarding and memorable.

I also wish to acknowledge the Bean/Cowpea CRSP, whose funding helped make
this research possible. And Jane Wolfson, for allowing me to use her Cameroon data.

Finally, I am especially thankful to Eric, for encouraging and supporting me

throughout this endeavor.

iv

TABLE OF CONTENTS

LIST OF TABLES .................................................. viii
LIST OF FIGURES .................................................. xi
KEY TO ACRONYMS ................................................ xii
CHAPTER 1 INTRODUCTION ........................................ 1
1.1 Problem Statement .......................................... 1

1.2 Objectives ................................................. 2

1.3 Hypotheses ................................................ 3

1.4 Thesis Organization ......................................... 3
CHAPTER 2 COWPEAS IN AFRICA ................................... 5
2.1 Overview of Cowpeas ........................................ 5

2.1.1 Cropping System ..................................... 5

2.1.2 Utilization of Cowpeas ................................ 6

2.2 Storage of Grains ........................................... 7

2.2.1 Damage vs Loss of Foodstuffs .......................... 8

2.2.2 Where Losses Are Incurred ........................... 10

2.2.3 Farm Level Storage Losses ............................ 10

2.3 Insect Pests cf Cowpeas ..................................... 13

2.4 Traditional Grain Storage Structures ............................ 15

2.5 Traditional Grain Storage Treatments ........................... 19

2.5.1 Various Ashes and Inert Dusts ......................... 19

2.5.2 Use of Plant Materials ............................... 19

2.5.3 Heat and Smoke .................................... 20

2.5.4 Natural Barriers and Resistant Varieties .................. 21

2.6 Breeding Improved CowPea Varieties ........................... 22

2.6.1 International Institute of Tropical Agriculture ............. 22

2.6.2 Bean/Cowpea Collaborative Research Support Program ..... 24

2.7 Grain Storage Technologies .................................. 24

2.7.1 Hermetic Storage and Silos ............................ 25

2.7.2 Insecticides ........................................ 26

2.7.3 Critique of ’Improved’ Grain Storage Technologies ......... 27

2.8 Effects of Storage on Nutritional Properties of Cowpeas ............ 27

2.9 Summary ............ 28
CHAPTER 3 COWPEAS IN NORTHERN CAMEROON ................... 29
3.1 Cowpea Production and Extension in Northern Cameroon ........... 29

3.1.1 Cowpea Consumption and Utilization .................... 33

3.1.2 Cowpea Research in Northern Cameroon ................. 34

3.2 The Bean/Cowpea CRSP/IRA Cameroon Project ................. 36

3.2.1 CRSP Storage Technologies ........................... 40

3.2.1.1 Storage in Ash .............................. 40

3.2.1.2 Triple Plastic Bags ........................... 42

V

vi

3.2.1.3 Solar Heater Technology ...................... 44
3.2.2 On-Farm Demonstration Results ....................... 46
3.3 Cowpea Producer Survey .................................... 49
3.3.1 Socioeconomic Characteristics ......................... 50
3.3.2 Farm Characteristics and Management Practices ........... 51
3.4 COWpea Farmer Categories and Characteristics ................... 54
3.5 Cowpea Storage ........................................... 55
3.5.1 The Storage Process ................................. 57
3.6 Farmer Classifications and Their Storage Process .................. 63
3.7 Farm-Level Storage Losses ................................... 64
3.7.1 Storage Losses and Farmers Field Practices ............... 67
3.7.2 Storage Losses and Storage Methods .................... 68
3.8 Economic Value of ”Lost Grain” ............................... 69
3 9 Summary ................................................. 70
CHAPTER 4 METHODOLOGY ...................................... 72
4.1 Introduction .............................................. 72
4.1.1 Economic Concepts Relevant to Benefit-Cost Analysis ....... 72
4.2 Benefit-Cost Approach ...................................... 78
4.2.1 Average Benefit-Cost ................................ 78
4.2.2 Marginal Benefit-Cost ................................ 79
4.2.3 Sensitivity Analysis .................................. 80
4.3 Factors Affecting Technology Adoption: Literature ................ 82
4.4 The Model ............................................... 88
4.5 Factors Affecting Cowpea Storage Technology Adoption: Cameroon
Situation ............................................... 88
4.6 Summary ................................................. 93
CHAPTER 5 RATE OF RETURN ANALYSIS OF ALTERNATIVE

GRAIN STORAGE TECHNOLOGIES ............... 94
5.1 General Approach .......................................... 94
5.1.1 Storage Technology Cost Stream ....................... 94
5.1.2 Storage Technology Benefit Stream ..................... 97
5.2 Farmers’ Utilization of On-Farm Storage ........................ 103
5.2.1 Traditional Farmer Situation .......................... 105
5.2.1.1 Storage for Home Consumption: Base Run ........ 105

5.2.1.2 Storage for Home Consumption: Sensitivity
Analysis .................................... 106
5.2.2 Advanced Farmer Situation ........................... 111
5.2.2.1 Storage for Home Consumption: Base Run ........ 111

5.2.2.2 Storage for Home Consumption: Sensitivity
Analysis .................................... 113
5.2.2.3 Storage for Home Consumption: Summary ......... 129
5.2.2.4 Storage for Future Sale: Base Run ............... 131
5.2.2.5 Storage for Future Sale: Sensitivity Analysis ........ 135
5.2.2.6 Storage for Future Sale: Summary ............... 146

5.3 The Store vs. Selling Decision ................................. 153

vii

CHAPTER 6 SUMMARY AND CONCLUSIONS ......................... 160
6.1 Thesis Summary ........................................... 160
6.2 Empirical Results: Rates of Return to Improved Storage ............ 167
6.3 Limitations, Policy Implications and Research Needs ............... 171

BIBLIOGRAPHY ................................................... 196

Table 2.1
Table 2.2
Table 3.1

Table 3.2
Table 3.3

Table 3.4
Table 3.5

Table 3.6

Table 3.7

Table 3.8

Table 3.9

Table 3.10
Table 3.11

Table 5.1

Table 5.2

Table 5.3

Table 5.4

Table 5.5

Table 5.6

Table 5.7

Table 5.8

LIST OF TABLES

Common Insect Pests of Cowpeas in Africa. ................... 14
Traditional/ Producer Storage Structures Used in Africa. .......... 16
Area Harvested, Total Production, and Estimated Yield for

Cowpea, Far North Province, Cameroon, 1984 to 1989. ........... 30
Major Production-System Zones, Far North Province, Cameroon. . . . 32
Extension Recommendations for COWpeas Northern Cameroon,

1984 to 1991. ........................................... 37
Results of Solar Heater Treatments on Emergence of Cowpea

Weevil by Type of Underlayer Materials. ...................... 45
On-Farm Demonstrations of Improved Storage Technologies,

Northern Cameroon, 1990-91. .............................. 48

Locations In Which Interviews Were Conducted and the Numbers
of Villages and Households Within Each Location, Northern

Cameroon, 1990. ........................................ 51
Farm Characteristics and Management Practices of Sampled
Cowpea Farmers, Northern Cameroon, 1990 .................... 53

Characteristics of CowPea Farmer Types, Based on Adoption
Level of Improved Production Practices of Survey Respondents,

northern Cameroon, 1990. ................................. 56
Storage Practices at the Time of Sampling by Farmer

Classification. .......................................... 65
Storage Losses by Influential Field Practices. ................... 68
Storage Losses by Type of Treatment. ........................ 69
Initial Investment Cost of Various Storage Technologies ........... 95
Estimated COWpea Consumption Schedule and Months of Self-

Sufficiency for Two Farmer Categories, Northern Cameroon. ...... 98

Base Run for ”Traditional” Farmers: Partial Budget and Rate of

Returns Analysis of Improved COWpea Storage Technologies for

Grain Intended for Home Consumption. ...................... 107
Sensitivity Analysis: ”Traditional" Farmer Using Improved Ash

Storage Technology, Values of Key Parameters and Subsequent

Changes in the ARR and MRR, northern Cameroon. ............ 108
Sensitivity Analysis: "Traditional” Farmer Using Triple Bag

Storage Technology, Values of Key Parameters and Subsequent

Changes in the ARR and MRR, northern Cameroon. ............ 109
Sensitivity Analysis: "Traditional" Farmer Using Solar Heater with

Triple Bagging Storage Technology, Values of Key Parameters and
Subsequent Changes in the ARR and MRR, northern Cameroon. . . . 110
Base Run for ”Advanced" Farmers: Partial Budget and Rate of

Returns Analysis of Improved Cowpea Storage Technologies for

Grain Intended for Home Consumption. ...................... 114
Sensitivity Analysis: ”Advanced” Farmer Using Improved Ash

Storage Technology, Values of Key Parameters and Subsequent

Changes in the ARR and MRR, northern Cameroon. ............ 115

viii

Table 5.9

Table 5.10

Table 5.11

Table 5.12

Table 5.13

Table 5.14

Table 5.15
Table 5.16

Table A1

Table A2

Table A3

Table A4

Table A5

Table A6

Table A7

Table A8

ix

Sensitivity Analysis: "Advanced” Farmer Using Triple Bag Storage
Technology, Values of Key Parameters and Subsequent Changes in

the ARR and MRR, northern Cameroon. ..................... 116
Sensitivity Analysis: ”Advanced" Farmer Using Solar Heater with

Triple Bagging Storage Technology, Values of Key Parameters and
Subsequent Changes in the ARR and MRR, northern Cameroon. . . . 117
Partial Budget and Rate of Returns Analysis of Improved COWpea
Storage Technologies for Grain Intended for Future Sale: Base

Run for Advanced Farmers. ................................ 134
Sensitivity Analysis: "Advanced" Farmer Using Improved Ash

Storage Technology, Values of Key Parameters and Subsequent

Changes in the ARR and MRR, northern Cameroon. ............ 150
Sensitivity Analysis: “Advanced“ Farmer Using Triple Bag Storage
Technology, Values of Key Parameters and Subsequent Changes in

the ARR and MRR, northern Cameroon. ..................... 151
Sensitivity Analysis: "Advanced" Farmer Using Solar Heater with

Triple Bagging Storage Technology, Values of Key Parameters and
Subsequent Changes in the ARR and MRR, northern Cameroon. . . . 152
Net Present Value (3% Discount Rate) of the Net Returns to

Stored Grain in the Respective Month Sold. ................... 158
Net Present Value (1.5% Discount Rate) of the Net Returns to
Stored Grain in the Respective Month Sold. ................... 159

Sensitivity Analysis: 'I‘raditional" Farmer Using Improved CowPea
Storage Technologies for Grain Intended for Home Consumption;

Run 1, Household Losses + /- 50%. .......................... 178
Sensitivity Analysis: "Traditional" Farmer Using Improved Cowpea
Storage Technologies for Grain Intended for Home Consumption;

Run 2, Improved Technology Losses + /- 50%. ................. 179
Sensitivity Analysis: "Traditional" Farmer Using Improved Cowpea
Storage Technologies for Grain Intended for Home Consumption;

Run 3, Input Cost + /- 25% ................................. 180
Sensitivity Analysis: "Traditional" Farmer Using Improved COWpea
Storage Technologies for Grain Intended for Home Consumption;

Run 4, Market Price of Cowpea Grain + /- 25%. ................ 181
Sensitivity Analysis: ”Traditional" Farmer Using Improved Cowpea
Storage Technologies for Grain Intended for Home Consumption;

Run 5, Opportunity Cost of Capital/Interest Rate + /- 50%. ....... 182
Sensitivity Analysis: ”Advanced” Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Home Consumption;

Run 1, Household Losses + /- 50%. .......................... 183
Sensitivity Analysis: ”Advanced" Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Home Consumption;

Run 2, Improved Technology Losses + /- 50%. ................. 184
Sensitivity Analysis: ”Advanced” Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Home Consumption;

Run 3, Input Cost + /- 25% ................................. 185

Table A9

Table A10

Table All

Table A12

Table A13

Table A14

Table A15

Table A16

Table A17

Table A18

X

Sensitivity Analysis: “Advanced“ Farmer Using Improved COWpea

Storage Technologies for Grain Intended for Home Consumption;

Run 4 Market Price of Cowpea Grain +/- 25%. ................ 186
Sensitivity Analysis: “Advanced“ Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Home Consumption;

Run 5 Opportunity Cost of Capital/Interest Rate + /- 50%. ....... 187
Sensitivity Analysis: ”Advanced“ Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Home Consumption;

Run 6, Solar Heater with Triple Bag Technology 100% Protection. . . 188
Sensitivity Analysis: ”Advanced" Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Future Sale; Run 1,
Household Losses 4» /- 50% ................................. 189
Sensitivity Analysis: “Advanced" Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Future Sale; Run 2,
Improved Technology Losses + /- 50%. ....................... 190
Sensitivity Analysis: ”Advanced" Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Future Sale; Run 3,

Input Cost +/— 25%. ..................................... 191
Sensitivity Analysis: ”Advanced" Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Future Sale; Run 4

Market Price of Cowpea Grain + /- 25%. ..................... 192
Sensitivity Analysis: "Advanced" Farmer Using Improved Cowpea

Storage Technologies for Grain Intended for Future Sale; Run 5
Opportunity Cost of Capital/Interest Rate + /- 50%. ............. 193
Sensitivity Analysis: ”Advanced” Farmer Using Improved COWpea

Storage Technologies for Grain Intended for Future Sale; Run 6,

Solar Heater with Triple Bag Technology 100% Protection. ........ 194
Sensitivity Analysis: ”Advanced” Farmer Using Improved COWpea

Storage Technologies for Grain Intended for Future Sale; Run 7,

20% Premium Paid for Improved Quality Grain. ................ 195

Figure 3.1

Figure 3.2
Figure 3.3
Figure 3.4
Figure 4.1
Figure 5.1

Figure 5.2
Figure 5.3

Fighre 5.4

LIST OF FIGURES

Map of the Major Production-System Zones of the Far North Province,

Cameroon .............................................. 3 1
Map of Surveyed Districts (March 1990), Far North Province, Cameroor89
Traditional Grain Storage Technologies ........................ 60
The Cowpea Grain Storage Process, Northern Cameroon .......... 62
Effects of Declining Grain Stocks on Market Price ............... 75
Insect Population Growth, On-Farm Trials and Farmers’ Samples,

Cameroon ............................................. 101

Seasonal Cowpea Prices, Far North Province, Cameroon, 1989-1990 . 102
Net Present Value (3% Per Month Discount Rate) of Grain Sold in

Respective Month ....................................... 156
Net Present Value (1.5% Per Month Discount Rate) of Grain Sold in
Respective Month ....................................... 157

ARR

CFA

CIMMYT

CRSP

IRA

IRR

MESIRES

MINAGRI

MRR

NCRE

NPV

ROR

SAF GRAD

SOCECOTON

TLU

USAID

KEY TO ACRONYMS

Average Rate of Return

African Financial Community franc

International Maize and Wheat Improvement Center
Collaborative Research Support Project
International Institute of Tropical Agriculture

I ’Institut de Recherches Agronomiques

Internal Rate of Return

Ministere de I’Enseignement Superieur, de l 'Informatique et de la
Recherche Scientifique

Ministry of Agriculture, Government of Cameroon
Marginal Rate of Return

National Cereals Research and Extension Training Project
Net Present Value

Rate of Return

Semi-Arid Food Grain Research and Development project
Societe dc Developpement du Coton

Testing-Liaison Unit

United States Agency for International Development

CHAPTER 1 INTRODUCTION

1.1 Problem Statement

COWpeas are an important grain legume which is widely grown throughout Sub-
Saharan Africa and northern Cameroon. Because many low income households rely on
cowpeas as their primary source of vegetable protein, crop improvement research
initially focused on increasing crop yields, primarily through introducing new high-
yielding varieties. In the mid-19808, on-farm research showed that grain losses due to
storage pests, particularly bruchids (Callosobruchus maculatus), were a major farm level
constraint (Singh and Rachie, 1985).

To address this constraint, in 1986 scientists at Purdue University and the
Cameroonian Institut de la Recherche Agronomique (IRA), under the auspices of the
Bean/COWpea Collaborative Research Support Program (CRSP), initiated research to
develop bruchid-resistant varieties and improved post-harvest storage technologies.

During the late-1980s, several alternative cowpea storage technologies were
tested, including multiple bagging (plastic) techniques, storage with botanicals (i.e., roots,
mint leaves, bark, neem and shea oil, and ash), and various types of containers. In
addition, CRSP scientists conducted laboratory and field experiments at Purdue and
Maroua, Cameroon to evaluate the feasibility of using solar radiation to kill COWpea
bruchids. Initial experiments showed that brief exposure to temperatures of 65 degrees
C for 5 minutes will kill 100% of all stages of C. maculatus. These results led to the
design of a solar heater (made of two plastic sheets and a insulting ”mattress" of
threshed COWpea pods between the lower black heat-absorbing sheet and the earth),

which was tested in research station and on-farm experiments in Maroua, Cameroon.

2

Results from these trials demonstrated that the solar heater technology effectively
eliminated C. maculatus infestations, and represented a potentially promising, low-cost
technology for extension to farmers.

This thesis analyzes the benefits and costs of the proposed COWpea storage
technologies (i.e., improved ash, triple bagging, solar heater with triple bagging) under

the socioeconomic situation facing northern Cameroonian farmers.

1.2 Objectives

The general objective of this case study is to assess the feasibility and profitability
of proposed storage technologies for COWpeas in northern Cameroon, and to explain the
factors that may condition their rate of adoption.

The specific objectives of the study are to:

a. Document the status of cowpeas in Africa including their place in the

cropping system and their importance in the diet;

b. Document the levels of storage loss caused by the major COWpea storage
insect pests;
c. Describe the traditional and improved storage structures and treatments

that farmers and scientists have developed to reduce storage losses;

d. Document the status of COWpeas in northern Cameroon,- including how
they are grown, utilized, and stored;

e. Review Purdue University/IRA research designed to reduce pest damage,

including breeding initiatives and storage technologies;

3

f. Develop a benefit-cost model, based on farm budgets to estimate financial
returns (net benefits) to farmer-adoption of the proposed storage
technologies;

g. Conduct sensitivity analysis on the variables included in the benefit-costs
model to determine the relative impact of key variables on farmers’ net
benefits;

h. Provide CRSP researchers with guidelines as to socioeconomic data needs

to help plan and evaluate future crop storage projects.

1.3 Hypotheses

This study tests the hypothesis that improved on-farm, low resource storage
technologies have high financial and economic returns when measured against the
farmers’ alternative storage technology. Specifically, it will determine if the net benefit
to investment in each of the proposed improved storage technologies are greater than
zero. Furthermore, it tests the hypothesis that net benefits are highly sensitive to the
cost of materials used to build the improved technologies, (e.g., plastic solar heater and
plastic bags), the market price of COWpeas, the volume of grain farmers have to store, the

level of loss incurred during the storage period, and the opportunity cost of capital.

1.4 Thesis Organization

The thesis is divided into six chapters. Chapter 2 provides general background
about cowpeas in Africa, major storage insect pests, and traditional and improved
storage methods. Chapter 3 reviews the status of cowpeas in northern Cameroon,

including estimates of storage losses under alternative storage structures and treatments,

4

and describes Purdue University/IRA breeding initiatives and storage technologies
developed for low resource farmers. Chapter 4 presents the research design and
methodology. Chapter 5 reports estimates of the benefits and costs of the alternative
technologies and factors found most critical to determining net benefits. Chapter 6
summarizes the thesis, draws policy implications, discusses the limitations of the study,

and identifies future research issues.

CHAPTER 2 COWPEAS IN AFRICA

2.1 Overview of COWpeas

Africa accounts for an estimated 78% of the world’s 8.5 million hectares of
harvested area in COWpeas. Of the 6.7 million hectares in Africa, about 61% are in
Nigeria, followed by Niger (23%), Burkina Faso (4.6%), Mali (2.5%), Ghana (2.3),
Tanzania (1.4%), and Senegal (1.4%) (Bernsten, 1993).

In these countries, COWpeas are grown primarily in the semi-arid regions, where
annual rainfall averages 400-1000 mm. In much of the cowpea-growing area, the rainfall
coefficients of variations range from 20-40 percent. Because of this extreme variability in
year-to-year rainfall, farmers face considerable production risk (Bernsten, 1993).

To assess the relative importance of cowpeas in the food system, Bernsten (1993)
calculated the area (harvested) in COWpeas vs. total cereals, roots and tubers, and pulses.
Although in most countries cowpeas represent a relatively large share of the pulse area,
they represent only a relatively small share of the total harvested crop area.

2.1.1 Cropping System

COWpeas, the second most important grain legume in Sub-Saharan Africa after
groundnuts, are predominantly cultivated in the semi-arid regions of the continent.
Yields for local varieties are generally low, ranging from 200 to 350 kg/ ha. COWpeas are
a particularly appropriate crop for limited-resource farmers because they have the ability
to fix nitrogen, which improves soil fertility, and reduces the need for farmers to
purchase costly nitrogenous fertilizers. In addition, cowpeas are drought-tolerant, which

reduces farmers’ exposure to risk.

6
About 85% of Africa’s cowpea area is intercropped with other grains (e.g.,

sorghum, millet, or maize). Traditionally, farmers prefer intercropping spreading-type
varieties because it helps to reduce weed populations by shading out light, thereby
limiting weed growth. Intercropping also reduces insect pest populations by: 1)
restricting the movement (barrier effect) of thrips, leafhoppers, and aphids; 2) through
the effect of canopy shading, which increases the humidity and reduces the temperature;
and 3) supporting natural predator populations which reduce cowpea pest populations.

Research to increase COWpea yields has focused on developing erect varieties
appropriate for monoculture cultivation (IITA, 1992). While the recent development of
higher yielding improved COWpea varieties have increased the crop’s yield potential,
adopting these varieties requires farmers to radically modify their traditional cropping
practices. Not only must farmers monocrop these improved varieties, but they must also
apply insecticide to control insect populations. If these recommendations are not
followed, farmers seldom achieve the anticipated benefits of the improved varieties
(IITA, 1992).
2.1.2 Utilization of CowPeas

COWpeas are used throughout semi-arid Sub-Saharan Africa as a food source for
both humans and animals. COWpea grain, available in a wide assortment of colors (e.g.,
red, yellow black, brown, purple, and white), is commonly used as an ingredient in soups,
stews, sauces, and casseroles. Additionally, West Africans use COWpeas to prepare a
paste which is used in fried and steamed dishes (Bergman, 1990). Green COWpea leaves
are widely consumed as a fresh vegetable; and in the drier regions of West Africa, leaves
are harvested, dried, and stored for later use. In some areas, COWpeas are ground into a

flour and incorporated into biscuits, cookies, doughnuts, and pasta (Bergman, 1990).

7

Cowpea protein is rich in amino acids which are deficient in grains-making it an
important complement to the grain-based diet of the poor. In addition, cowpeas are an
important weaning food. Children, unable to consume sufficient bulk to meet their
protein needs from grains, can meet these requirements from consuming more highly
concentrated COWpea protein1 (Ferguson and Horn, 1984). Compared to meat, cOWpeas
are a relatively inexpensive source of protein On a unit weight basis, it also yields
almost as many calories as cereals. Finally, cowpeas are a fairly good source of
thiamine, niacin, calcium and iron.

In low rainfall regions, cowpea fodder is fed to cattle, both as freshly harvested
green fodder and as dry fodder during the off season (Singh and Rachie, 1985). In
addition, insect and fungus damaged cowpea seeds are typically fed to chickens and other

farm animals.

2.2 Storage of Grains

Households store grain for three purposes: to retain for home consumption, to
trade in the market, and to retain seed for planting the following year (Hall, 1970).
Storage is carried out by the producer, the trader, the processor, and the exporter, which
may be the same person(s) on a low resource African farm.

In most low-resource farming communities, households depend primarily on own—
production for their daily food supply. Since the harvested crop must be stored for up to
a year until the next harvest, safe storage is required to insure food security. According

to McFarlane (1988), 70% or more of the cereal grain produced in Africa is stored at

 

1The crude protein content of cowpea range from 23 to 30%, crude fat from 1.6 to
2.1%, and carbohydrate from 56 to 68% (Bergman, 1990). In contrast, the crude protein
content of maize is 9%.

8
the farm level, for 6-12 months. Producers who sell part or all of their crop at harvest
usually receive a relatively low price for their crop because of the abundant supply on the
market. Thus, reducing storage losses has the potential to enable producers to store and
then sell their commodity at higher prices when the market supply is lower.

At the village level, low-resource producers generally utilize traditional grain
storage methods, which vary by region and commodity. The specific storage method
used depends on such local factors as: (a) type of produce, (b) duration of storage, (c)
value of produce, (d) climate, (e) cost and availability of labor, (f) cost and availability of
materials and resources, (g) incidence of insect and rodent pest infestation, and (h)
transportation system.

Regardless of the storage method, to minimize losses farmers must place dry,
clean, uninfested grain in a sound, clean, uninfested storage container.

2.2.1 Damage vs Loss of Foodstuffs

It is important to distinguish between ”damage" and "losses" to foodstuffs because
each term has a different connotation and measurability. Yaciuk and Forrest (1979)
define "damage" as:

”some stage of deterioration of a foodstuff which may or may not be acceptable

to the consumer. This acceptance depends on the consumer’s economic level and

cultural background. Certain societies discern between what can be eaten but not

sold, as well as what can be eaten by some and not by others. Additionally,

acceptance of a foodstuff depends on the quantities of food on hand; generally,

the consumer accepts a more damaged foodstuff if his food supply is limited.”
Given Yaciuk and Forrest’s definition, it is difficult to measure ”damage" objectively.
Therefore, the following analysis focuses on analyzing "losses”.

”Loss" denotes the disappearance of a foodstuff. Yaciuk and Forrest (1979)

define the following types of foodstuff losses:

1)

2)

3)

4)

5)

9

Loss of weight, which can be defined and measured accurately and
economically;

Loss in quality, which depends on locally accepted standards and is
difficult to assess unless acceptance/rejection criteria are used;

Nutritional loss, which can be defined and measured accurately;

Germinative loss, which is diffith to evaluate and is only important when
grain is stored for seed or when used in processing such as brewing;

Loss in goodwill, which is very diffith to measure accurately. If grain is
sold, the buyer expects a certain standard of product from the seller. If
this expected standard is not met, the buyer may seek markets elsewhere,
resulting in a loss to the seller.

Yaciuk and Forrest (1979) warn that loss, particularly economic loss, must be

examined in view of the total situation, rather than as a separate entity. For example, in

some West African countries, the price of COWpeas just before planting may be five times

the harvest price. Thus, if a farmer incurs a physical loss of 50% by storing his/her crop

until the price increases, he/she may not suffer an economic loss of 50%, but rather an

economic gain of 250%.

To a farmer, loss of a foodstuff may not have the same meaning as to a scientist.

While it is difficult to accurately measure the farmer’s concept of loss, knowing what

farmers do (and why) and the reasons farmers accept losses will help scientists to design

improved storage technologies and practices. Adams (forthcoming) observed that

farmers may accept losses for several reasons, including:

1)
2)
3)

4)

ignorance of the loss;

awareness of the loss, but acceptance of it as inevitable;

concern, but unawareness of what can be done to reduce the loss; or
concern, but acceptance of the loss, despite the availability of control

measures.

10

Furthermore, even damaged grain has an economic value. For example, in West
Africa, cowpeas damaged too badly for human consumption are fed to animals, which in
turn are either consumed or sold by the farmer.

Therefore, efforts to improve farmers’ storage methods must take into account
the farmer’s practices and attitudes toward foodstuff losses. For the purposes of this
paper, the term ”losses" will apply to changes which can be quantified (i.e. number of
emergence holes per cOWpea grain) by scientific means.

2.2.2 Where Losses Are Incurred

Although losses are incurred at all stages in the post-production system, including
during field drying, harvesting, threshing, shelling, drying, storage, processing, and
consumption, storage losses are the primary concern of this paper. The main causes of
storage losses are insects, vertebrate pests (i.e. birds and rodents), molds, and fungi.
According to Schulten (1988), the losses at each individual stage of the post-harvest
system may be relatively small and uneconomic to reduce, but when combined they result
in post-harvest losses of 10-20 percent.

Most of the literature focus on losses incurred by households storing their own-
production. Yet, greater losses are possibly experienced in trader-managed commercial
storage systems where grain is typically stored unprotected in bags.

2.2.3 Farm Level Storage Losses

Much of the research on improving small-farm grain storage employ surveys and
trials to assess the magnitude of current losses. These data show that losses are highly
variable, depend on the assessment method used, the quality of the work, and the season
and regions sampled (Rukuni, 1987). Although losses vary by location and are crop

specific, Schulten (1988) provides some general estimates of farm level storage losses.

 

 

 

11

According to Schulten, farm level losses, expressed as weight loss of the initial quantity
stored, are in the order of 1.5% for insect losses, 05-25% for mold and 0.5-1% for
rodent losses when grain is stored for up to 9 months. He also asserts that often farmers
consider these losses too low to take effective action. Similarly, based on a review of the
literature, Giga, Mutemerewa, Moyo, and Neeley (1991) report that farm level storage
losses are generally low. For example, De Lima (1979) estimated a 6% annual weight
loss due to insects and rodents in Kenya, whereas Golob (1981) reported losses of 2% in
sorghum and 3% in maize in Malawi.

In contrast, Singh, Luse, Leuschner, and Nangju (1978) observed that severe
losses due to the COWpea weevil have been reported in several tropical and subtropical
countries. For example, Caswell (1968) found that COWpeaS stored for 9 months in
traditional storage containers in northern Nigeria suffered 32% and 87% damage
(expressed as weight loss) when stored as unshelled and shelled COWpeas, respectively.
These accounts suggest that it is difficult to generalize regarding storage losses. The
magnitude of storage losses varies from region-to-region and accurate estimates for a
particular case requires location and system specific analysis.

Unfortunately, most case studies reporting food stuff losses fail to describe the
storage method (i.e., the storage structure or treatment the food received) under which
the losses occurred. McFarlane (1988) reports a range of 4-5% for on-farm losses to
stored cereal grains in Africa and states that losses in excess of the indicated range occur
sporadically in both on-farm and off-farm storage. Severe losses are generally caused
either by shortcomings in management or by unexpected, adverse conditions. In general,
variations in farm-level storage losses are more closely related to climate than to the

chosen storage technique (McFarlane, 1988). There are, however, clear differences in

 

 

 

12

the nature and extent of storage losses associated with the various storage techniques.
For example, storing shelled maize in woven sacks will lead to accelerated damage by
grain weevils, grain beetles and warehouse moths. In contrast, storing sound, dry cobs in
traditional cribs generally retards damage by these insects, while permitting greater
damage by the grain moth.

The observed correlation between the magnitude of losses and storage time
indicates that losses rise disproportionate to storage time increases. Yet, Richter (1988)
points out that ”in practice loss figures are fortunately much lower than the percentages
given, because the consumption of grain is almost steady from the harvest on, thus the
amount of grain stored is continually decreasing and high losses are only sustained
towards the end of the storage period on a small quantity of grain."

Furthermore, Giga, Mutemerewa, Mayo, and Neeley (1991) observed that when
the traditional system is disturbed by the introduction of new technologies, such as high
yielding varieties (hybrids) or new pest problems, losses may increase significantly.
Problems associated with newly-developed varieties include varieties that: mature before
the end of the rainy season, making it more difficult to dry the harvested grain; have
lower resistance to insects and molds; and have softer pods or kernels which are more
prone to insect attack. Schulten (1975) observed large differences between maize
varieties in terms of their susceptibility to storage pests in Malawi. He found that hybrid
varieties were the most susceptible, reporting storage losses of 10% for hybrid SR 52. In
contrast, widely cultivated traditional maize varieties suffered storage losses of only 1-3%

and improved open-pollinated varieties incurred losses of 5%.

 

 

13
2.3 Insect Pests of Cowpeas

Cowpea, Vigna unguiculata (L.) [Walpers], like other grain legumes, are infested
by both field and storage pests. Important pests found throughout its geographical
range, include aphids, beanfly, leafhoppers, thrips, pod borers, pod-sucking bugs, cowpea
curculio and the storage beetle (Table 2.1).

Bruchidius atmlineatus, a field pest, damages dry seeds in the pods, does not
continue to damage stored seeds. Callosobruchus maculatus, commonly known as the
cowpea weevil, is another major storage pest (Singh and Rachie, 1985; Kitch, et al.,
1991). COWpea weevil infestations begin at low levels in the field as the pods near
maturity. But because of the rapid natural increase while in storage, the stored grain can
be destroyed within a few months, long before the nest year’s harvest (Murdock and
Shade,1991)

Adult female C. maculatus can lay 50-80 eggs on each pod. After the larvae
hatch in about 3-5 days, they bore into the seeds, where the larval and papal stages are
found. The adult emerges after about 20 days (Singh and Rachie, 1985) completing the
life cycle in about 30 days. Grain damage results from larvae feeding inside the seed.
After six months, Singh and Rachie (1985) report farm storage grain losses of 30% in
terms of weight and up to 70% in terms of seeds infested, making the grain virtually

unfit for consumption.

14

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 2.1 Common insect pests of cowpeas in Africa.
Pest Status Common Name Scientific Name Damage
Major Pests Cowpea aphid Aphis craccivora Feeds on foliage, pods, at
seedling stage
Legume bud thrips Megalunothrips sjostedti (syn. Taeniothrips Damages flower buds,
sjostedti) flowers
Legume pod borer Mar-uca Testulalis Feeds on flower buds,
flowers, green pods
Coreid bugs Anoplecnemis curvipes, Riptortus dentipes, Feeds on green pods
Cavigralla tomentosicollis (syn. Acanthomis
tomentosicollis), C. shadabi (syn. A.
horrida), C. elongata
Cowpea storage Callosobrucbus maculatus, C. chinensis Damage seeds in storage
weevil
Minor Pests Striped foliage Medythia quaterna (syn. Luperodes lineata) Feeds on foliage at seedling
beetles stage
Pea aphid Aphis fabae Feeds on foliage at seedling
stage
Other beetles Lagria villosa, Chrysolagria spp. Foliage feeders
Leaflioppers Empoasca signata, E. dolichi Feeds on foliage at seedling
stage
Pod weevil Pinotrachelus varius (syn. Apion varius) Feeds on seeds within green
pods
Beanfly Melanagromyza phaseoli Feeds on stem at seedling
stage
Pod borer Cydia ptychora (syn. uspeyresia ptychora) Feeds inside green pods
Green stink bugs Nezara viridula, Aspavia armigera Feeds on green pods
Foliage thrips Sericothrips occipitalis Feeds on foliage at seedling
stage
Lima bean pod borer Etiella zinckenella Feeds on green pods
Foliage beetles Ootheca mutabilis, O. bennipeni Feeds on foliage at seedling
stage
Sporadic Pests Striped bean weevil Alcidodes leucogrammus Feeds inside stem and on
foliage
African bollworrn Heliothis amigera Feeds on green pods,
flowers, foliage
Blister beetles Mylabris farquharsoni, M. amplectens, Flower feeders
Coryna apicicornis
Egyptian leaf worm Spodoptera littoralis (syn. Prodenia litura) Feeds on green pods,
flowers, foliage

 

 

 

Source: Singh and Rachie (1985).

 

15

2.4 Traditional Grain Storage Structures

In the tropics and subtropies, food grains are mostly stored using traditional
methods, which vary in their ability to insure safe storage. Performance variations are
often influenced by climate, local availability of suitable materials, labor availability,
investment capital, and local customs (McFarlane, 1988). The range of storage structures
encountered in these regions is presented in Table 2.2.

Local experience and traditions have contributed to the development of many
storage techniques. According to Richter (1988), factors which contribute to successful
storage include:

(1) harvesting of grain during a pronounced dry season, which facilitates drying of
the harvested grain;

(2) predominance of hard grain, which discourages insect pests;

(3) unthreshed storage, which further discourages insect pests;

(4) the use of traditionally-proven repellents such as ashes, weeds, and dusts; and

(5) storage structures which allow complementary drying, but prevent
rehumidification in the next rainy season, such as good mud or pottery granaries

and pits. Also, well-constructed storage structures protect the grain against flood
water, rodents, and birds.

16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 2.2 Traditional/Producer Storage Structures Used in Africa.
Storage Method Spud-l Mas-es Product
UNCOVERED
No structure Heaped on ground Paddy, groundnut
Vertical pole Tied to poles Maize
Horizontal cords or creepers Hung on these strands which are tied between poles or Maize

trees
Vertical racks Hung on horizontal poles fixed to vertical poles Paddy
Platform Heaped on platform Maize, pulses,
groundnut
Open baskets Raised 1 meter or more above ground Paddy, maize,
A groundnut
Sacks Placed on platform 1 meter high Paddy
COVERED
Horizontal grid Hung on horizontal poles; covered with loose thatch Paddy
roof
Platform Heaped on platform; covered with ’straw hat’ which Paddy, maize
rests on platform
Granary
(a) Simple type (usually Constructed of plant material raised above ground, All types
cylindrical) with thatch roof
(b) Structure incorporating As (a) but with mud of clay worked into floor and All types

clay

walls

 

(c) Wall of clay mixed with
plant material supported by

timber frame

Cylindrical or elliptical, raised above ground

Cereals, paddy, millet,
sorghum

 

(d) As (c) but not

supported by timber frames

Jar-shaped, raised on 'foot' of clay or log. Sometimes
divided into compartments.

Maize, sorghum, millet

 

(e) Wall of clay only

Various shapes, “straw hat'

Cereals, groundnut

 

Clay jar (usually kept in living

Sealed with damp earth; sealed with flat stone and

Maize seed, all types of

 

 

 

 

 

 

 

 

 

netting

hut) clay; partially baked before storage; produce mixed grain, maize meal,
with uh, jar sealed with clay; produce mixed with ash. maize. sorghum
Gourds Sealed with clay; plugged with stems of plant All types, maize, grain
Baskets Usually placed in kitchen Groundnut, paddy
(seed), beans
Commodity wrapped in matting Kept in living hut All types
Stored under roof of living but Small bundles hung from roof above fire Cereals
Stored on floor of living but Temporary storage Paddy
Underground storage Sometimes lined with cow dung and fired. Opening Cereals
sealed with clay of grass thatch and thorns
Communal store Large crib of millet stalks of bamboo (12-ton capacity) Paddy
'Improved traditional' cribs Square sided crib with timber frame and walls of wire Maize

 

Source: D.W. Hall (1970).

 

17

Typically food grains are first gathered on the ground to facilitate their removal
from the field. Usually these heaps are only left for a few hours, or a day or two at the
most. But, if the harvesting of the one crop coincides with another, the grain may be left
on the ground for quite some time. Since this is a deliberate act on the farmer’s part, it
may be considered a temporary storage method (Hall, 1970).

In many areas, farmers temporarily store grain on platforms (covered or
uncovered) as an intermediate between a granary or other storage vessel. Although
unthreshed grain on uncovered platforms is exposed to the elements and various storage
pests, solar radiation reduces insect pest populations for a period of time. In more
humid regions, some food grains are first dried over an open fire, on a platform covered
by a thatched roof.

Commonly, unhusked maize is hung in bundles between poles or trees. The
maize husk serves as a natural physical barrier to many insects, especially if stored for
only a short period of time.

Circular or rectangular granaries-made of plant materials, clay, or mud--are the
most frequently used permanent storage structure. These are usually elevated above
ground level, especially in areas where there is a danger of flood or domestic animals.
The dimensions of the granaries are mainly determined by the quantity of grain to be
stored.

In some countries, grain is commonly stored in compartmentalized bins. These
bins are usually square, with walls about 3 meters long and 1.5-2 meters high, and are
divided into four or more compartments (Hall, 1970).

In several regions in India, Africa, and Latin America farmers commonly stored

grain for long periods in airtight underground pits, which are rarely opened (McFarlane,

 

 

18
1988; Hall, 1970; Sibisi, 1984). Richter (1988) reports that gain kept in pits may last 3
to 4 or more years, with minimal losses. Pits are typically sealed with either dung, a
large stone embedded in mud, or a dry earth cap. Sometimes these pits are lined with a
gass matting; while in other areas they are lined with stones or bricks and covered with
clay to give a smooth hard finish. These pits are often located in enclosed areas where
cattle are. kept because these sites are generally free from termites and are relatively dry
(Hall, 1970). While pests trapped in such a repository are asphyxiated and die quickly
(Sibisi, 1984), if the moisture content is over 12-13%, gain should not be stored in an
airtight container because it will mold (Lindblad and Druben, 1976).

The storage methods so far described are most appropriate for relatively large
quantities of unthreshed gain. If the crop is small or gain is to be removed from the
ganary for food preparation, it is usually stored threshed or unthreshed in smaller
containers such as small baskets or jars, which can be easily carried.

Baskets, in an infinite variety of sizes and desigrs, are generally used to
temporarily store gain that will be used soon. When baskets are used for long term
storage, they are kept in the dwelling hut or on top of other produce in a larger
container or ganary, usually covered with some type of matting or leaves (Hall, 1970).
In many areas, households store gain in woven bags with an open mouth, made from
local fibers. These containers usually have fiber or leather straps for carrying.

Farmers often store gain in calabashes, gourds or earthenware jars, sealing the
mouth with clay, mud, dung, or a wooden stopper. In some countries the gain is first
mixed with ash, then stored in large pottery vessels, and covered with clay/ ash or stacked
one on top of each other. Finally, food gains are commonly stored in the dwelling but

on lofts that are either built over the fireplace or across the whole round hut.

 

 

19

2.5 Traditional Grain Storage Treatments

Prior to storing the gain, farmers employ a variety of cultural, physical, and
biological techniques to reduce gain losses.
2.5.1 Various Ashes and Inert Dusts

Traditionally, farmers have stored gains mixed with inert dusts made from clays,
diatomite, wood ash, cow dung ash, silicates and sand to slow insect population gowth.
De Lima (1987) reports that mortalities result from both abrasion of the insect cuticle
(resulting in dehydration) and through physical impediment when at least 20% of the
produce by volume is mixed with the inert material. In addition, ashes, powder and sand
reduce insect pest damage by filling interstitial spaces and/ or creating a barrier to insect
movement. In Ghana, mahogany ash is used to protect millet against stored products
insects (Minor and Williams, 1930) and Cobbinah and Appiah-Kwarteng (1988) report
that neem wood and leaf ashes reduced insect damage to stored maize. Golob and
Webley (1980) observed that the effectiveness of the ash probably varies considerably,
depending on the silica content of the dust and its absorptive and abrasive properties.
2.5.2 Use of Plant Materials

Throughout the developing world, farmers use a number of edible oils (e.g.,
goundnut, palm, copra, citrus, and coconut) and many neem derivatives (i.e., oil, ash,
leaves) to protect against bruchid pests of beans, COWpeas, and pigeon peas (Mital, 1971;
Schoonhoven, 1978; Singh et al., 1978). For example, in Ghana, neem oil is used as a
repellent against storage pests (Tanzubil, 1991). In India, women mix split pigeon peas
and other gain legumes with edible oils before storage.

Scientists have carried out numerous studies to identify the mechanisms by which

these products control storage pests. Singh found that goundnut oil impedes C.

 

 

 

20

P

maculatus progeny emergence on com rather than affecting oviposition or adult
mortality (Singh et al., 1978). Don-Pedro (1988) reports that oils have a lethal effect on
Callosobruchus maculatus eggs (1) by slowly reducing respiratory activity and eliminating
toxic metabolites, as a result of the oil ’barrier effect’; and (2) by penetrating the eggs,
which has a toxic effect. Singh et al. (1978) studied the use of edible oils and their
ability to protect cowpeas from C. maculatus and reported that their mode of action is
partially attributed to interference with normal respiration of the bruchids, resulting in
suffocation. Su et al. (1972) applied oils from the peel of 8 citrus fruits to the surface of
COWpea seed, and adult C. maculatus exposed on the treated cowpeas failed to produce
progeny. Taylor and Vickery (1974) identified the principal component of citrus oil as
limonene, which was found to be a highly effective insecticide. Studies by Bean/COWpea
CRSP scientists showed that storing cowpeas in a mixture of 3 parts wood ash and 4
parts COWpea provided effective protection against C. maculatus. The ash not only slows
down adult emergence from the COWpea seed, but adults who successfully emerge have
difficulty escaping from the ash and eventually die of exhaustion.

Studies have shown that some oils are more effective than others and some may
have undesirable side effects. According to Singh, Luse, Leuschner, and Nangju (1978),
goundnut and castor oil appeared to be superior to coconut or palm oil. Mital (1971)
showed that COWpeas remained protected from beetles when treated with oil, but that
such seeds lost their viability.
2.5.3 Heat and Smoke

In many locations, households store gain above a fire. Exposure to the drying
effects of hot air reduces insect populations through the direct effects of heat and smoke.

Under warm humid conditions, raised ganaries are constructed over a slow-burning fire.

 

 

21

As the hot air moves through the gain, it reduces the moisture content and the smoke
acts as a furnigant (Hindmarsh, Tyler, and Webley, 1978).
2.5.4 Natural Barriers and Resistant Varieties

Farmers have often-selected indigenous gain varieties for their superior storage
characteristics, especially those with resistant gain qualities and physical barriers to
insect attack. Examples of natural barriers include the sheathing leaves of maize cobs,
the pods of gain legumes and the husk of rice paddy. Breeding progams have not
always recognized the importance of storage characteristics. For example, in Belize,
improved maize variety Poey T66 gave higher yields, but was rejected by farmers because
it was highly susceptible to weevil damage, since the sheath did not fully cover the cob
(Bernsten, 1976). Recently, scientists have given high priority to breeding for improved
storage characteristics. For example, in Cameroon, the Bean/Cowpea CRSP places high
priority on breeding improved cowpea varieties with resistance to Callosobruchus
maculatus, and non-dehiscent, breakage-resistant pods (CRSP, 1990).
2.5.5 Synthesis and Implications

Scientists disagee as to the efficacy of the wide variety of traditional storage
methods described above. Studies by the Bean/COWpea CRSP confirmed that in
northern Cameroon ash storage of cowpeas is effective in preventing weevil population
gowth, if the proportion of ash to COWpea is at least 3 parts ash to 4 parts (30pr
(Kitch, 1992). Golob (1984) reports that wood ash and abrasive powders, such as
diatomite, provide some protection in on-farm storage, but are generally much less
effective than the synthetic gain protectants. Experiments have shown that edible oils,
such as palm, goundnut, and coconut are particularly effective against C. maculatus,

which lay their eggs outside the gain (Schoonhoven, 1978; Singh et al., 1978), but less

 

 

 

22

effective against S. zeamais, which inserts its eggs inside maize gains. Finally, Cobbinah
and Appiah-Kwarteng (1988) report that neem oil reduces damage by S. zeamais more
effectively than edible oils.

These studies suggest that before launching a major effort to reduce post-harvest
pest losses, scientists must first assess the magnitude of losses farmers incur using
traditional technology. This will require collecting farmer-stored samples of gain
throughout the storage period and over a representative sample of sites and storage
techniques.

Reducing post-harvest insect losses may require farmers to adopt a variety of
pest and commodity management techniques. Where the storage period spans a wet
season and a dry season, some adjustments in storage management may be needed and,
at the farm level, storage structures may need seasonal modification (Golob, 1984). But
unless farmers believe that losses are substantial and proposed interventions are cost-

effective, few will adopt these recommendations (Rukuni, 1987).

2.6 Breeding Improved COWpea Varieties

Prior to 1970, the international research community paid little attention to
cowpea improvement in Africa. Recognizing the importance of cowpeas for limited
resource farmers, both IITA and the Bean/COWpea CRSP have focused attention on this
legume.
2.6.1 International Institute of Tropical Agiculture

In an effort to increase cowpea production, the International Institute of Tropical
Agiculture (IITA) in Ibadan, Nigeria established a cowpea-improvement progam in

1970. Initially, IITA focused primarily on germplasm collection, evaluation and

 

23

maintenance, and breeding for disease resistance. Since 1980, institute scientists have
placed geater emphasis on breeding for insect resistance, early maturity, improved plant
types and desired seed quality. IITA hopes to develop improved cowpea cultivars, well
adapted to various gowing conditions and make these available to national progams
(IITA, 1992). Efforts to develop insect resistant varieties are particularly appropriate for
limited-resource farmers because they reduce the need to apply costly insecticides and
reduce farmers’ risk to pest damage.

In 1974, IITA initiated an international cowpea disease nursery (ICDN) progam
to identify sources of broad-spectrum, stable resistance to isolates of pathogens from
many different environmental conditions (Singh and Rachie, 1985). This effort identified
several cowpea lines that combined high-yielding potential with multiple disease
resistance, including TVu 201(8), Wu 1190, Wu 1977, and Wu 4557 -- which were the
best performers (Singh and Rachie, 1985). Similarly, sources of resistance to bruchids
have been introduced into several lines including Wu 2027, Wu 11952, and Wu 11953.

In 1975, HTA established a formal cowpea international testing (CIT) progam to
evaluate the several breeding lines being developed through ICDN, and first sent a
standardized trial, consisting of 19 entries, to 55 countries. The CIT has become a key
part of IITA’s cowpea improvement progam and is the main channel for testing and
disseminating improved materials to national research progams.

In addition to multiple disease resistance, the IITA cOWpea-breeding progam
developed very early-maturing varieties that fit into multiple cropping systems. Because
of their short duration, these varieties require fewer insecticide applications than do later
maturing varieties. In addition, the Institute has developed bush-type varieties with

tender pods for use as vegetables (IITA, 1992).

 

24

Although these varieties out-yielded farmers’ varieties, in a recent HTA research
review the Institute acknowledged that adoption of these monoculture varieties made
available in the 1980s was limited, owing primarily to the continual lack of access and
high cost of needed insecticides. As a result of this experience, IITA has refocused their
work with current emphasis on developing COWpea germplasm that is suitable for
intercropping and has high levels of insect resistance.

2.6.2 Bean / Cowpea Collaborative Research Support Progam

The USAID-funded Bean/Cowpea Collaborative Research Support Progam
(CRSP) was established in 1980 to address major worldwide cowpea production and
utilization constraints by forging linkages between Land-Grant university scientists and
cOWpea scientists in developing countries. The Bean/COWpea CRSP currently supports
four research projects on cowpea improvement in three African countries, focusing on
breeding for pest and disease resistance (Cameroon), drought tolerance (Senegal), and

integated pest control and utilization (Ghana).

2.7 Grain Storage Technologies

In addition to breeding for insect resistances, post-harvest scientists have
developed several improved storage methods and structures for (small) on-farm gain
storage. These range from technologies that rely on the use of ”modem” inputs such as
metal drums and silos, concrete silos, plastic bags, mechanical dryers, and insecticides to
improvements in the traditional methods and structures, such as lining pits with various
plant materials, improved sack stacking, and sealing gourds and other containers to make

them airtight.

 

2.7.1 Physical Disturbance

Recently, scientists discovered that the bean weevil could be controlled by
physically disturbing the stored gain. Loschiavo (1978) and Quentin, et al., (1991) found
that mortality of some storage weevils increased when infested sacks of stored gain
where rolled or tumbled. Quentin, et al., (1991) report that brief daily tumbling of beans
held in half-filled jars, buckets, and sacks reduced Acanthoscelides obtectus populations by
97%, relative to stationary controls. Since larvae must wedge themselves between
abutting surfaces in order to successfully bore the gain, repeated tumbling of the beans
prevented them from penetrating the seeds. As a result, the larvae either die of
exhaustion or are smashed by the tumbling beans. Yet, hand tumbling is unlikely to be
as disruptive to the cowpea weevil, Callosobruchus maculatus, since these larvae bore
directly into the gain from eggs glued to the testa (Quentin, et al., 1991).
2.7.1 Hermetic Storage and Silos

Hermetic storage makes it possible to store gain for long periods without
applying fumigants or contact insecticides, especially if bruchids are first killed before
placing the gain into storage. Boxall (1974) reports that semi-hermetic conditions can
be created in traditional undergound gain storage pits and that it was possible to
improve traditional Ethiopian storage methods by linings the undergound pits with
matting and straw, polyethylene sheets, sacks or concrete. Boxall reports these ”linings
reduced damage due to molds by restricting and preventing the ingess of water over a
period of four months and also resulted in less damage due to insects and rodents"
(Boxall, 1974). McFarlane proposed that metal drums, as a form of airtight storage, are
"potentially more completely airtight than any undergound pit” (McFarlane, 1988). In

addition, McFarlane (1970) also examined gourd-storage techniques used in Kenya and

 

26

showed that treating their external surface with linseed oil or varnish, geatly reduced
oxygen permeability. Thus, the container can be used as a semi-airtight receptacle, if
A well sealed at the neck.

Storage of gain in plastic bags has also been tested as a method of airtight
storage for smaller amounts of gain. Yet, because plastic can be punctured or torn
easily, it is generally recommended that the plastic bags be lined with either a cloth sack
or multiple layers of plastic bags (Lindblad and Druben, 1976; Kitch and Ntoukam,
1991a).

Researchers at Purdue University, in association with the Bean / Cowpea CRSP-
IRA Grain Storage Project in Cameroon, devised a solar heater made of two plastic
sheets-~which kills 100% of all stages of C. maculatus, a major cowpea storage pest.
They estimate that the solar heater has a useable life of two years, if properly utilized.

Finally, sheet metal and concrete silos have been recommended for small-farm
gain storage. But because metal silos will rust quickly in hot, wet regions, they must be
galvanized or painted regularly. In many instances, these technologies have been
abandoned because their upkeep was too costly for the farmer (Richter, 1988).

2.7.2 Insecticides

Several insecticides have been used to control storage insect pests in the tropics,
including permethrine, lindane, malathion, pyrethrum, dichlorvos, and phostoxin
(Lindblad and Druben, 1976; nguatu, 1987). These insecticides are of two major types,
contact chemicals and fumigant gases. As the name implies, insects must come in
physical contact with contact insecticides. Contact chemicals are available as dusts,
wettable powders, and liquid concentrates. Highly toxic fumigants penetrate the gain

stored in stacked bags or stored in a silo and kills any infestation present (including eggs

 

27

and other immature stages inside the gains). But fumigants provide only temporary
control, if insects are able to reinfestation the store.
2.7.3 Critique of ’Improved’ Grain Storage Technologies

While potentially successful storage techniques, plastic bags, silos, and insecticides
all have various disadvantages from the farmer’s point of view. In assessing the first
generation of produce storage projects implemented during the 19703 and the early
1980s, Richter (1988) argues that they were poorly prepared and almost all unsuccessful.
These efforts focused too narrowly on constructing farm-size silos built of cement or
cemented mud bricks, and steel drums and bins, which were often expensive to construct
and maintain. Also, these projects promoted the increased use of chemicals in the
storage process. In contrast, according to Richter, storage projects initiated in the early
1980s were more appropriate because they began with in-depth studies of the traditional

techniques and sought to improve upon these existing systems.

2.8 Effects of Storage on Nutritional Properties of Cowpeas

In addition to reducing pest losses, efforts to improve traditional storage methods
need to consider their impact on gain quality. Improper storage may induce textural
defect in legumes, which prolongs cooking time and demands correspondingly higher fuel
inputs (i.e., hard-to-cook defect causes leguminous seeds to remain hard to eat, even
after cooking for an extended time) (Sefa-Dedeh et al., 1979). Research has shown that
if beans and peas are stored at elevated temperatures and high relative humidity, cells
fail to separate following cooking (Jones and Boulter, 1983).

In addition to extending the cooking time and wasting fuel, the hard-to-cook

effect may reduce the nutritional quality of legumes. Studies have found a negative

 

 

28

relationship between long term storage and the protein quality and the availability of
essential amino acids in beans (Molina et al., 1975; Antunes and Sgarbieri, 1979; Sefa-

Dedeh et al., 1979).

2.9 Summary

Cowpeas, one of the most common food gain legumes gown in Africa, are a
staple in the diets of both the urban and rural poor. Average yields are generally low
because farmers face many production constraints and have limited assess to inputs
needed to resolve these problems. Farmers also face storage problems for their COWpea
harvest. In an effort to reduce insect pests in cowpea production and storage, scientists
have employed various approaches. In addition to breeding for insect resistance,
scientists have developed several storage methods and structures for on-farm gain
storage. While potentially effective, many of these technologies are not economically
feasible for the limited-resource farmers to adopt.

Much of the research on improving small-farm gain storage involved surveys and
trials to assess the magiitude of current losses. Based on a review of the literature,
farm-level losses are generally low, crop specific, and vary by assessment method,
location, and season. Numerous traditional gain storage structures and protectants
against insect pest damage are used to minimize on-farm storage losses. These
traditional on-farm storage methods generally provide effective protection for the

relatively small stores of gain low-resource farmers produce.

 

CHAPTER 3 COWPEAS IN NORTHERN CAMEROON

This chapter documents cowpea production and storage in northern Cameroon.
The first section describes cowpea production and extension in the Far North Province.
The second section describes the technical research devoted to cowpea improvement.
The third section describes the 1990 00me production and storage survey conducted by

a Purdue University research team.

3.1 Cowpea Production and Extension in Northern Cameroon

Cowpeas, the principal gain legume crop in northern Cameroon, are cultivated
for leaves, gain and hay. Households harvest geen leaves daily from July through the
end of the rainy season, harvest geen pods as vegetables from mid-July to early August
and harvest dry pods beginning in late September to early October. Although cowpea
production accounts for only 5% of the harvested area of the Far North Province, for
many households it fills an important niche during the ”hungy season" (July-August),
since COWpeas are practically the only "new crop" available during this period.

Cowpea production is concentrated in the Sahel and Sudan Savanna ecology of
the Far North Province. During the 1984-89 period, annual harvested area ranged from
17,000-30,000 hectares and total production from 2,211-4,560 metric tons (Table 3.1)
The large amount of year-to-year variability reported in Table 3.1 may be attributable to
weather, changes in cropping practices, and/or human error in data collection and
compilation. Because COWpeas are generally intercropped, it is difficult to reliably
estimate production. Average yields are low (300-400 kg/ha), due to insect, disease, and

fertility problems. Although research trials have produced potential monoculture yields

29

 

 

30

of 2,000 kg/ha, low resource farmers in northern Cameroon are often unable to obtain

inputs (e.g., seed and insecticide) needed to produce high yields under monoculture.

Table 3.1 Area harvested, total production, and estimated yield for cowpea, Far
North Province, Cameroon, 1984 to 1989.

 

 

 

 

 

 

 

 

 

Year Area Harvested Total Production Estimated
(Ha) (metric tons) Yield
1934 23,470 3,273 404 ‘
1985 30,232 3,118 560
1986 24,109 3,439 616
1987 16,744 2,211 424
1988 29,975 3,596 743
1989 16,998 4,560 897
mean 23,600 3,366 607

 

 

 

 

 

Source: National Directorate of the Agiculture Census, Cameroon.

Cowpeas are cultivated under diverse soil and climatic conditions in northern
Cameroon. The NCRE’s Technical Liaison Unit classified the Far North Province into
three major production-system zones (Figure 3.1 and Table 3.2).

The most traditional COWpea farmers are found in the mountainous regions of
Zone 1. Typically, they intercrop local cowpea varieties with either sorghum or millet
and apply no insecticides. In contrast, farmers in Zones 2 and 3 are more likely to have
adopted improved farming practices-including monocropping of improved cowpea

varieties and insecticide sprayings.

 

31

 

 

 

 

 

 

 

Figure 3.1 Map of the Major Production-System Zones of the Far North Province,

Cameroon

 

32

Table 3.2 Major Production-System Zones, Far North Province, Cameroon.

Zone 1

Major crops: sorghum, millet, cOWpea, peanuts

Minor crops: fonio, souchet, eleusine

Rainfall: > 800 mm

Soils: shallow plateau soils and steep mountain slopes, erosion
Cultivation: intensive terracing

Animal traction: seldom used

Population density: 80/km2

Ethnic goups: Mafa, Mofou, Kapsiki

Zone 2

Major crops: sorghum, cotton, peanuts, cOWpea
Minor crops: sesame, eleusine, fonio

Soils: deep erodic sodic soils

Rainfall: 700-800 mm

Animal traction: seldom used

Ethnic goups: Mofou, Kapsiki

Zone 3

Major crops: cotton, sorghum, cowpea, peanuts
Minor cr0ps: okra, sesame, fonio; dry season sorghum
Soils: loamy soils, level vertical lowlands

Animal traction: oxen used by 25-30% of farmers
Ethnic goups: Fulbe, Guiziga, Toupouri, Kotoko

Note: Minor crops listed in italics do not have an equivalent name in English.
Source: NCRE (1990).

Farmers in these zones are more likely to use improved COWpea technology because they
gow cotton as a cash crop and thereby receive inputs and extension services from the
cotton parastatal, SODECOTON. Also, SODECOTON staff devote approximately 10%
of their time to providing extension services for food crops (i.e., maize, peanuts, COWpea,
sorghum) and posts an extension agent (moniteure), in every cotton farming village. In
addition, about 0.2% of the farmers participate in on-farm trials run by IRA, and receive
seeds, inputs, and extension services, in exchange for their participation. In contrast,
although the extension branch of the Ministry of Agiculture (MINAGRI) also provides

extension for food crops, these agents are centrally located and are expected to go out to

 

 

33

the farmers. Thus, cowpea farmers outside of the cotton villages receive minimal
extension support in the Far North Province (Stems, 1993).
3.1.1 COWpea Consumption and Utilization

Several parts of the cowpea plant are used by the household. COWpea leaves are
an important food item for many households, which are commonly consumed as a
vegetable, both geen and dry. In fact, some farmers plant local COWpea varieties
specifically for their high leaf yields. According to Wolfson, “leaf consumption was so
important for many households that they went out of their way to provide themselves
with leaves to use as a geen vegetable" (Wolfson, 1989). Frequently, farmers who
planted monoculture COWpeas and sprayed also intercropped cowpeas with sorghum in
order to have insecticide-free cowpea leaves to eat. Other farmers reported that they
consumed leaves that had been sprayed, but only after a certain number of days had past
and the leaves were considered safe to eat. Cowpea leaves are also sold in local
markets, at an average price of 35 CFA/kg (1984-1998) (Stems, 1993).

COWpea hay, an important forage resource for most households, is used for
animal feed, while some also sell it in local markets at an estimated average annual price
of 25 CFA/kg (1984-1998) (Sterns, 1993).

COWpea gain is both home consumed and sold. About 24 percent of the Far
North Province’s cowpea gain production was sold (Census of Agiculture, 1987).
Under normal rainfall conditions, average annual price for ma gain is 155 CFA
(Stems, 1993). Available data suggests a strong relationship between the gender of the
person(s) responsible for cowpea production and their market orientation. According to
Wolfson (1989), "when women are responsible for production, the primary purpose is

always for consumption."

 

 

TEE

34

3.1.2 Cowpea Research in Northern Cameroon

Research on cowpeas is conducted by the Institute for Agonomy Research
(IRA) within the Ministere dc I ’Enseignement Superieur, de I ’Infarmatique et de la
Recherche Scientifique (MESIRES). The agicultural research system is organized along
major ecological zones, with one research center per zone. The Maroua center
addresses production constraints for the principle cash and food crops of northern
Cameroon-cotton, cowpea, millet, peanuts, and sorghum. The COWpea unit screens
varieties, identifies and tests improved post-harvest storage technologies, and has
recently initiated breeding to develop high-yielding cowpea varieties with resistance to
storage pests. The research system is funded jointly by the Cameroonian government
and donor projects. USAID’s National Agriculture Research Project, implemented
through IITA, has provided $46.7 million (1979-1994) through the Nation Cereals
Research and Extension Project (NCRE) to support the agicultural research system,
including COWpea research at Maroua. Over the period 1981-1992 the Bean / COWpea
Collaborative Research Support Project (CRSP) has provided $1.97 million through the
Maroua center2 (Sterns, 1993). .

The research system in northern Cameroon employs an on-farm testing approach
as a means of linking research to extension. In 1986, on-farm testing was
institutionalized into the national agicultural research system when the National Cereals

Research and Extension Project (NCRE) provided the impetus for the creation of the

 

"The NCRE progam supports research throughout Cameroon, whereas the CRSP
research is conducted only through the Maroua Center (Stems, 1993)".

 

35

Testing and Liaison Units (TLU’s) at four of IRA’s research stations, including the
Maroua Center3 (Stems, 1993).

The International Institute of Tropical Agiculture (IITA) works with host
country institutions (IRA) and the CRSP to conduct varietal screening trials in
Cameroon. Similarly, the Semi-Arid Food Grain Research and Development project
(SAF GRAD) organizes varietal screening trails, which are conducted primarily on-farm
but also at the research station in Maroua.

The first improved cowpea technology developed by the Maroua station was a
package that included an improved cowpea variety, TVX3236 0G1 and a set of
improved management practices. "This indeterminant, medium cycle (75 to 80 days to
maturity) variety was selected from IITA regional screening trials for its high yield
potential, gain color, and insect (thrips) resistance” (Stems, 1993). Farmers were
advised to monocrop the variety on a quarter hectare plot and apply 2-3 insecticide
sprayings as needed.

Through the SAFGRAD on-farm testing progam, TVX3236 was first gown by
farmers in 1980, although wide-spread extension of the variety did not begin until 1984.
The "TVX package” continued to be recommended and extended through the 1987
gowing season. Later, ”Ife Brown (a local Nigerian cultivar) and WA (a local
Cameroonian cultivar from the Moutourwa area) were added to the farmers’ choice set
for improved varieties in 1985 and 1986-1987, respectively” (Stems, 1993).

During the period 1980-1986, researchers and extension workers documented

significant post-harvest storage losses due to bruchid infestations. As a result, the

 

3Farmers participating in on-farm trials run by IRA receive seeds, inputs, and
extension services.

 

36

Ministry reduced the recommended plot size from a quarter to an eighth of a hectare,
the contention being that until the storage constraints could be relaxed, farmers should
focus on gowing cOWpeas as a garden food crop, rather than a cash gain crop. Sterns
points out that Ministry of Agiculture and IITA researchers were at odds over this, in
part, because in 1987 two new sister varieties from HTA were extended with several
advantages over TVX3236: comparable yield, larger gain size, significantly less
shattering of seed pods, and more importantly, geater resistance to bruchids. Available
evidence suggests that these two varieties, BR] and BR2 (IITA cultivars IT81D-985 and
IT81D-994, respectively) were sufficiently resistant to bruchids to allow an additional one
month of storage before bruchid damage became significant.

Summarizing the research and extension thrust since 1987, Stems reports that
”since 1987, researchers have continued to advise farmers to plant cowpea as a monocrop
in quarter-hectare plots sowing BRl and BR2 and applying 2 to 3 insecticide sprayings”
(Sterns, 1993 p.39). They have also initiated two projects to address the storage
problem: (1) a breeding progam targeting, in part, bruchid resistance; and (2)
development of low cost storage technologies which reduce or eliminate bruchid damage.

Table 3.3 details the chronology of Maroua’s cowpea extension recommendations.

3.2 The Bean/COWpea CRSP/IRA Cameroon Project

The Bean/COWpea CRSP began work in northern Cameroon in 1982, in
affiliation with two host institutions, IRA and the regional cotton parastatal
SODECOTON, and with the on-going SAF GRAD project. During the early years, the

CRSP research focused on agonomy/pest management.

 

 

37

 

 

 

 

 

 

 

 

 

 

 

 

Table 3.3 Extension Recommendations for COWpeas Northern Cameroon, 1984 to
1991.
Years Extended
Extended Technologies 1984 1935 1986 1987 1988

1991
Monocropped COWpeas "‘ *" *u "t tn an:
Insecticide sprayings ‘** *1" in" an ”a: was
1/4 ha "block" plot an: use see sun can sass
1/8 ha "garden” plot as" am u.
Variety TVX 3236 ”* "W 3*"
Variety Ife Brown ***
Variety VYA at": sea sane sass
Varieties BR] and BR2 um um ann-

 

 

 

 

 

 

 

 

 

""*" denotes the years in which the improved technology was extended to farmer.
Source: Stems (1993).

In 1987, the IRA/CRSP Project initiated a gain storage project designed to
address the problems of insect-caused post-harvest losses in COWpeas. The project’s
research objective was to devise acceptable and simple storage technologies to reduce
losses to storage pests. In collaboration with IRA and NCRE scientists, Dr. Jane
Wolfson conducted three surveys in major cowpea gowing areas of the Far North
Province to better understand farmers’ COWpea storage methods and assess insect
infestation in stored cowpeas. During the first survey (1987), 38 COWpea gowers were

interviewed. The second survey (January 1989) involved 131 interviews within 112

 

38

households. The third survey (March 1990) was conducted in 15 anondissementt
(districts) where 117 households were interviewed‘ (Figure 3.2).

Two major conclusions from these surveys were that women have the primary
responsibility for storage in most households, and that cowpea storage is generally a

processuthe crop is moved at least once at some time during the storage season.

 

Insights gained from these surveys served as the basis for the subsequent research
agendas and were used to develop new appropriate storage technologies.

As the IRA/CRSP Project evolved from an emphasis on agonomy/pest

 

management to its current focus on post-harvest storage losses of cowpea, the project’s
breeding initiative was redirected to develop varieties resistant to storage pests,
specifically Callosobruchus maculatus. Results from the surveys and technical research
served to guide the breeding strategy. First, the surveys found that farmers in the Far
North Province generally stored 00qu in pod form for some period of time before
threshing. Second, experiments found that cowpea pods can provide a substantial degee
of protection against cowpea weevil, as long as the pod wall remains intact. Third,
research showed that rough-seeded cowpea types provided substantial resistance to
Callosobmchus maculatus. These results contributed to establishing the selection and
breeding criteria for improved COWpea varieties: 1) combined seed and pod resistance to
Callosobruchus maculatus; 2) non-dehiscent, breakage-resistant pods; 3) stable and higher

yield under low input conditions (both in association and as monocrop); 4) dual purpose

 

‘Although 117 households were sampled, 135 samples of cowpea gain were collected
because some households gew more than one COWpea variety. If a farmer gew several
different varieties or stored their cowpeas using different methods, more than one gain
sample was collected.

39

.Wm

O Kolofata
O Mora

Koza
To . bare

. =2§=,%22~ M ti
0 Mokolo ‘ 0 Born

OMaroua
OMindif

I Moutourwa

. .G'l’ .
Knob

 

Figure 3.2. Map of Surveyed Districts (March 1990), Far North Province, Cameroon.

 

40
«acceptable forage as well as gain yield; 5) acceptable gain quality (size, color, texture,
and taste); and 6) acceptable leaf quality for sauce (CRSP, 1991).

Since the mid-1980s, the IRA/CRSP project has conducted varietal trials
designed to identify agronomically stable cowpea lines adapted to specific areas with
tolerance to major insect pests and diseases. These trials have served as a basis for
recommending varieties, as well as selection of parental material for on-going breeding
efforts. Since its inception, the project has developed cowpea screening methods to
evaluate resistance to storage insects, specifically Callosobruchus maculatus. Beginning in
1990, scientists sought to expand farmer participation in varietal improvement by
modifying the way it conducted variety trials. Under the revised protocols, selection of
breeding materials and varieties are based on research and farmer evaluations, rather
than on yield trials alone. Research evaluations include ratings of virus resistance, pod
breakage characteristics, and seed and pod resistance. Generally, material which appear
promising in the field to researchers and farmers alike, are then screened for seed and
pod resistance (CRSP, 1990).

3.2.1 CRSP Storage Technologies

The second component of the IRA/CRSP project focused on developing and
evaluating simple storage technologies to reduce post-harvest storage pest losses--
including improved bagging, storage with botanicals and ash, earthenware containers, and
a solar gain heater.
3.2.1.1 Storage in Ash
Overview

Ash storage is commonly used by cowpea gowers in northern Cameroon

(Wolfson, 1987). Analysis of this traditional technology by CRSP/ IRA researchers found

 

41

that when mixed with ash and tightly packed, bruchid larvae will continue to develop and
will pupate within the seeds as usual. However, when the adults attempt to emerge,
most will have difficulty escaping from the seed and insects that successfully emerge will
then have difficulty escaping from the ash.

Farm surveys found that farmers mix ash and cowpeas in various ratios. Yet,
laboratory trials found that the optimal ratio of wood ash to cowpeas (i.e., maximum
bruchid control) is 3 volumes of ash to 4 volumes of cowpea. Also, since female bruchids
ready to oviposit will not dig downwards into ash, it is recommended that farmers cover
the stored COWpeas with a 3 cm layer to prevent re-infestation. Finally, trials showed
that all types of wood ash are equally effective.

Procedure

Based on these research results, scientists recommend that farmers follow the
following set of protocols to improve the effectiveness of ash storage.
1) Gather enough wood ash to mix with 50 kg COWpea seed.

2) Sift ash to eliminate large particles of charcoal.

3) Mix cowpea seed with equivalent volume of ash, at a 1:1 ratio, in a large mixing
bowl.

4) Pour ash mixture into a large cannary.

5) After each addition of ash and COWpeas, compact the mixture with open hands to

remove air pockets.
6) When the cannary is full, cover the stored gain with a 3 cm layer of ash.

7) Each time that cowpeas are removed from the cannary, restore the ash cover.

 

42
Labor: Begurr' ements

According to Kitch, labor requirements for ash-storage of 50 kg of threshed

cowpea seed are:

gather wood ash (50 kg), 30 minutes
sift out large particles, 60 minutes
mix and pour into cannary, 30 mm utes
total 2 hours

W

The only material required is a cannary.
0 clay cannary (1 unit @ 1,500 CFA/unit) = 1,500 CFA

Depreciation

The estimated useful life of a cannary is 5 years.

3.2.1.2 Triple Plastic Bags
Overview

Storage in airtight containers is an effective method to eliminate Callosobruchus
maculatus populations because they require oxygen to survive. Because clear plastic bags
(50 kg capacity) are available in northern Cameroon, the project tested their
effectiveness as airtight containers. Since plastic bags are easily punctured, the IRA-
CRSP project suggests using three plastic bags, placed one inside of the other and
individually sealed to achieve airtight conditions. To effectively control bruchids, these

plastic bags must remain sealed for at least 3 months’.

 

’I'his storage method is intended for mid to long term storage. It is recommended
that the triple bags remain sealed for a minimum period of two months.

 

43
Procedurg

Based on these research results, scientists recommend the following set of protocols:

1) Fold back the top of the first bag.

2) Place the second bag inside the first bag - then fold the top of the second bag
over the first. Repeat for third bag.

3) Fill the inner-most bag with COWpea seed, being careful to shift or rock the bags
frequently to eliminate air pockets. Fill the bag close to capacity, leaving only
enough room for the plastic bags to be tightly drawn together, folded back on
themselves, and tied together with a cord.

4) Draw together the top plastic of the inner-most bag, squeezing tightly to press out
the air. Gently rock the bag to eliminate any air pockets. Seal the bag with
string or cord, twist the remaining plastic above, fold this back on itself, and tie
with cord.

5) Repeat this tying procedure individually for each of the three plastic bags.

Labor Requirements

The plastic bag has a capacity of 50 kg of threshed cowpea gain. Kitch estimates labor

requirements to be:

0 fill plastic bags, 30 minutes

Capital Requirements

The only material required are three clear plastic bags:

0 3 plastic bags (1 unit @ 150 CFA/unit) = 450 CFA

Depreciation

The estimated useful life of a plastic bag is 1 year.

 

3.2.1.3 Solar Heater Technology
Overview

At Purdue University, CRSP scientists discovered that brief exposure to
temperatures of 65 C° for 5 minutes kills 100% of all stages of C. maculatus. If the
period of exposure is extended to one hour, a temperature of only 57 C° will kill all
stages of the cowpea weevil.

In Cameroon, IRA/CRSP scientists devised a simple solar heater made of two
sheets of plastic sheeting and an insulting ”mattress” of threshed COWpea pods placed
between a heat-absorbing sheet and the earth. Several different materials were tested as
underlayers, including black cotton burlap, white cotton cloth, blue cotton cloth, brown
burlap, beige burlap, and black plastic. Regardless of the underlayer materials,
sufficiently high (over 60° C) temperatures were reached and no bruchids survived any
of the treatments (Table 3.4).

To prevent reinfestation after disinfesting the cowpeas, IRA/CRSP researchers
recommend storing the gain in clear plastic bags (one or two bags placed one inside the
other) and sealing them with twine; or placing the gain into a clay cannary or ganary
(traditional storage structure covered by a thatched roof) and covering the gain with a
2-3 cm layer of ash.

Solar treatment is especially promising because it eliminates both B. atrolineatus
and C. maculatus populations on COWpea seed, without affecting germination and cooking
time.
hocedure

Based on these research results, scientists recommend the following set of protocols:

 

Table 3.4

1)

2)

3)
4)

5)

6)
7)

8)

45

Results of solar heater treatments on emergence of cowpea weevil by type
of underlayer materials.

 

 

 

 

 

 

 

 

 

Underlayer materials 1 Temp. attained within seeds‘, No. emerged

C° adults

Color Fabric Mean Range Mean
Black Cotton 76.8 63-84 0.0
Plastic 76.2 54-89 0.0
Burlap 74.1 57-79 0.0
Brown Burlap 72.5 58-81 0.0
White Cotton 69.7 61-76 0.0
Beige Burlap 66.7 54-74 0.0

 

 

 

 

 

 

 

‘After 100 minutes of exposure.

Source: Murdock and Shade (1991).
Place an insulating mattress of dried weeds or gass (3m x 3m area and 4-5 cm
thick) on the soil surface.
Place the 3m x 3m sheet of black plastic (two 3m x 1.5m sheets sewn together)
directly on the insulating mattress.
Spread cowpea seeds (50 kg) out evenly on the black plastic surface.
Cover the cowpea seeds with a 3m x3m sheet of clear plastic.
Fold together the edges of the black plastic and the clear plastic covering to
prevent air circulation around the seeds.
Place small stones on the folded edges to seal the seeds into a "plastic envelope".
Treat the seeds for at least 2 hours around midday.
To prevent re-infestation, store the COWpea gain in either clear plastic bags, a
cannary and covered with 3 cm of ash, or a ganary and covered with 3 cm of

ash.

46
Labo; Eggug' emepts
The solar heater has a capacity of 50 kg of threshed COWpea per batch. Kitch (as per

phone conversation) estimated labor requirements to be:

0 construct heater, 30 minutes
solar treat gain, 1 hour

' bag grain. sum
total 2 hours

Capital Regug' ements

Materials required to construct the heater include:

0 black plastic (6m @ 800 CFA/m2) = 4,800 CFA
0 clear plastic (3m @ 700 CFA/m2) = 2,100 CFA
0 sewing charges; and = 500 CFA
0 cannary (50 kg capacity @ 1,500 CFA/unit) = 1,500 CFA
OR
0 plastics bags (3 bags @ 150 CFA/bag) = 450 CFA
Depreciation
Estimated useful life of these materials are:
0 solar heater, 2 years

cannary, 5 years
0 plastic bags, 1 year

3.2.2 On-Farm Demonstration Results

On-farm, farmer-participation demonstrations (1990-1991) were conducted to
evaluate the alternative storage technologies. Table 3.5 presents the results of the
demonstrations of the various treatments in terms of the number of C. maculatus adult
emergence holes/ 100 seeds. Storage losses averaged only 4% when gain was first
treated using the solar heater technology and then stored in triple plastic bags. Farmer
feedback on the potential usefulness of the solar technology included the suggestion that
the solar heater materials could be purchased and used communally by 5 to 10 farmers.

Farmers concerned about seed germination following the solar treatment were informed

 

47

that research results showed no significant effect. In response to concerns about post-
solar heater treatment storage, farmers were told that they must take measures to
prevent subsequent re-infestation (e.g., store treated seeds in cannaries or ganaries
covered with a layer of ash).

Under the triple bagging technique, losses averaged 3%, slightly lower than the
solar plus triple bag technology. Yet, due to the small number of replications (2) for this
treatment, these results are not statistically different from solar plus triple bagging. Also,
since it is technically impossible that triple bagging alone could result in lower losses than
solar plus triple bagging, it is assumed that these two technologies are equally effective.

Improved ash storage was almost as effective in limiting the number of
emergence holes as the solar heater plus triple bagging treatment-storage losses for the
ash treatment averaged only 6%.

In contrast, under the double bagging treatment, losses averaged 9%--possibly
due to punctures in the bags which broke the hermetic seal.

Finally, under the control 154 emergence holes were found in the sample of 100
seeds-suggesting 100% loss when COWpeas are stored unprotected in burlap bags for
approximately 3 months or more. While some farmers store COWpeas in cloth sacks, data
collected by Wolfson suggests that farmers using cloth sack storage incurred losses
averaging only 14%, after 4-6 months of storage‘. This discrepancy may be due to
differences in the way farmers process and store COWpeas in cloth sacks, compared to the

protocols followed for the control.

 

‘Analysis of cOWpea gain samples collected from farmers who reported storing
cowpeas in sacks.

 

48

Table 3.5 On-Farm Demonstrations of Improved Storage Technologies, Northern
Cameroon,“ 1990-91.

 

 

 

 

 

 

 

 

 

 

 

 

 

Treatment“)
Village Rep Control Improved Double Triple Solar
(Sack)“’ Ash only Bag only Bag only Heater and
Triple Bag
Gatouguel 1 334 0 9 --- 5
2 -- 2 9 --- 6
Zouaye 1 89 3 --- --- 1
2 --- 6 --- --- ---
Djoulgouf 1 73 10 --- 6 5
2 --- 11 --- --- 5
DJJingliya 1 118 11 --- 0 2
Mean 154 6 9 3 4
Range 73-334 0-11 9 0—6 1-6
Reps 4 . 7 2 2 6

 

 

 

 

 

 

 

 

 

(a) Number of C. maculatus adults that emerged (i.e., as indicated by holes in seeds) in
samples of 100 cOWpea seeds receiving different storage treatments, after approximately 3

months in store.

(b) -- indicates that the respective treatment was not treated in the respective village.

(c) The control involved placing cowpea seed in a 50 kg burlap bag without and protective
treatment. This control is not however, indicative of the storage practices followed by most
cowpea farmers in northern Cameroon.

49

3.3 Cowpea Producer Survey

In an effort to generate information to help focus the technical research project,
the project sponsored several farmer surveys.

The preliminary survey (November 1987) found that most COWpea farmers both
stored cowPeas intended for use as seeds for the next year’s planting, kept gain to meet
their household needs, and if their production is sufficient to meet the household’s
consumption needs, sold the surplus. Farmers cited losses from storage pests as a major
problem.

The second survey (January 1989) found important gender differences in COWpea
production methods, utilization, and storage techniques between the households
interviewed. Women cowpea producers generally intercropped their COWpeas without
using insecticides. Whereas, men generally monocropped and about one-half used
insecticide. Women gew COWpeas primarily for home consumption and were more likely
to be responsible for storing COWpeas intended for home consumption, while men
primarily sold the COWpeas they produced. When men were responsible for storing
cowpeas intended for home consumption, they used insecticides to help preserve
cowpeas more often than women.

A third survey was conducted in March 1990, during which 117 households were
interviewed’. The survey sample was distributed around the villages of Maroua,
Mokolo, Kaele, south of Maroua towards Figule, near Mora, around Meri and towards
Waza (Figure 3.2) which represented the three major cowPea production-system zones of

the Far North Province (Table 3.2).

 

7While 117 households were interviewed, 135 gain samples were collected. If a
farmer gew several different varieties or stored their cowpeas using different methods,
more than one gain sample was collected.

 

 

50

The procedure used to select the sample of farmers to interview differed by
location“. First, in the large cowpea-producing areas IRA staff contacted cowpea
farmers or made arrangements for a contact person to introduce them to farmers, prior
to the arrival of the survey team. Second, in villages with an established relationship
with the CRSP, the team went directly to a village dignitary who then introduced them to
cowpea farmers. Third, the team also randomly stopped along the roadside when they
saw cowpeas in storage. Finally, in villages where the team had previously conducted
surveys (1987, 1989) they both contacted farmers from previous visits and meet with new
farmers.

Interviews were conducted in 15 anondirsementt (districts). The locations,
villages and the number of households per village is presented in Table 3.6. In addition,
samples of stored COWpeas were collected from the interviewed households and assessed
for storage damage. These households had been storing
cowpeas for approximately four to six months prior to sampling”.

3.3.1 Socioeconomic Characteristics

Although the 1990 survey respondents identified themselves as belonging to one

of 19 different ethnic goups, most respondents were Mafa/Matakam (26%), Guiziga

(22%), Kanouri/Bornouwa (16%), or Moufou (8%).

 

“Since farmers were not randomly selected, statistics estimated from data collected
can not be used to estimate population parameters.

’Most farmers had moved their cOWpeas to their final storage site at the time of the
survey (4-6 months into the storage season, depending on the harvesting time).

 

51
Table 3.6 Locations in which interviews were conducted and the numbers of villages
and households within each location, northern Cameroon, 1990.

 

 

Zone Location Village (No.) Household (No.)
fine 1
Mokolo 12 19
Tokonbere 2 3
Zone 2
Hina 4 8
Koza 10 20
Meri 7 10
Zone 3
Bogo 2 5
Figule 2 6
Guidiguis 4 7
Kaele 3 5
Kolofata 4 5
Maroua 4 1 1
Mindif 2 4
Mora 5 7
Moutourwa 2 3
Waza 2 5
Total 65 1T7—

Source: Wolfson (1990).

Household size ranged from 1 to 961°, with a mean of 12. The household
generally consisted of a male head of household, his wife (wives) and their children.
3.3.2 Farm Characteristics and Management Practices

Sampled cowpea farmers (1990) followed a variety of production methods. While
some farmers used only traditional technology, others used improved varieties and/ or
production recommendations extended by the research-extension system (Table 3.7).

Traditionally, COWpeas are intercropped with cereals in northern Cameroon.

Among the sample, most of the respondents (64%) intercropped their COWpea, although

 

1‘The household of one chief included 30 wives and a total of 96 people. The next
largest household included 54 people.

 

 

52

28% monocropped, and 8% plant some to both cropping patterns. Compared to farmers
who intercropped, monocropping farmers planted larger hectarages (0.92 ha vs 1.24 ha)
and harvested three times as much gain (82 kg vs. 249 kg); while farmers planting both
cropping patterns cultivated as much area (1.27 ha) as monocrop farmers, but one-half as
much gain (138 kg). On intercropped fields, COWpea yields averaged 144 kg/ha (ranging
between 6 to 1000 kg/ha), compared to 327 kg/ha (ranging between 22 to 800 kg/ha) on
monocropped fields, and 120 kg/ha (ranging between 3 to 240 kg/ha) on farms both
intercropping and monocropping.

Of the total sample, only 17% plant improved varieties. Generally, farmers
monocrop improved cowpea varieties (41%), but 7% intercrop them. Among farmers
who used both cropping patterns, 18% planted improved varieties, but it is not known if
they are monocultured or intercropped.

Most farmers surveyed did not apply insecticide (71%), but usage varied between
cropping systems. While 62% of the monoculture farmers use insecticide, 27% of
farmers planting both cropping patterns, and only 15% of intercropping farmers applied
insecticides. Of those farmers who do not spray insecticide, 54%
stated that they were not able to obtain insecticides and 16% did not spray because they
face a cash constraint.

Generally, fields with yields geater than 200 kg/ha tended to be monocropped
and sprayed with insecticide, whereas fields with yields less than 200 kg/ ha tend to be

intercropped and not sprayed with insecticide.

Table 3.7

53

farmers, northern Cameroon, 1990.

 

 

Farm characteristics and management practices of sampled cowpea

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Characteristic of Cropping Pattern
the Cowpea
Enterprise
Statistic Intercrop Mono- Both Total
(64%) culture (8%) (100%)
(28%)

Area (ha/farm) mean 0.92 1.24 1.27 1.05
(SD) (1.2) (1.2) (0.6) (1.2)
range 0.13-8.25 0.13-5.0 0.5-2.0 0.13-8.25

Production mean 82 249 138 134
(kg/farm) (SD) (88.6) (323.0) (74.3) (198.8)
range 4-500 18-1850 6-240 4-1850 pl
Yield (kg/ha) mean 144.3 326.5 119.8 200.3
(SD) (194.4) (222.3) (95.5) (215.7)
range 6-1000 22-800 3-240 3-1000
Use MVs (%) 7% 41% 18% 17%
Use Insecticide 15% 62% 27% 29%
(%)

Household size mean 11 17 13 13
(SD) (12.9) (13.0) (7.8) (12.8)
range 1-96 2-54 1-30 1-96

 

 

Source: Computed from data collected by Wolfson (1990).

54

3.4 COWpea Farmer Categories and Characteristics

Social scientists investigating the adoption process seek to classify farmers into
farmer types, ranging from non-adopters to full adopters of new technology. Following
this paradign, the surveyed cowpea farmers were gouped into three adoption types--
non-adopters, moderate adopters, and advanced adopters-based on his or her adoption
level of improved production practices (Table 3.8).

”Non-adopters” (47%) are defined as farmers who plant only traditional varieties,
generally intercropping them with either sorghum or millet, and do not apply field
insecticides“. "Moderate adopters” (31%) are defined as farmers who practice
a combination of the improved package recommendations and the traditional production
methods. In contrast, ”advanced adopters” (22%) are defined as farmers who have made
a serious attempt to adopt the recommended improved package12 (i.e., monocropped,
quarter-hectare plots of an improved variety [BR1, BR2, WA or TVX3236] and apply
insecticide).

Cowpea production responsibilities differ among households. In some
households, men are primarily responsible for the production; in others, women are the
primary producers, while in others, the responsibility is shared. Households where
women had primary responsibility for cowpea production are mostly ”non-adopters". In

contrast, "moderate” and ”advanced” adopters tend to share production responsibilities

(Table 3.8).

 

uFarmers planting traditional varieties do not apply insecticides, in part, because for
these households, cowpea leaf consumption is an important part of their traditional diet.

l"‘Some "advanced adopters" do not spray their COWpea plot with insecticide because
they face either a cash or availability constraint. It is assumed that if these constraints
were removed, they would apply insecticide. And some monocrop and apply insecticide
to traditional varieties.

55
”Advanced adopter" households tend to be large, averaging 19 members,

compared to "moderate adopter” households which average 13 members, and "non-
adopter” households which average 10 members (Table 3.8).

Farm characteristics differ among the three categories of households. ”Non-
adopter” households plant the smallest area (an average 0.7 intercropped) to COWpea and
harvest only 82 kg/household. In contrast, "moderate adopter” households plant on
average 1.3 hectares and harvest 96 kg (28% of these households monocrop); and
"advanced adopter" households plant on average 1.3 hectares and harvest 287 kg (84%
monocrop”) as shown in Table 3.8.

Institutional access (i.e., extension and inputs) appears to be associated with the
adoption of improved varieties and production practices. "Advanced" and "moderate"
adapter farmers tend to live in zone 3, and are more likely to have access to extension
services and inputs, either through SODECOTON or IRA, compared to farmers in zones
1 or 2. While "non-adopter" farmers live in all three zones, the majority of farmers in

the mountainous regions of zone 1 are "non-adopters”.

3.5 COWpea Storage

In Cameroon, COWpeas are generally harvested in mid-to-late October after the
pods have ripened and dried on the vine. To protect cowpea from bruchid damage
(Callosobruchus maculatus)--the most common COWpea storage pest--farmers have

developed a variety of traditional storage treatments and structures.

 

13Some advanced farmers intercrop improved cowpea varieties with cotton.
Insecticide applied to the cotton provides protection to the COWpea crop.

56

Table 3.8 Characteristics of cowpea farmer types, based on adoption level of
improved production practices of survey respondents, northern Cameroon,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1990.
TYPE OF FARMER (N=117)
Characteristics Non-Adopter Moderate Advanced
Adopter Adopter
Percent of Respondents 47% 31% 22%
Social Characteristics
Household size 10 (8) 13 (8) 19 (16)
mean (median) (SD)' (11.9) (14.5) (10.9)
Genderb (F/M/B%) 44/3/53% 18/13/69% 13/13/74%
Farm Characteristics
Area (ha/farm) 0.7 (0.5) 1.3 (0.63) 1.3 (0.85)
mean (median) (SD) (0.6) (1.7) (1.1)
Production (kg/farm) 82 (50) 96 (75) 287 (228)
mean (median) (SD) (87) (89) (340)
Yield (kg/ha) 150 (68) 159 (96) 343 (320)
mean (median) (SD) (228) (172) (198)
Cropping Practices
Monoculture (%) 0% 28% 84%
Insecticide (%) 0% 28% 93%
1/4 ha plot (%) na na na
Improved variety (%) 0% 15% 55%
Institutional Access‘
Zone 1 (%) 27% 13% 6%
Zone 2 (%) 34% 28% 23%
Zone 3 (%) 39% 59% 71%

 

 

 

 

 

 

'SD = standard deviation

”F = female, M = male, B = both

cIn general, Zone 1 farmers (mountain) had poorer access to institutional support

(i.e., markets and extension), compared to Zone 3 farmers (plains) who had direct
’ or indirect access to SODECOTON.

Source: Computed from data collected by Wolfson (1990).

57
3.5.1 The Storage Process“

The COWpea storage process is carried out in stages over time and space, as
shown in Figure 3.4 ‘5. The storage process begins (Stage 1) once the cowpeas are
harvested.

Typically, the harvested cowpea pods are sun dried before being threshed and
stored (Stage 2). Most farmers first place the COWpea pods on a drying structure called a
”danki"-- an unprotected rectangular platform, raised 6-7 feet above the gound and
supported by a wooden framework (Figure 3.3 [a]). Farmers reported that they stored
their cowpeas on the danki from one week to over six months. Prolonged danki storage
is likely due to a labor constraint. While 16% of this subset of farmers had treated their
cowpea pods while still on the danki (3% ash, 7% herb, 3% insecticide, and 3% other),
most farmers (84%) had applied no insecticide control treatment. Since many farmers
transplant mouskwari sorghum, a very important crop for food insecure households, at
the same time as when COWpeas are harvested, a shortage of labor likely delays more
rapid threshing and storage.

When time permits, farmers remove the COWpeas from the danki and usually
thresh the crop (Stage 3). Threshed gain is used for immediate consumption, sold, or
moved into a more permanent second storagesite.

Grain for final storage (Stage 4) is typically placed in a ganary, sacks, cannaries,

or drums. By March 1990, 32% of the respondents had moved their gain to a ganary,

 

1”This information is based on the findings of Jane Wolfson (1990), who interviewed
the household member primarily responsible for storing the household’s cowpea crop,
and asked him/her to describe the process he/ she followed when storing cowpeas.

1’The numbers enclosed in parentheses indicate the percentage of the respondents

who followed the respective storage practice, as of March 1990 when the cowpea gain
samples were collected.

58
25% to sacks, 13% to a drum, and 7% to a cannary, although 23% still stored their gain

on a danki. Once placed in permanent storage most farmers use one or more of the
following methods to protect stored cowpeas from insect pests (Wolfson, 1990):

(a) ash or ash mixed with herbs or insecticide;

(b) herb or herb mixed with insecticide, ash or water;

(c) insecticide or insecticide mixed with herbs; and

(d) other (including tobacco or roasting the gain).

Ash used for storage is derived from either cooking fires (e.g., wood and millet or
sorghum stalks) or animal dung. Herbs used include mint, mazavrik, hamas, mejevedin,
casiedm, lndiya, brumida, wad“, and tobacco. Furthermore, in an earlier survey,
Wolfson (1987) found that some farmers treat their COWpeas differently, depending on
their intended use. COWpeas selected for seed were generally treated, especially when
farmers selected next year’s seed at harvest or soon after.

Granaries, the most commonly used storage method, are large round structures
that are used for bulk storage; but vary in size, shape, and construction material by
ethnic goup. Granaries are usually divided into sections, in order to facilitate storing
several different crops. In contrast to dankis, ganaries are usually closed structures,
although their tightness depends on the ganary type (Figure 3.3 [b]).

Sack storage, the second most common storage method, involves placing gain in
burlap sacks (50 kg), which are then stored in a ganary or family dwelling. Generally,

farmers storing in sacks (25%) did not treat their gain (66%)--possibly because they are

 

l"Spelling is the transliteration of the spoken name.

59
intended for immediate sale-although about one-third apply insecticide to sack-stored
gain.

Drum storage, the third most common storage method, involves placing the gain
in a 50 gallon metal drum and sealing it with a lid. Of the households who had moved
their gain to a drum (13%), almost all (98%) applied no additional storage treatment.

Cannaries, the least used storage method, are large clay pots, measuring about 2
feet in diameter and 1.5 feet in height, which are traditionally used to store cOWpeas and
other gains. Sometimes they are sealed by placing a similar or slightly smaller cannary
on top of the mouth (Figure 3.3 [c]). Among households who had moved their gain to a

cannary (7%) ash was the most frequently used protection method (44%).

 

 

 

 

 

"323,4- r/f-a/x-raifézg if;
747' _ m! -
I." ,f
"t . i.
ii. I‘l' 'if
'- v ! a
‘.

 
  

 
   

" :1? ' - a, _ .‘ f“:.\\’~.-\“-=
.7, am) his.
’3’, ”x! ’y :' i .‘._" . ‘

. ‘ | .. l ‘ ‘

* Ai/v“! I I
. H ”I It" III
.f' N ,7

 

Figure 3.3 Traditional Storage Technologies.
Source: Wolfson, 1989.

 

 

 

 

 

 

 

 

 

 

[b] Granary

61

 

I Mil/Laue 1““ '
“all/Md ” JJl Jllfl‘”

  
       
 

f/JI/fl/y/M "
.3? «M.

 
 
  
   

Jud-L... “I‘M“ ”'1. Li
,M‘

[b] Granary

¢~:a aI?'I’ " ? .;~—"e
, r 35" I: '-

   

[c] Cannary

  
   

.' ‘ ‘r':

62

 

 

 

m
the 1: / \M
Dank!
III-2: cav\ /
Inga I: m
uno/ l \‘ eon
Imps:
/ :3. - .............,
Sack as) at" 1'8)
lnaodolda on. Ham on, Nollie
(31‘) M) m} m m
//Gnm a" mu, m
Ash Herb lnao\etleldo mm (:3) (3:; '3':
(40%) (2“) (1 4*} M)

 

 

 

Figure 3.4. The COWpea Grain Storage Process, Northern Cameroon.

Source: Estimated from data collected by Wolfson (1990).

63

3.6 Farmer Classifications and Their Storage Process

As noted earlier, the cowpea storage process is carried out in stages over time
and space. Farmers first placed harvested cOWpeas in one location for drying and then
moved to a second location at a later date. Ash treatment (or other materials) to inhibit
storage insect infestations generally occurs at the second storage site.

Figure 3.4 presents the storage process diagammatically, and notes the
percentage of respondents who followed the respective storage practices. These data
indicate the location and treatment of the households’ cOWpea harvest, in March 1990
when the cowpea samples were collected. As of March, 23% of the farmers had not yet
removed their cowpeas from the danki. While 16% of this subset of farmers had treated
their COWpea pods while still on the danki (3% ash, 7% herb, 3% insecticide, and 3%
other), most farmers (84%) had applied no insect control treatment. Generally, farmers
did not treat COWpea stored in sacks-possibly because these were intended for
immediate sale. For cowpeas placed in a ganary or cannary as the final storage site, ash
was the most frequently used treatment; followed by herb for cowPeas stored in the
ganary and no treatment for gain stored in a cannary. Where drums or other vessels
(i.e., pans) were used to store COWpea seed, 98% of the time the seed was not treated.
Analysis of household storage practices at the time of sampling by farmer classifications
(advanced, moderate, and non-adopter) showed several significant relationships (Table
3.9).

Among households classified as "non-adopters", women were generally
responsible for storage. For these households, most of the crop was either still in pods
on the danki (28%), or had been threshed and moved to a ganary (37%). Ash was the

most frequently used treatment by "non-adopters" who had moved their gain to a

64

ganary. Furthermore, "non-adopters” as a goup, almost exclusively used ash to protect
their stored cowpeas.

Among ”moderate adopter" households, the data did not show any discemable
evidence of a gender difference regarding storage responsibilities. Many (28%) of these
households still had cowpea pods on the danki; and of those households who had moved
their cowpeas from the danki, 21% stored their cOWpea gain untreated in sacks, 31%
stored in ganaries, and 18% stored in other containers including cannaries. In contrast
to the "non-adopters”, most (69%) of these households did not treat their stored cowpea
gain.

As was the case with the ”moderate adopters", the data did not show a
distinguishable gender difference for ”advanced adopter" households. By March 1990,
most advanced adopters (93%) had removed their COWpeas from the danki and placed
them into a second storage site. "Advanced adopters”, as a goup, most frequently used

insecticide (38%) in storage, primarily spraying COWpeas stored in sacks (32%).

3.7 Farm-Level Storage Losses

Foodstuff storage losses can be measured as a loss in quality, nutritional value, or
germinative ability. When evaluating storage losses at a point in time, a strict definition
of loss should be applied to assess cOWpea storage losses, if the seed is to be planted in
the following year since the cowpea’s germinative ability is destroyed approximately 30%
of the time the seed coat is damaged (Kitch interview, 1992). But if cowpeas are
intended for human or animal consumption, a less strict definition could be applied.
While one hole in the COWpea seed coat will affect the nutritional value of the seed and

may affect the food quality, this does not render the gain unfit for consumption.

65
Table 3.9 Storage Practices at the Time of Sampling by Farmer Classification.

Total Sample I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

' solely women I 32% I 38% I 58% 46%
shared by women and I 29% I 26% I 15% 21%
men
Location of Grain
(March 1990):

On danki in pod 7% I 28% | 28% 23%
In final store 93% I 72% | 72% 77%
Long Term Storage 7

Method/Treatment:

Sacks untreated 19% 21% 10% 15%
Sacks treated 32% 2% 6% 12%
Cannary with ash 0% 0% 6% 3%
Granary untreated 6% 8% 6% 7%
Granary treated 16% 23% 31% 24%
Other 20% 18% 13% 16%

 

 

 

 

 

 

 

Source: Computed from Wolfson (1990).

The only available data for estimating farm-level storage losses was collected by
Wolfson (1990) who collected samples of cowpea that the interviewed households had
stored for approximately four to six months. Each sample consisted of 50 pods (if
cowpeas had not been threshed) or approximately 400 mls of gain. These samples were
placed in cloth bags and taken to the laboratory where ten pods were evaluated for
breakage. For the pod samples, eggs laid on the pod were counted and attributed to
either Callosobruchus maculatus or Bruchidius atrolineatus according to their location on
the pod. After counting the number of emergence holes in the pods, the pods were

opened and the gains were assessed for losses. Wolfson recorded the number of gains

66

in the sample, the weight of the gains and the number of emergence holes per gain.
Then the sample was placed in a cloth bag and closed tightly. Thirty-five days later, the
sample was frozen and again assessed for losses by recording the number of holes, the
number of gains, the weight of the sample and the number and species of emerging
bruchid adults.

Bruchid populations gow exponentially over time therefore, to measure cowpea
storage losses" this study uses ”the percent of seeds with 1 or more holes" as the
operational definition for "percent loss”, calculated as:

%Loss= 100-(number of COWpeas with holes) ”00 (3.1)
total number of cowpeas sampled

 

These analyses showed that after four to six months of storage under farmers’ storage
practices, lossesm averaged 12.6%, with a standard deviation of 18.0 for all households
at the time of sampling”.

To evaluate differences in storage losses among "non-adopter", ”moderate
adopter“, and "advanced adaptor" farmers, these data were reevaluated by farmer type.
These analyses showed that the level of storage losses differed geatly among the three
farmer categories. ”Non-adopters" incurred the highest level of losses, averaging 15.3%
(S.D.= 11.9), compared to ”moderate" and "advanced” adopters who averaged losses of

10.8% and 7% (SD. = 11.4 and 17.6), respectively.

 

17Data collected from surveyed households in March 1990.
13Losses reflect the level when first collected, not 35 days later.
1"This loss level was significantly lower than the level observed in the storage trial,

where losses averaged 100% in the control (sack storage) after approximately 3 months
of unprotected storage.

67

3.7.1 Storage Losses and Farmers Field Practices

To determine if farmers’ field practices affected the level of storage losses, the
loss data were reanalyzed by practices followed (Table 3.10). First, these results
indicated farmers who had sprayed insecticides on their standing crop (N=39) had an
average of 10.3% (S.D.= 16.6), while those not spraying (N=95) had average losses of
13.7% (S.D.= 11.7) at the time of sampling. Second, storage losses and infestation levels
were associated with the cropping pattern followed. COWpeas intercropped with cotton
(N=19) had the lowest level of loss, averaging 9.8% (S.D.= 9.0)--slightly lower than
cowpeas planted as a monocrop (N=37), which averaged 10% losses (S.D.= 17.3). This
is probably due to the fact that cowpeas which are either monocropped or intercropped
with cotton were most likely sprayed with insecticide. In contrast, stored cowpeas that
were intercropped with a food crop (N=78) incurred higher losses, averaging 14.7%
(S.D.= 11.9).

Finally, there was a relationship between storage losses and the region where the
sample was collected. The highest levels of loss (13.3%, SD. = 8.0) were observed in
samples (N=24) taken from farmers living in the mountainous west and northwest region
of northern Cameroon (zone 1). In contrast, the samples from plateaus (N=41) or flat
plains (N=69), (i.e., zone 2 and zone 3, respectively) had lower levels of storage loss,
averaging 12.2% and 12.7%, respectively (SD. = 10.1 and 16.3).

Thus, these results suggest there are a multitude of compounding factors which
appear to influence storage losses and insect populations, including ago-climatic
conditions (i.e., variations in rainfall and temperature patterns), cropping pattern, the
presence of alternative hosts, and the distribution of cotton production. This last factor

may be the most significant because SODECOTON is the primary source of insecticides

Table 3.10 Storage Losses by Influential Field Practices.

68

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IL

Factor Sample Size losses (%) Standard

Deviation
Insecticide Use in Field:
Spray I 39 10.3 16.6
No spray I 95 13.7 11.7
Cropping Pattern:
Intercrop with 19 9.8 9.0
cotton
Intercrop without 78 14.7 11.9
cotton
Monocrop 38 10.0 17.3
Region:
Zone 1 24 13.3 8.0
Zone 2 41 12.2 10.1
Zone 3 69 12.7 16.3

 

Source: Calculated from Wolfson (1990).

for much of the Far North Province.

3.7.2 Storage Losses and Storage Methods

To determine if storage losses and insect infestation levels vary with the storage

method practiced, the data were reanalyzed by post-harvest treatment. Over one-half of

the cowpea samples were not treated”. Among treated samples, ash, herbs, and

insecticides were the most frequently used protectants (Table 3.11). As expected, storage
losses varied both within and between treatments. Farmers treating their store with

insecticides (N=17) achieved the highest level of protection, with an average loss of

 

2"Figure 3.4 presents the various treatments that the farmers employed and their

frequency of usage.

 

69
7.5% (SD. = 8.6), but herbs (N= 12) were almost as effective, averaging 8.2% loss (SD.

= 8.2). In contrast, storage in ash (N= 19) provided the least amount of protection
against insect losses, with losses averaging 14.7% (SD = 11.0). Interestingly, losses in
COWpea pods stored on a danki were lower than losses under storage in ash (11.8%,
standard deviation = 10.7). This may be because the COWpea pods provide resistance to
the bruchids’ penetration and the sun may inhibit insect population gowth, thus
contributing to the success of storage on a danki. These results indicate that either ash
provides minimal storage protection, or that farmers do not effectively practice ash

treatment.

Table 3.11 Storage Losses by Type of Treatment.

 

 

 

 

 

 

 

Method Sample Size Losses (%) Standard
Deviation
No Treatment 34 16.9 19.1
Insecticide 17 7.5 8.6
Herbs 12 8.2 8.2
Ash 19 14.7 11.0
Danki in pods 28 11.8 10.7

 

 

 

 

 

Source: Calculated from Wolfson (1990).

3.8 Economic Value of "Lost Grain"
The previous analysis defined loss as the percent of the sample of cowpea gain
that had been penetrated by bruchids. Yet, farmers seldom discard gain that scientists,

using this definition, would classify as ”lost". Wolfson looked at peoples’ perceptions and

70
behaviors towards heavily damaged com and found that 37% fed them to animals,

24% sold them, 24% said that they could be eaten quickly, 20% throw it away, and 7%

treat it with insecticides (Wolfson, 1987).

3.9 Summary

Cowpeas are the primary gain legume crop gown in northern Cameroon.
Several parts of the plant are used by the household. COWpea leaves, gain and hay are
both home consumed and sold. Although research trials have produced monoculture
yields of 2,000 kg/ha, average yields tend to be low (300-400 kg/ha). Part of this yield
difference is due to the fact that farmers typically intercrop COWpeas with gains, which
makes direct comparisons inappropriate. On the other hand, due to the inability of low-
resource farmers to obtain inputs (i.e., seed and insecticide) needed to produce high
yields under monoculture conditions, adoption of the high-yielding varieties is limited.

Research on cowpeas has focused primarily on developing improved varieties
with storage-pest resistance and on-farm gain storage technologies. To better
understand constraints facing farmers the Bean/Cowpea CRSP conducted three farmer
surveys which revealed several variations exist in production, utilization, and storage
methods among cowpea farmers in northern Cameroon.

Sampled cowpea farmers were classified as "non-adopters", ”moderate” and
”advanced adopters" of improved field practices for COWpea production. A large
proportion of cowpea farmers (47%) were found to plant only traditional cowpea
varieties, generally intercropping them with either sorghum or millet, and do not apply
insecticide in the field. Generally these farmers were women who produced on average

less than 100 kg of COWpeas, which are most likely for home consumption. When women

71

were responsible for storing the cowpea harvest, ash was frequently used to protect their
stored cowpeas.

Approximately one-third (31%) of com farmers practice a "mixed bag" of
cropping practices (i.e., monocropping traditional varieties without applying field
insecticides; intercropping improved varieties without applying field insecticides;
intercropping traditional varieties and applying field insecticides). These farmers were
either men or women who produced on average less than 100 kg of COWpeas, which are
most likely for home consumption.

A minority (22%) of cowpea farmers adopted improved cropping practices--
planting a monocropped improved cowpea variety and applying field insecticides. These
farmers produced on average 287 kg of COWpeas per household. These farmers, as a
goup, used insecticide the most frequently to protect their stored cowpeas.

The level of storage losses differed sigiificantly among farmers and their field
practices. The application of field insecticides was found to affect the level of farmers’
storage losses. Farmers using insecticides in their fields tended to live in the plains or
plateaus (zones 2 and 3) of the Far North Province and had lower storage losses.
Cowpeas either intercropped with cotton or monocropped had the lowest level of loss.

Storage losses also varied with the storage method practiced. Farmers treating
their store with insecticides incurred the lowest amount of storage loss and cowpeas
stored in ash received the most damage. Finally, losses in cowpeas stored on a danki
provided approximately the same level of protection as ash. This may be because
cowpea pods provide resistance to bruchids’ penetration and the sun may inhibit insect

population gowth.

 

CHAPTER 4 METHODOLOGY

4.1 Introduction

A major objective of agicultural research in developing countries is to develop
new technologies appropriate for limited resource farmers. This study focuses on
assessing the socioeconomic viability of cowpea gain storage technologies, either
developed and/ or promoted by the IRA/CRSP project in northern Cameroon, including
improved ash storage, triple bagging, and a solar heater in combination with triple
bagging.

Careful measurement of the economic benefits of these new technologies is
needed to help guide future research efforts to develop appropriate technologies that
meet the needs of limited resource farmers. This study uses the benefit-cost analysis
approach to evaluate storage technologies developed by the project.

4.1.1 Economic Concepts Relevant to Benefit-Cost Analysis

Benefit-cost analysis incorporates several socioeconomic concepts, including:
opportunity cost, discounting, changes in product price over time, input cost, economies
of scale/size, farmer implementation of technology, partial budgeting, harvest draw-down,
credit availability, and minimal acceptable return.

Opportunity Cost

In situations where households contribute their own resources to product an
output, these resources must be valued at their opportunity cost. Opportunity cost is
defined as the benefit foregone by using a scarce resource for one purpose, instead of for

its next best alternative use. Resources that are scared or limit production have a

72

 

73

positive opportunity cost. In contrast, resources that are plentiful or lack an alternative
use have a zero opportunity cost.
Opportunity Cost of Capital

Similarly, if family capital (savings) is used to purchase inputs, it must be valued
at its opportunity cost to reflect the potential income lost. Typically, the local informal
credit rate is used as a proxy for the opportunity cost of capital. Empirical studies in
Sub-Saharan Africa indicate that the opportunity cost of capital is sometimes as high as
2,273%, due to very high operating and transactions costs (Lowenberg-DeBoer,
Abdoulaye and Kabore, 1993).
Discounting Principle

Discounting is a procedure used to take into account the time value of money.
Clearly, the opportunity to earn a dollar today is worth more than an alternative that
provides an opportunity to earn a dollar tomorrow. If an investment decision affects
costs and revenues at future time periods, all costs and revenues must be discounted to
present (current) values before a valid comparison of alternatives can be made.
Typically, economists use a discount rate that is equal to the opportunity cost of capital.
For example, a $1 invested at the beginning of the year (day 1) at 20% interest would be
worth $1.20 at the end of the year (day 365). Similarly, a $1 earned at the end of the
year is worth only $0.80 today.

The general formula used for estimating the present value of a benefit stream to

be received in the future is (Gittinger, 1982):

74

V=~ R» (4.1)
n-l (Li-l)"

where V = net present value of future income

 

R = dollar amount to be received in future period n

i = rate of interest per time period

N = number of time periods covering the life of the investment
The formula can also be written as:

R1

= R2 R3 R (4.2)
(1 ”)1

+ + +,+ "

(1+i)’ (1+1): " on)"

Product Price Over Time

For most agicultural commodities in developing countries, output prices vary
considerably over the year. First, real prices may vary over several years as a result of
both supply and demand conditions and policy changes (i.e., changes in government
support prices and devaluation). Historical price data are typically used to estimate
future input and output prices. Second, over a given year, seasonality effects agicultural
prices. The price farmers receive for their crop at harvest is generally lowest because of
the abundant supply of the crop available on the market. Over time, as supply decreases
and if demand ((1,) for the crop remains strong, the price is bid up (Figure 4.1). Over
time, the supply curve shifts upward (S1 to 83) as stocks are depleted. As a result, the
market price rises from p1 to p3.
Input Cost

An input is defined as a good (such as cannaries for storing gain) or service

(such as agicultural labor) used to produce (preserve) an output such as cOWpeas.

75

.1

 

 

’1

 

7

Figure 4.1. Effects of Declining Grain
Stocks on Market Price

 

 

Maury

Economies of Size

A fundamental consideration in cost analysis is the relationship between unit cost
and volume of output. To what extent does average total cost per unit of output change
as output increases? Economies of size refers to the declining unit cost relationship that
characterizes the use of equipment, machinery, and other durable assets, that result from
spreading the fixed costs over a greater production base.

Farmer Implementation of Technology

Trials conducted by researchers typically indicate larger benefits than when the
same technology is implemented by farmers. This result is due to the observed
phenomena that farmers typically do not capture 100 percent of the potential benefits
because they do not--or are not able to-implement recommendations in precisely the
same manner as prescribed in recommendations (CIMMYT, 1988). For example, in
evaluating new technology, CIMMYT economists typically discount the experimental

yields of new varieties by 10%.

 

 

76
Experimental Control

In evaluating new technology, the potential benefits must be compared to the
benefits farmers would earn using their own technology. Thus, goss benefits to a new
technology are calculated as the difference between benefits earned by farmers using the
new technology, compared to benefits using their own technology.

In conducting on-farm trials, particular care must be paid to insuring that the
control actually represents (replicates) farmers’ typical practices. On-farm trials that
incorporate ”atypical” farmer practices (e.g., zero fertilizer as the control in a fertility
trial) will show higher returns to the experimental treatments that farmers would achieve,
if they abandoned their current practices and adopted the recommendation.

Partial Budget

A partial budget seeks to assess the value of cost and revenue items (including
opportunity cost) that change as a result of an investment decision (Gittinger, 1982).
Thus, cost and return items that do not change are ignored because they will not
influence the profitability of the technology. For example, consider the case of the
cowpea farmer who produces primarily for home consumption, may sell some of his
harvest in ‘a surplus year, and is contemplating investing in improved storage technology
to decrease gain storage losses due to weevils. In analyzing this decision, cost and
return items associated with cOWpea production may be ignored. Whether or not the
farmer should invest in a storage technology will depend on the increase in net benefits
(increased revenues minus increased costs) for each storage method, compared to his
current method.

Partial budgeting is appropriate when an activity can be added to on-going farm

processes without seriously reducing the resources available for other farm activities.

 

 

77

Since the new storage technologies to be analyzed in this study do not compete for labor
resources used in other production activities, partial budgets are appropriate for
evaluating their profitability”.
Minimum Acceptable Return

In order for a farmer to be willing to adopt a new technology, it must generate a
minimum return to his/her investment to justify the effort required (i.e., transactions
cost) both to learn and implement the new practices and compensate him/her for the
risk associated with adoption (i.e., variable performance). 7

Experience and empirical evidence have shown that farmers generally will not
adopt a new technology unless it gives a 50-100% return to his/her investment
(CIMMYT, 1988).
Stock Draw-down

Subsistence farmers, like the cowpea farmers in northern Cameroon, primarily
produce cowpeas to supply home consumption requirements until the subsequent
harvest. In addition, they may sell a portion of their crop to meet immediate cash needs
at harvest or sell gain throughout the year. A common problem facing cowpea farmers-
-both for gain stored for home use and future sales--is insect pests damage to stored
cowpeas, especially if the gain is stored unprotected. This consumption pattern has an
important impact on the farmers’ decision as to which storage method he/she will use to
protect the stored cowpea from weevil infestation. For example, if a farmer produces
only enough COWpeas to meet family consumption needs, he/she will be most interested

in a technology that allows him/ her to withdraw family food requirements on a daily

 

21Technologies that are labor intensive and compete for resources used in other
production activities are evaluated using whole farm budgeting.

 

 

78

basis. If he/she produces a surplus and has other sources of cash, he/ she may have
, geater interest in a technology that makes possible safe on-farm storage until the
market price is highest. On the other hand, if the farmer has no other source of cash,

he/ she may choose to sell at harvestuwhich requires no improved storage technology.

 

Credit Availability
Because farmers in developing countries face cash flow constraints, they typically

need credit to purchase inputs required to implement new technologies. Because credit

 

represents a cost, it must be included in estimating the returns to new technology.
Farmers may borrow money from a money lender at high interest rates (often 3-10% per
month), borrow from lending societies22 at rates varying from 0-100%, or from
institutional sources (i.e., government) at subsidized rates, typically 12% per year.
Furthermore, if credit is unavailable, they may forego purchasing the new input, even if

it is financially profitable.

4.2 Benefit-Cost Approach

Benefit-cost techniques are used to assess the financial and economic returns to
an investment (Gittinger, 1982)”.
4.2.1 Average Benefit-Cost

Average benefit-cost is typically used to compare the rate of return to two or

more alternative investments. This analysis generates a benefit-cost ratio (the present

 

22Tontines are informal credit associations in northern Cameroon, lending at rates
varying from zero to over 100% (Conversation with Doyle Baker, 1993).

23In financial analysis, inputs and outputs are valued at their market prices. In
economic analysis they are valued at their economic prices (i.e., inputs exclusive of
subsidies; outputs at border prices). If inputs are not subsidized and outputs are not
traded internationally, financial and economic analysis give the same results.

79

value of the benefit stream divided by the present value of the cost stream), which is
interpreted as the percentage increase in returns, above the investment cost. This
technique is the standard method used by the World Bank and other lending agencies to
assess the economic feasibility of alternative investments.

4.2.2 Marginal Benefit-Cost

Marginal benefit-cost analysis combines partial budgeting and benefit-cost
procedures to assess the incremental profitability of a new technology.

Marginal benefit-cost is appropriate if the analytical objective is to compare the
profitability of several alternative investments against each other. The marginal rate of
return for each investment indicates‘the additional return (%) a farmer can expect to
gain, on the average, in return for his/her investment when he/she adopts a new
technology (or set of practices), above the return from the previously most profitable
technology (CIMMYT, 1988). The differences between average and marginal benefit-
cost are illustrated by the following example.

Suppose investment A costs $20 and net returns are $40 and investment B costs
$30 and net returns are $45. The average rate of return on investment A and B would
be 200% and 150%, respectively. On the other hand, the marginal rate of return on
investment B (i.e., $30-20/$45-40) is 50%. In other words, the additional $10 required to
invest in technology B generates a 50% rate of return above investment A. Hence, if a
50% ROR is acceptable to the farmer then it would be reasonable for the farmer to
invest in technology B, otherwise the farmer should only invest in technology A.

Since marginal benefit-cost analysis is a type of partial budget analysis, it only
considers the cost of inputs (i.e., materials, labor and machinery) and the value of output

which vary from treatment-to-treatment. In the case of a storage technology, the

80
benefits (returns) are calculated by multiplying the amount of foodstuff saved (i.e., loss

reductions) times the market price per unit of output saved. The cost of the variable
inputs are determined by multiplying the amount of each input used by its market price.
0 ° a ce 's

A dominance analysis is carried out by listing the alternative investments in order
of increasing costs that vary. Any investment that has net benefits that are less than or
equal to an investment with lower costs that vary is dominated. The dominance analysis
shows that the value of the increase in net benefits (i.e., gain saved in storage) is not
enough to compensate for the increase in costs.
4.2.3 Sensitivity Analysis

A major weakness of traditional benefit-cost analysis (both average and marginal
benefit-cost analysis) is that it ignores the effects of variable outcomes. By using
"average" values for inputs, outputs, and technical coefficients, it assumes all farmers face
similar opportunities and constraints. In practice, the economic outcome of using a
technology is variable, owing to differences in farmers’ environment, resources,
managerial skills, and similar factors. Variability in outcomes introduce risk into
farmers’ adoption decisions. The geater the expected variability (risk) in outcome
around an expected net return from a particular technology, the less likely a farmer will
adopt it.

Although the expected variability is difficult to assess a priori, approximate values
can be estimated by analyzing the dispersion around the individual levels of inputs,
outputs, and technical coefficients on which the average costs and benefits figures are

based. By substituting these alternative values for the average values, sensitivity analysis

81

provides a tool for evaluating the differences in net returns associated with differing
levels of inputs, outputs, and prices that farmers may face.
W

Traditional benefit-cost analysis evaluates technologies by comparing the
profitability of each treatment, based on a single set of cost and benefit data, which
implicitly assumes that all farmers have equal access to resources (land, labor, and
capital), the same tastes and preferences, similar aversion to risk, and equal access to
credit and output markets. Based on these assumptions, a technology that gives a
sufficiently high net return is recommended to a_ll_ farmers. While the concept of
recommendation domain24 is often used to refer to farmers with similar circumstances,
this concept is seldom developed to fully reflect the way in which these differences affect
technology adoption.

Thus, traditional benefit-cost models often fail to analyze how farmer-to-farmer
differences in resources, cultural preferences and institutional access affect profitability.
Missing ”determinants of adoption” may include differences between farmer "types”
("non-adopter“, "moderate adopter", and "advanced adopter" with respect to
management practices, capacity to bear risk, access to credit and extension services, and
access to both input and output markets. These factors are considered in the following
analysis to fully assess, ex ante, the likely profitability of various gain storage

technologies to different types of farmers.

 

2“Recommendation domain refers to goups of farmers who are relatively
homogeneous with respect to resources and other circumstances.

”"Non-adopter" farmers are "traditional" farmers in the following rate of return
analysis to the improved storage technologies.

82

4.3 Factors Affecting Technology Adoption: Literature Review

The adoption of an agricultural innovation is a process comprised of learning,
deciding, and acting over a period of time (Wilkening, 1952). The decision process
begins when an individual becomes aware of an innovation’s existence and gains some
understanding of how it works. The appropriateness of an innovation is determined by
both the farmer’s socioeconomic conditions, and the technology’s characteristics. Once
the individual becomes aware of the innovation, he/ she implicitly carries out a benefit-
cost analysis (economic, social, and cultural) to assess the pros and cons of adoption,
given his/her circumstances. If the farmer decides that the benefits of the technology
outweigh the costs, the farmer adopts the innovation and continues to use it, if
subsequent use confirms his/ her initial judgement.
Factog Aflecting Adoption

Factors that affect the adoption rates for agicultural innovations have been
widely documented. At the individual farmer level, numerous studies have shown that
farm size, risk and uncertainty, human capital, labor availability, credit availability,
product and factor markets, and tenure affect farmer adoption (Feder, Just and
Zilberman, 1985; Schutjer and Van Der Veen, 1976).

Summarizing the adoption literature Coulibaly (1987) identifies two major types
of factors that affect farmer adoption of innovations:

0 The relative advantage of the innovation

0 The characteristics of the adopters

Although presented as discrete categories of factors that influence technology
adoption, it is important to keep in mind that there is considerable interdependence both

between these major categories, and between factors within each category.

83
W

The relative advantage of a new technology is defined as its advantage, compared
to alternative technologies-«including farmers’ traditional technologies. Factors that
affect relative advantage include the profitability of the innovation, its characteristics,
ago-climatic conditions, and the institutional support available to sustain farmer
adoption.

Bram

Higher profitability may be due to improved productivity (lower unit cost), better
output quality (e.g., undamaged cowpea seed), or a combination of these.

Norman (1973) found that northern Nigerian farmers allocate their farm
resources to maximize profits and food security. Similarly, Sene (1980) found that for
Senegalese farmers, profit and food security influenced technology adoption, but that two
institutional factors--the organization of production at the farm level and the internal
wage system within the householduplayed a more decisive role in farmer acceptance of
new technology. Coulibaly’s analysis of the adoption of cowpea technology (high yielding
cowpea varieties) in Mali highlights the changes in market opportunity on profitability.
Although initially profitable, widespread adoption led to increased production and falling
prices, which may make the technology no longer attractive to farmers. Farmers stated
that they would "decrease cowpea acreage to supply only their home consumption level if
the prices became depressed by the lack of sufficient markets to buy the 1986

production" (Coulibaly, p.77).

vat' aracteris 'cs

Technologies may be classified in terms of their characteristics. For example,
pest protection via resistant varieties require minimal farmers knowledge, compare to
insecticide technology. Studies have shown that the specific characteristics of the
innovationusuch as its compatibility with existing beliefs and farming practices, its
technical complexity, and the degee to which it meets a need felt by the adopters--
affects the adoption rate.
Ago-climatic Conditions

Ago-climatic conditions influence adoption through their effect on the
performance of a technology, and thus its profitability over time (risk). For example, a
given technology will perform differently in different soil types, climates, levels of insect
infestation, and disease pressures.
[pstitutiong Support

Institutional support is widely recognized as necessary for the adoption of
agicultural innovations. The main components of institutional support include access to
credit, input and output markets, remunerative product prices, and extension
information.
Credit Availability

Farmers facing a cash constraint typically require credit to adopt new
technologies. In general, capital markets in Sub-Saharan Africa are poorly developed,
and very few formal sector financial institutions serve in rural areas. A study of the
adoption of new cowpea varieties around the research station of Cinzana, Mali found
that farmer adoption of new varieties and management practices was influenced by the

availability of credit for complementary inputs (i.e., insecticide sprayer), as well as access

85
to cowpea marketing outlets (Coulibaly, 1987). Similarly, Chipande (1987) found that in

Malawi few female-headed households adopted the recommended agicultural
innovation, in part, due to their apparent inability to obtain credit for needed inputs".
Input Availability

Agicultural innovations often require timely access to inputs. In developing
countries, rural input markets do not always exist or need to be strengthened to make
inputs available to farmers when needed (Timmer, et al., 1984).
Output Markets and Prices

Remunerative market prices provide farmers with an incentive to invest in new
technology. Yet, due to high transport costs, farm-gate prices (market price minus
transport costs) are often significantly below consumer market prices--thereby reducing
profitability. Similarly, thin product markets are a major barrier to the adoption of
agicultural innovations. In regions where only a small percent of total output is
marketed, relatively small increases in outputuoften due to favorable rainfall--result in
large decreases in the market price following harvest.
Extension Access

Because new technology is often knowledge intensive, the quality and level of
extension contacts between farmers and extension agencies affects the performance of
the technology and the rate of adoption. For example, Falusi ( 1973) found that in
Nigeria, insufficient knowledge about fertilizers reduced farmer adoption of this

recommended practice (Falusi as quoted in Coulibaly, p. 22).

 

2“Because of their severe labor constraints and low average cultivated hectarage.

86
mm
All of the factors discussed above will affect the profitability of a new technology,
and thus, its relative advantage compared to farmers’ current technology. Rogers has

observed:

"...the relative advantage of a new idea must be at least 25 to 30 percent higher

than existing practice for economic factors to affect peasant’s rate of adoption.

When an innovation promises only a 5 to 10 percent advantage, the peasant

farmers may have difficulty distinguishing its economic advantage" (Rogers as

quoted in Schutjer and Van Der Veen, 1976, p. 34).

CIMMYT economists take an even more conservative perspective, arguing that
farmers’ typically require a minimum return of 50 to 100 percent to adopt a new

technology.

Frmrh rii

Personal characteristics of farmers that influence to the adoption of innovations
include: human capital, farm size, labor availability, and farm income.
Human Capital

Many studies have found a correlation between education and the rate of
adoption. Gerhart (1975) in his study of the spread of hybrid maize in Kenya, found
formal education was positively (and significantly) correlated with farmer adoption of
innovation (Gerhart as cited in Coulibaly, p. 23). Available literature suggests that better
educated farmers are earlier adopters and apply modern inputs more efficiently
throughout the adoption process (Feder, Just and Zilberman, 1985).
We

Empirical studies suggest that some modern variable inputs (especially labor-
saving technologies) are adopted most rapidly by farmers with large hectarages (Barker

and Herdt, 1978). Similarly, evidence from Africa suggests that farmers in a stronger

87

asset position (including access to land) adopted ox plowing to a geater extent than
other farmers (Schutjer and Van Der Veen, 1976). In contrast, evidence from Asia
suggest that farmers with smaller holdings adopted yield-increasing technologies like
modern varieties and insecticide more rapidly than larger land owners (Herdt and
Capule, 1983).
Qbor Availabilig

If a technology is labor intensive, the availability of household labor will influence
a farmer’s adoption decision. For example, Chipande (1987) found that a shortage of
labor constrained the adoption of improved maize varieties among female-headed
households in Malawi. The labor deficiency of these households made them credit risks
because they cannot produce a surplus which can be sold for cash to repay their credit.
Similarly, Hicks and Johnson (1974) found that the adoption of labor intensive rice
technologies in Taiwan and HYV in India (Harris, 1972) was related to the availability of
labor (as cited in Schutjer and Van Der Veen, 1976, p. 25).
W

Regarding the relationship between farmer income, asset position and willingness
to absorb risk and uncertainty, the literature suggest that low income farmers are risk
averse. Even if highly profitable "on average”, low income farmers cannot risk adopting
new technology or management practices which, because of instability of return, threaten
the existence of the farmer and his/her household (Schutjer and Van Der Veen, 1976, p.
37). Similarly, Chipande (1987) found that low income was highly associated with very

limited adoption of agicultural innovation by female-headed households in Malawi.

88

4.4 The Model

To analyze the feasibility of farmer adoption of new cowpea storage technologies,
the above concepts are incorporated in models with parameters that represent two types
of farmer situationsu'traditional' (non-adopters) and "advanced farmers. Then, the net
benefits are calculated by subtracting the total variable costs from the goss benefit for
each alternative technology. Finally, the average and marginal rates of return are
calculated. The higher the rate of return, the more likely the farmers will adopt the

technology.

4.5 Factors Affecting COWpea Storage Technology Adoption: Cameroon Situation

Socioeconomic factors which will affect the adoption of new/ improved gain
storage technologies by cowpea farmers in northern Cameroon include both factors
associated to the relative advantage of the innovation(s) and the characteristics of the
cowpea farmers.

iv v n

The relative advantage of the new/improved gain storage technologies may be
due to factors such as the profitability of the innovation, its characteristics, the ago-
climatic conditions, and the institutional support required to sustain the innovations.
Egofitabilig

The new/ improved gain storage technologies have the potential to increase
farmers’ profits by providing better quality (undamaged) COWpea gain for both home
consumption and sale. In addition, technologies that reduce losses in essence extend the

household supply of gain or make more available for future sales.

89

Storage Techpology Characteg'stics

Northern Cameroonian cowpea farmers identified storage losses due to pests as a
major constraint. Since each of the new/ improved cowpea gain storage technologies are
technologically simple and relatively easy to use, the analysis assumes that the technology
is within the capacity of all types of farmers to adopt.

MW

Cowpea farmers in northern Cameroon follow different management practices
(i.e., cowpea variety, cropping system, and insecticide spraying)--which will affect the
level of initial27 insect pest infestation of the cOWpea crop and therefore the profitability
of adopting new technologies that reduce storage losses.
113W

Cowpea farmers in northern Cameroon use various traditional storage techniques
(i.e., cloth sacks, ganaries, drums)--which affect the current insect damage level on
stored courpea gain. The less protection the traditional storage method provides the
farmer the more attractive new technologies that reduce storage losses will be.
Institutional Support
Credit Availability

COWpea farmers in northern Cameroon both face cash constraints and have very
little access to formal credit institutions. This analysis assumes (base run) that cash
constrained farmers borrow from informal credit associations (routines) at 3% per month

interest rate (based on a conversation with Doyle Baker).

 

2l'Analysis of survey data (Wolfson, 1990) showed that for the ”non-adopter” farmer,
storage losses averaged 15% of the store after 4-6 months in storage. In contrast, for the
"moderate” and ”advanced adopter'I farmer, losses averaged 10% and 7%, respectively.

Input Availability

Some of the new storage technologies require farmers to purchase materials (e.g.,
plastic sheeting and bags) only available from the Maroua market. Households living
close to the market will have better access to these inputs than households living farther
away. IRA/CRSP researchers have identified this constraint and are working toward
eliminating it by encouraging private merchants to make these materials more readily
available.

Market Access and Product Prices

Farmers who live closer to markets will receive a higher farm-gate price (i.e.,
market price less transport costs) for their cowpea harvest than farmers living farther
from the market. This price differential is not incorporated into this analysis explicitly,
because of the lack of appropriate data, yet market price will be varied in sensitivity
analysis.

The price of cowpea increases from harvest through the storage season.
Therefore, farmers who store their crop longer will receive a higher price, than if they
had sold their crop at harvest. During normal rainfall years, the market price tends to
rise from 101-113 CFA in December-March to a peak of 156-196 CFA in July-August
(Figure 5.2).

WM

Some of the new storage technologies require farmers to purchase materials such
as plastic sheeting. Farmers with sufficient cash are likely to purchase the necessary
storage materials using their own capital, but those without cash may share these
purchased inputs communally. This analysis assumed that for technologies which require

purchased materials (i.e., plastic sheeting for solar heater), cOWpea farmers will share

91

these inputs between 10 households. Furthermore, the analysis assumes that the solar
heater has an expected useful life of 2 years.
Extension Access

Although the technology is relatively simple, farmers with better access to
extension will likely incur lower levels of storage losses when using the technolog,
compared to farmers who have more limited access to extension. The impact of varying
access to extension services will be estimated for each treatment by including a loss
discount factor. 4

This analysis assumes that ”traditional” and "advanced" farmers using a traditional
storage method (the farmer’s control) do not require extension service support to
achieve current storage loss levels--i.e., loss levels based on analysis of gain samples
collected by Wolfson (1990). However, in evaluating the new storage technology, the
analysis assumes that ”traditional” farmers will obtain only 90% of the goss benefit of
the technology and the "advanced” farmer will obtain 100% of the potential benefit.28
Madam

Farmer characteristics that may influence the adoption of the proposed
new/ improved cowpea gain storage technologies include tastes and preferences, farm
size, labor availability, farm income and household size.
Tastes an Preferences

Farmers generally prefer undamaged COWpeas (without holes) because of the

possible loss in germinative value. Consumers generally prefer undamaged coneas

 

2"Advanced adopter farmers tend to gow cotton and are likely to have good
extension service (i.e., SODECOTON).

 

 

92
because of the nutritive loss and the “WW flavor resulting from the presence of

larvae (Murdock, personal interview).

In analyzing the new storage technologies, the market price of the damaged
cowpea will be discounted to account for taste preferences for undamaged gain.
Although little empirical data exist, antidotal evidence indicate that a premium is paid
for undamaged gains. Therefore, undamaged cowpeas will be valued at a 20% higher
price than damaged COWpeaS.

Pam Size

The majority of cowpea producers in the northern Cameroon gow COWpeas
primarily for home consumption, planting on average one hectare (regardless of cr0pping
system) and harvesting 134 kg. Yet since area planted and total production vary between
farmer types, these variables are adjusted in the analysis to reflect the total production
(i.e., initial quantity placed in on-farm storage) harvested by "traditional” and ”advanced”
farmers.

Labor Availability

New technologies often increase labor requirements. Farmers may obtain labor
by hiring it or by using family labor. If family labor is not available and farmers have
cash, they typically hire labor. But, because labor requirements vary little between the
new cOWpea storage technologies and household labor is assumed to be available, no
opportunity cost is assigned to the labor input.

Hpusehold Size

By reducing pest losses, the improved storage technology allows households to

increase their ”supply” of COWpeas. For cowpea deficit households (i.e., available supply

is depleted before the next harvest), the new technology allows them to extend their

93

cowpea supply for one or more months. For surplus households, it allows them to sell a
larger quantity at the high end-of-season-price. But, assuming that households consume
cowpeas (i.e., draw down their stocks) over the storage season, the value of these

benefits will vary, depending on the rate of utilization. This analysis assumes household

consume 1.6 kgs per capita per month.

4.6 Summary

This analysis generates both the average and marginal rates of return to COWpea

 

gain storage technologies developed and/or promoted by the IRA/CRSP project in

northern Cameroon. Differences between farmer ”types” with respect to management

 

practices, capacity to bear risk, access to credit and extension services, and access to both
input and output markets are considered in the analysis.

Factors which will affect the adoption of the new/ improved storage technologies
by northern Cameroonian cowpea farmers include both factors associated to the
innovation’s relative advantage (i.e., the profitability of the innovation, its characteristics,
ago-chatic conditions, the institutional support available to sustain farmer adoption)
and the characteristics of the farmers (i.e., human capital, farm size, labor availability,
farm income, household size). This analysis incorporates these socioeconomic factors to
assess, ex ante, the likely profitability of the proposed storage technologies to both

"advanced” and ”traditional" farmers.

 

2"This analysis assesses the profitability of the various storage technologies under
both ”advanced” and "traditional” farmers’ storage situation.

CHAPTER 5 RATE OF RETURN ANALYSIS OF ALTERNATIVE

GRAIN STORAGE TECHNOLOGIES

This chapter is divided into three sections. The first section specifies the cost
and benefit streams associated with the technologies evaluated. It describes the
components which comprise each stream; the underlaying data, their sources and their
limitations; and the assumptions made in interpreting these data. The second section
applies average and marginal rate of return analysis to the improved storage technologies
under ”advanced" and "traditional” farmers’ utilization for coneas intended for home
consumption and/ or speculation (sale). It also applies sensitivity analysis to examine the
effects of modifying critical parameter values. The final section applies an expected
revenue analysis to determine the profitability to an ”advanced" farmer investing in either

the improved ash storage technology for speculation.

5.1 General Approach

The cost streams represent estimates of material costs and depreciation for the
various cowpea gain storage methods. The benefit streams estimate the dollar value of
COWpea gain ”saved”--calculated as beginning stocks minus consumption, minus loss due
to insects, using the traditional and improved cowpea storage technologies.
5.1.1 Storage Technology Cost Stream

to a co nolo -- nves ent Cost
The first decision a farmer must make is whether to sell his/her crop at harvest

or store it in anticipation of a higher future return. Once the farmer has decided to

94

95

store, he/ she must decide which storage method to use. The five alternative storage

methods require farmers to invest from 0 to 7,400 CFA (Table 5.1).

Table -5.1 Initial Investment Cost of Various Storage Technologies.

Storage Structure Container Volume Cost / unit‘
(kg) (CFA)

 

Cannary 50 1,500

 

Granary na
Plastic Bag 50
Sack 50

 

 

 

 

 

 

 

Solar Heater

‘US $1 = 250 CFA.

l’Although these technologies may have some salvage value, the analyses assumes a
zero salvage value.

”The cost of the solar heater is shared evenly among 10 households.

Source: Various CRSP Bulletins and key informants.

Interest Pa ents ortuni Cost of Ca ita

Since formal credit institutions are not available in rural northern Cameroon,
cowpea farmers must obtain credit from money lenders, or purchase new technology
from their savings. Economic analysis requires that own capital (savings) be valued at its
opportunity cost. The base run values capital at 3% per month. This opportunity cost of
capital is set at the interest rate that farmers would have to pay if they borrowed from
money lenders or informal credit institutions.
Qppprtppity Cost of Stoggd 61am

A farmer can either sell his/her cowpea gain at harvest or store it anticipating a

higher future price. Yet foregoing the opportunity to sell the gain at harvest may

96

require the low-income farmer to borrow money to cover outstanding debts and
immediate household needs. Thus, to evaluate a farmer’s ”sell at harvest or store"
decision, an opportunity cost for the stored gain must be assigned to reflect this
foregone cash. The stored gain’s opportunity cost is calculated as the farmgate price”,
less the cost of transporting the gain to the market, multiplied by an interest rate (a
discount rate)". On the other hand, in evaluating the four storage options (marginal
analysis) no opportunity cost is assigned to the stored gain because marginal rate of
return analysis requires that only costs that vary between treatments be included in the
analysis.
Transportation Cost

Currently, the plastic bags and sheets are only available in the Maroua market
and earthenware cannaries and cloth sacks are typically purchases in the Maroua market.
To purchase these inputs, farmers would have to pay an average (two way)
transportation cost of 500 CFA. But, because this cost does not very across treatments
(i.e., one trip would be required to purchase the inputs required for each of the
alternative technologies), a transportation cost is not included in the marginal rate of
return analysis.

Similarly, no transport cost is included for delivering cowpeas to urban markets,

since cost data are not available.

 

z’“Since farmgate price data and transport cost are not available, the analysis assumes
that the market price equals the farmgate price. This may slightly increase the
profitability of the new technology.

31This analysis uses a 3% per month interest rate.

 

 

97

reci '0
An asset with a useful life of geater than 1 year must be amortized over the life
of the asset to estimate its annual use cost. Since each technology has a different useful

life (Table 5.1), its annual cost is estimated using the formula for calculating straight-line

depreciation:
D = (C's) (5.1)
Y
where:
D = depreciation per year by straight-line method
C = purchase cost
S = salvage value at end of usage period
Y = expected years of usage

5.1.2 Storage Technology Benefit Stream
Begip' rim g Stock

A household’s beginning cowpea stock is equal to last year’s carry-over plus the
current year’s harvest. Since most northern Cameroonian households do not produce
sufficient COWpeas to last through the year, beginning stocks are assumed to be equal to
the current season’s total production.

Dry cowpea pods are generally harvested over a three-month period, beginning in
late September and continuing through November. This analysis assumes thatthe
average farmer harvests, drys, and threshes harvested cOWpeas during late September
through October, and the crop is put into the store on November 1.

Copr stock levels are dynamic, constantly changing over time, as a result of
draw-down--due to household consumption, market sales, and storage losses. The

analysis incorporates this utilization pattern to compute beginning stocks on a monthly

98

basis--each previous month’s ending stock becomes the following month’s beginning
stock.
Consumptipn

The first component of stock draw-down is total household consumption, which is
a function of family size, composition, and the amount eaten per person per meal. Table
5.2 presents the estimated consumption schedule for the traditional and advanced
farmers. At current production levels, households produce only enough COWpeas to meet

family needs for 4—6 months.

Table 5.2 Estimated Cowpea Consumption Schedule and Months of Self-Sufficiency for
Two Farmer Categories, Northern Cameroon.

Household Household Beginning Consumption
Classification Size Stocks (kg) / Month (kg)‘

  

 

   
 
 

 

E

Traditional 10 82 16

I Advanced 19 287 30.4
&

'Estimate based on average consumption of 1.6 kg per person per month.
t’Months the available stock will last, assuming observed storage losses and zero
sales at harvest, as discussed below.

Source: Analysis of data collected by Wolfson (1990).

 

 

 

 

 

 

 

 

 

Stora e sses

The second component of stock draw-down is storage losses, which are
determined by the method of storage practiced. Since storage losses represent a cost to
the household, investments in technologies that reduce storage losses may be a profitable

investment for some households.

99

Ideally, monthly storage losses associated with each alternative technology should
be estimated by monthly sampling of gain stored under each of the storage methods.
Since gain samples were only taken once (March, 1990), storage losses over time are
estimated using a logistic function”, where P(t) equals the percentage of storage loss at

the time of sampling33 (Figure 5.1).

 

P: = K (5.2)
1+be "
where:
P(t) = average total storage loss, in period t

loss ceiling, 100% of stock destroyed
a parameter of the function
time period, life-cycle per generation

‘77:
u II II

t
Recognizing that storage losses occur throughout the month, average monthly stocks are
estimated, based on the mean of beginning and ending stocks.

Sales

 

The third component of stock draw-down is cowpea gain sales. Since no
household level data is available to estimate the volume of cowpea gain sales, the
marginal analysis assumes 0% sales at harvest. Subsequent analysis of the farmers’ "sell
verses store” decision assumes sales at month 10 (August) when the price for cOWpea

gain peaks (section 5.3).

 

32Dr. Richard Shade suggested that a logistic function is an appropriate functional
form for modeling bruchid population dynamics over time.

33Estimates of farmers’ storage losses using traditional technology are based on gain
samples collected from farmers in March 1990, approximately four months after harvest.
Estimates of losses associated with the new storage technology are based on
experimental storage trials, sampled after three months in storage.

100
W

Cowpea market prices increase from a seasonal low at harvest to a seasonal high
preceding the next harvest. If cowpeas are sold, they must be valued at the price
households would receive in the month of the sale. But farmers who do not sell cowpeas
still benefit from the technology, since reduced storage losses will extend their period of
self-sufficiency. For these households, the gain ”saved” (as a result of less losses) is
valued at the price the household would have to pay to purchase cowpeas in the market
at the prevailing market price, if they had not used the storage technology which
provided additional months of self-sufficiency.

In 1989 and 1990 the TLU conducted market surveys and reported average
monthly prices across six rural markets in the Far North Province“. These monthly
cowpea market price data are used to value ”saved” gain. Average prices, based on two
years of price data (1989-90), ranged from a low of 101 CFA/ kg in December to a high
of 196 CFA/kg in August (Figure 5.2).

These data indicate that the market price varies both between years and over the
year. The base run uses an average price across the two markets. A range of prices are
later tested during sensitivity analysis to evaluate the impact of cowpea gain prices on

the profitability of adoption.

 

3‘Monthly market prices were collected in six districts of Mayo-Sava and Mayo-
Tsanaga Departments.

101

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100.00
Storage Losses Expereincad by: , ’5
90.00 7’ r
/
"Advanced" Farmers T, r‘//
/ I
80.00 r ,
"Moderate" Farmers—[J—j’/
70.00 ,’ ,’
"Trodltlonol" Farmers—,’ ,’/
l l
8 50.00 I I
g I, I, Storage Losses
.. 50.00 I’ I!
g I I Using:
3 z I
“- 40.00 r I
I I
I z / Improved Ash
30.00 ,’ ,’
l I °
9.9a» Haves? , , / Triple 9T9
20.00 ,1 I’
Put In Sloro / / Solcr Hooter 40h Triplq Bag
1 - ’ . I
10.00 r i I
,c.’ _________ l__l .......
’ 3'0 "
0.00 I r ‘ I _ ‘ T— - r I I l I I T I
Sept Oct Nov Dec Jan Pd Mach April May June July Am
“on":

Figure 5.1. Insect Population Growth, On-Farm Trials and Farmers’ Samples,
Cameroon.

Note: Monthly storage losses are estimated using a log function, in which farmers’ losses
are based on 4 months of farmer storage and estimates of storage losses under the
improved technology are based on 3 months of storage.

102

 

 

 

 

 

  

 

 

 

   

 

   

 

 

260
2w 3“
I \
I \
I \
220 I, \\
Koala makai /’ ‘1
1 989 ~90 ’ ‘
zoo ' ‘
I i
.x
D 180
9.—
8 Average
150 ~._--1 9 89 -90
Morouo market .
14o 1989-\90
120
100

 

 

 

I I I I I I I I
Jan Feb hitch April May in My Aug
Months

Figure 5.2. Seasonal Cowpea Prices, Far North Province, Cameroon, 1989-1990.

103

W

Gross benefits to each new cOWpea storage technology are estimated by
subtracting the storage losses incurred using the new storage technology from the losses
incurred under the households’ current storage practice to calculate the losses avoided
(gain saved) using the new storage technology. The "gain saved" (kg) is then multiplied
by the market price in the month in which the household’s store is depleted, since in the
absence of the new technology the household would have to go to the market to replace

the cowpea gain ”lost" to storage insect pests.

5.2 Farmers’ Utilization of On-Farm Storage

On-farm storage bridges the time lag between production and ultimate use,
allowing households to postpone allocative decisions. From the farmers’ perspective, by
reducing losses, improved on-farm storage technology allows households to: 1) improve
their food security by extending their food availability; and 2) provides geater
opportunity for speculation (i.e., the ability earn profits by storing and selling when the
price is at its peak).

Households’ gain-storing decisions are influenced by technical and social factors,
including differences in income, production and their consumption patterns. For
example, improved storage may allow low-income (and low cowpea production)
households to store gain and thereby increase their security in consumption, but the
relatively small amount that they produce preclude their storing for speculation. On the
other hand, a high-income (and high cowpea production) household may produce
sufficient cowpeas to satisfy consumption needs and still have available enough surplus

gain for speculation.

104

As noted earlier, the stock of cOWpea gain a farmer has available throughout the
storage period is a function of the household’s total production (i.e., initial inventory),
rate of storage losses, and the rate at which it draws down its stocks. As the household
draws down its cowpea inventory, the increasing level of damage caused by storage pests
impacts on a decreasing volume of stored gain. Hence, although experiments show high
levels of bruchid damage (percent of damaged gain) after several months of storage,
these high loss levels actually will only affect farmers who initially placed large gain
surpluses in storage. For example, ”traditional” farmers with initial cowpea inventories of
only 82 kg/household will consume their supply of COWpeas after only four months.
Consequently, they have little to gain from adopting improved storage technologies
because during the early storage period (months 1-4) bruchid populations remain low.
And by the time bruchid damage is potentially severe, these households have depleted
their COWpea inventories.

In contrast, ”advanced” farmers with initial cowpea inventories of 287
kg/household store sufficient gain to meet household consumption requirements for six
months. Thus, these farmers have the most to gain from adopting the improved storage
technologies because they still hold substantial inventories during months 5-6 when
bruchid populations are high and the potential for severe loss is geat.

The following analysis uses benefit-cost analysis to test the hypotheses discussed
above by evaluating the economic returns (average and marginal) to adopting the

improved storage technology, for both ”traditional” and "advanced” farmers”.

 

3”This analysis focuses on ”traditional” and ”advanced” farmers because they represent
highly contrasting cases. “Traditional" farmers typical of the region, account for 47% of
the sample. On the other hand, the analysis of the profitability of new storage
technology for ”advanced” farmers indieates its potential if new varieties lead to higher
yields.

105

5.2.1 Traditional Farmer Situation

Approximately 47 percent of the survey farmers were classified as “traditional”
farmers. These households, categorized as non-adopters of improved production
practices, annually harvest an average of 82 kg of cowpea gain and tend to store their

cowpea gain in traditional ganaries. These households average 10 members, and

 

consume 16 kg/month of cowpea (Table 5.2).
5.2.1.1 Storage for Home Consumption: Base Run

Assuming all of their harvest is stored for home consumption using traditional

 

storage technologies, their inventories will be sufficient to allow the household to meet
their consumption requirements for 4 months (November through February) before
having to purchase additional cowpeas in the market“. By investing in any of the
improved cOWpea storage technologies developed by CRSP/IRA researchers, the
household could extend their period of self-sufficiency. But because ”traditional” farmers
tend to have less access to extension services and may not use the improved storage
technologies correctly, the following analysis assume they capture only 90% of the
protection potential of these improved storage technologies.

To assess the likelihood that ”traditional” farmers would find these new
technologies economically viable (profitable), the average and marginal rates of return to
investing in each of the improved cowpea storage technologies were estimated (Table
5.3).

In summary, the base run shows that if a "traditional” farmer values his/her own

or borrowed funds at a monthly interest rate of 3% (base run), all of the improved gain

 

“Based on logistic function estimating weevil population gowth under advanced
adopter storage conditions.

106

storage technologies are uneconomical. For all three improved technologies, the value of
the ”gain saved” is less than the cost of investing in the new technology-resulting in a
negative average rate of return to all of these investments. Furthermore, because none
of these technologies give positive average rates of return, it is not necessary to estimate
their marginal rate of return--all are dominated by (inferior to) the "traditional” farmer’s
existing storage technology. Farmers will not earn positive profits because the cowpea
gain ”saved” by adopting these improved storage technologies ranges from only 4.4 to
6.1 kg of gain, depending on the new technology considered. The level of ”saved" gain
is so low because ”traditional” farmers incur minimal gain losses during the first 4
months in storage, while the large potential benefits from improved gain storage
technologies do not materialize until later in the storage season-dong after these farmers
have exhausted their inventories.
5.2.1.2 Storage for Home Consumption: Sensitivity Analysis

To evaluate the sensitivity of these results, with respect to values assigned to the
five key parameters”, each of these values were set at + /- 25 to 50% of their assumed
base run values. Recalculation of the average and marginal rates of return showed that
only when household storage losses were increased by 50%, did the improved ash and
triple bag technology have a positive rate of return of 30 and 5.1%, respectively. For
every other run in the sensitivity analysis, the improved gain storage technologies
remained dominated by the “traditional” farmers’ existing storage method (Tables 5.4 -

5.6).

 

3"The five parameters varied in the sensitivity analysis are the households’ current
level of gain losses using his/her traditional storage method, gain losses associated with
the improved storage technologies, cost of the technology, market price of COWpea gain,
and the opportunity cost of capital.

107

Table 5.3 Base Run for ”Traditional" Farmers: Partial Budget and Rate of Returns
Analysis of Improved Cowpea Storage Technologies for Grain Intended for
Home Consumption‘.

 

 

 

 

 

 

Farmers’ Improved Triple Solar Heater
Current Ash Bag & Triple Bag
Practice” Storagec Storage‘ Storage‘
Grain Saved (kgs) 0 4.4 6.1 6.1
Partial Budget (CFA)
Gross Benefits' 0 497 689 689
Total Costs‘ 0 3,478 1,043 1,901
Annual Costs|| 0 696 1,043 1,472
Net Benefits NA -199 -354 -783
(gross benefits minus
annual cost)
Marginal Benefits and
Costs (CFA)
Additional Net Benefits NA -199 -155 -429
Additional Annual Costs NA 696 647 429
Rate of Returns (%)
Average NA -29 -34 -53
Marginal NA D D D
'82 kg of coma gain put into storage.
I’Granary.
’2 cannaries.
‘6 plastic bags.

‘1 solar heater shared by 10 households plus 6 plastic bags.

'COWpea gain (kg) ”saved" valued at month 5 (March) market price of 113 CFA/kg.
‘Includes Opportunity cost of capital (3% per month) for 5 months (Nov. - March).
'Total costs/ useful life of technology.

NA=not applicable; D = dominated.

108

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11 1
5.2.2 Advanced Farmer Situation

Approximately 22 percent of the survey farmers were classified as ”advanced”
farmers. These households adopted the improved production technology package,
annually harvested 287 kg of cowpea grain and tended to store their grain in cloth sacks.
These households average 19 members and consumed 30.4 kg/ month of COWpeas (Table
5.2).
5.2.2.1 Storage for Home Consumption: Base Run

Assuming all of their harvest is stored for home consumption using "advanced"
farmers’ storage technology, their inventories would be sufficient to allow the household
to meet their consumption requirements for approximately 6.5 months (November
through mid-May) before having to purchase additional COWpeas in the market. By
investing in the improved COWpea storage technology, the household could extend their
period of self-sufficiency.

Because ”advanced" farmers tend to have good access to extension services, the
following analysis assumes they will use the improved storage technologies correctly and
receive all (100%) potential benefits.

When an "advanced” farmer uses the improved storage technologies, he/she will
be able to extend their period of self-sufficiency approximately two more months (mid-
May through mid-July) (Table 5.7).

To assess the likelihood that "advanced” farmers would find these new
technologies economically viable (profitable), the average and marginal rate of return to
investing in each of the improved COWpea storage technologies were calculated (Table

5.7).

112

These results show that when an “advanced” farmer values his/ her own funds or
borrows the funds at a monthly interest rate of 3% (base run), adopting the improved
ash, triple bag, and solar heater with triple bag storage technology implies a 177, 116,
and 90% average rate of return (ARR), respectively to grain stored for home
consumption. These results suggest that adopting any one of the alternative

improved/new grain storage technologies would by economically attractive for the

 

”advanced” farmer, since all exceed the 50% minimum rate of return proposed by
CIMMYT (1988).

Marginal returns analysis provides a technique for looking more critically at the

 

"advanced” farmers’ choice of technology decision. Table 5.7 presents data for the
alternative improved technologies, arranged from the least costly (improved ash) to the
most expensive (solar heater with triple bag). Compared to the farmers’ current storage
technology, improved ash gives a marginal ROR of 265% In other words, by investing
an additional 1,476 CFA in ash storage, benefits are increased to 3,917 CFA. Thus, the
marginal ROR (3,917 divided by 1,467) equals 265%-suggesting a very attractive
investment option.

In order to adopt triple bagging, the farmer would have to invest an additional
1,107 CFA (above the cost of the ash technology) but, he/she would earn -66 CFA less
profit (net benefits) from investing in the triple bag technology-compared to ash storage.
Similarly, although the solar heater with triple bag technology has a positive (90%) ARR,
it generates a lower net benefit (—455 CFA)--compared to the triple bag technology.

In summary, the base run analysis shows that for an "advanced" farmer storing

his/her total crop for home consumption, all three improved technologies give attractive

113
ARRs. But, the MRR analysis clearly shows that if a farmer could adopt improved ash

storage, it would be irrational for him/her to invest in either the triple bag or solar
heater with triple bag technology-since they are all dominated by improved ash storage.
These results are largely driven by the storage loss data used in the analysis. Available
experimental data (Table 3.5) show thatnin terms of potential pest loss reduction--the
triple bag technology is only slightly more effective than improved ash storage.
Furthermore, the triple bag technology and solar heater with triple bagging are
equivalent--in terms of loss reduction-«but the later is more costly to adopt.
5.2.2.2 Storage for Home Consumption: Sensitivity Analysis

Although the base run represents the "best estimate" of the average and marginal
returns to cowpea grain storage technologies, sensitivity analysis is conducted to test the
variability in rate of return, associated with alternative assumptions regarding the data
values used in these analyses. Further, given that some data used in the analysis are
based on "informed assumptions” rather than empirical findings, sensitivity analysis
indicated the degree to which each assumption affects the results.

Five parameters38 were identified as having a significant influence on the rates
of return for the improved grain storage technologies (Tables 5.8 - 5.10). Six sensitivity
analyses are presented below. Each analysis assesses the impact of altering one of the
five ”critical parameters” on the rate of return to investing in the three new technologies-

-improved ash storage, triple bagging storage, and solar heater with triple bag storage.

 

1"“'I'he five parameters varied in the sensitivity analysis are the households’ current
level of grain losses using his/her traditional storage method, the losses associated with
using the improved technologies, technology cost, market price of cowpea grain, and the
opportunity cost of capital.

 

 

114

Table 5.7 Base Run for ”Advanced” Farmers: Partial Budget and Rate of Returns
Analysis of Improved Cowpea Storage Technologies for Grain Intended for
Home Consumption‘.

 

Farmers’ Improved Triple

Current Ash Bag
Practiceb Storage‘ Storage‘I

  

' Grain Saved (kgs) o 52.4 61.3 61.3

 

 

Partial Budget (CFA)

Gross Benefits' 0 6,131 7,172 7,172
I

Total Costs' 2,214 11,069 3,321 4,231

Annual Costs“ 738 2,214 3,321 3,776

Net Benefits NA 3,917 3,851 3,396

(gross benefits minus

annual costs)

Marginal Benefits and

Costs (CFA)

Additional Net Benefits NA 3,917 -66 -455
Additional Annual Costs NA 1,476 1,107 455
Rate of Returns (%)

Average NA 177 116 90

Marginal NA 265 D D
m
‘287 kg of coma grain put into storage.

.’6 cloth sacks.

c6 cannaries.

‘18 plastic bags.

‘1 solar heater shared by 10 households plus 18 plastic bags.

‘Cowpea grain (kg) "saved” valued at month 7 (May) market price of 117 CFA.
‘Includcs opportunity cost of capital (3% per month) for 7 months (November - May).
“Total costs/ useful life of technology.

NA = not applicable; D = dominated.

 

 

115

 

 

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118

Ru 1: a ers’ Cu ent e 0 St

In the base run analysis, annual storage losses were estimated using a logistic
function (Equation 5.1), based on farm-level storage loss data collected in March 1990.
By testing the robustness of these estimates, sensitivity analysis determines to what
degree the rate of return estimate depends on the accuracy of these data.
Improved Ash Storage

In the base run analysis, by adopting improved ash storage ”advanced" farmers
gained an additional 52.4 kg of COWpea grain; and earned a 177 percent ARR and a 265
percent MRR on their investment (Table 5.7). When the assumed level of the
”advanced” farmers’ current storage losses is increased by 50%, (10.5% of the stock lost
by the end of the fourth month in storage39 vs. 7% in the base run), the additional grain
available increases to 69.7 kg; and the ARR and MRR increase to 368 and 403 percent,
respectively. This is because when the assumed level of farmers’ losses is increased by
50%, the household runs out of 00me approximately 2 weeks sooner. By adopting
improved ash storage, the household saves 69.7 kg (vs. 52.4 kg in the base run). These
”saved” cowpeas are valued at the May market price of 117 CFA/kg, since this is the
price the household would have had to pay to purchase cowpeas in the market in May--if
they had not adopted ash storage.

In contrast, when the assumed level of the "advanced” farmers losses is decreased
by 50% (3.5% of the stock lost by the fourth month in storage vs. 7% in the base run),
adopting ash storage reduces the amount of grain saved to 44.8 kg, and the ARR and

MRR to ash storage increase to 239 and 354 percent, respectively. Intuitively, one would

 

3“Survey data showed that losses averaged 7% by the end of four months in storage.
In this analysis, this loss parameter was increased / decreased 50% and the new value was
used in the logistic curve to estimate total losses.

119

expect that the returns to improved grain storage technologies should decrease when the
level of protection under the farmers’ current storage method increases. This observed
counter intuitive increase in returns to adopting ash storage occurs for the following
reason. If farmers’ losses are 50% less using their current technology, they are able to
meet consumption requirements from their own stocks for 7 months and two weeks
(compared to 6.5 months in the base run)--lessening the benefits of improved storage
technologies. But, the additional grain saved (44.8 kg) by adopting improved ash storage
under this situation is valued at the June market price of 171 CFA/kg, since this is the
price the household would have had to pay to purchase cowpeas in the market in June.
Consequently, the net benefit to adopting the improved ash storage technology increases
because of the rise in the market price of COWpea grain (from 117 CFA/ kg in May to
171 CFA/kg in June).
Triple Bag Storage

In the base run, by adopting triple bag storage "advanced” framers gained an
additional 61.3 kg and; earned a 116 percent ARR, but the MRR was dominated by
improved ash storage (i.e., the return to the additional capital required to invest in triple
bag storage was less than the additional cost of this investment”) (Table 5.7). When the
assumed level of the ”advanced” farmers’ current storage losses is increased by 50%, the
ARR increases 61 percentage points to 177, but the MRR remains dominated. The
ARR increases because when assumed farmers’ losses were increased by 50%, the
household runs out of cOWpeas sooner in May, when the market cowpea price is 117
CFA/kg. Now adoption of triple bagging "saves" 78.7 kg (vs. 61.3 kg in the base run) of

cowpeas, which is valued at 117 CFA/kg. But, the MRR is still dominated because the

 

 

120

benefits (i.e., reduced losses) of the triple bag storage are not sufficient to cover the
additional costs of the triple bag technology.

In contrast, when the assumed level of ”advanced” farmers’ losses is decreased by
50%, the additional grain made available by adopting triple bagging decreases to 53.8 kg;
and the ARR to triple bagging increases by 53 percentage points to 169 percent and the
MRR increases to 35%. The household under the current storage method now runs out
of cowpeas in June, when the market price is 171 CFA/kg. Even though the amount of
cowpea grain "saved" decreases to 53.8 kg, the ”saved" grain is valued at a higher price--
causing the ARR and MRR to increase.
Solar Heater with Triple Bag Storage

In the base run, by adopting the solar heater with triple bagging storage
"advanced” farmers gained an additional 61.3 kg”; and earned a 90% ARR, but the
MRR was dominated by ash storage (Table 5.7). When the assumed level of the
"advanced” farmers’ current storage loss estimate is increased by 50%, the ARR
increases 54 percentage points to 144 percent. The ARR increases because when the
assumed level of farmers’ losses is increased by 50%, the household runs out of COWpeas
sooner in May, when the market cowpea price is 117 CFA/kg. Now, adoption of the
solar heater with triple bagging ”saves" 78.7 kg (vs. 61.3 kg in the base run) of cOWpeas,
which is valued at 117 CFA/kg. But, the MRR is still dominated because the benefits
(i.e., reduced losses) of the solar heater with triple bag storage are not sufficient to cover

the additional costs of the solar heater with triple bag technology.

 

”The experimental results showed that triple bagging and the solar heater with triple
bagging were equally effective in reducing storage losses.

 

 

121

In contrast, when the assumed level of "advanced” farmers’ losses are decreased
by 50%, the ARR to solar heater with triple bagging increases by 47 percentage points to
137 percent and the MRR remains dominated. The household now runs out of cowpeas
in June, when the market price is 171 CFA/kg. Even though the amount of cowpea
grain ”saved“ decreases to 53.8 kg, the ”saved“ grain is valued at a higher price--causing
the ARR to increase.

u ° ovedStrae ecnlo t 'o

In the base run analysis, the level of protection data were based on on-farm
demonstrations of the improved storage technologies. Because so few trials were
conducted, the sensitivity of the returns in the base run is tested by assuming various
levels of protection provided by the three improved technologies.

Improved Ash Storage

When the assumed level of loss using improved ash storage is increased (i.e., less
effective) by 50% (9% of the stock lost by the third month in storage vs. 6% in the base
run), the ARR decreases by 20 percentage points to 157 percent and the MRR decreases
by 30 percentage points to 235 percent. This observed decrease in returns to adopting
ash storage occurs because assuming 50% more "losses" under the improved ash
technology results in less grain "saved" (48.6 kg), which is valued at the May market price
of 117 CFA/ kg. Since the traditional storage practice (cloth sacks) is being replaced by
the improved ash storage, an increase in the value of this parameter will result in a lower
rate of return. By setting a lower protection level for the improved ash storage
technology, the improved ash storage technology will certainly appear less profitable than

in the base run.

 

 

122

When the assumed level of loss using the improved ash storage is decreased (i.e.,
more effective) by 50% (3% of the stock lost by the third month in storage vs. 6 % in
the base run), the ARR increases by 19 percentage points to 196 percent, and the MRR
increases by 29 percentage points to 294 percent. Setting a higher protection level for
the improved ash storage technology, results in more grain "saved” (56.04 kg), which is
valued at the May market price of 117 CFA/kg.

Triple Bag Storage

When the assumed level of loss using triple bag storage is increased (i.e., less
effective) by 50% (4.5% of the stock lost by the third month in storage vs. 3% in the
base run), the ARR decreases by 42 percentage points to 74 percent and the MRR
remains dominated. Setting a 50% lower protection level for triple bagging, results in
less grain ”saved” (49.5 kg), and in turn a lower rate of return.

When the assumed level of loss using triple bag storage is decreased (i.e., more
effective) by 50% (1.5% of the stock lost by the third month in storage vs. 3% in the
base run), the ARR increases by 7 percentage points to 123 percent and the MRR
remains dominated. Setting a 50% higher protection level for triple bagging, results in
more grain "saved” (63.2 kg), and in turn a higher rate of return.

Solar Heater with Triple Bag Storage

When the assumed level of loss using the solar heater with triple bag storage is
increased (i.e., less effective) by 50% (4.5% of the stock lost by the third month in
storage vs. 3% in the base run), the ARR decreases by 37 percentage points to 53
percent and the MRR remains dominated. Setting a 50% lower protection level for the
solar heater with triple bagging technology, results in less grain "saved" (49.5 kg), and in

turn a lower rate of return.

 

123

When the assumed level of loss using the solar heater with triple bag storage is
decreased (i.e., more effective) by 50% (1.5% of the stock lost by the third month in
storage vs. 3% in the base run), the ARR increases by 6 percentage points to 96 percent
and the MRR remains dominated. Setting a 50% higher protection level for the solar
heater with triple bagging technology, results in more gain "saved” (63.2 kg), and in turn
a higher rate of return.

it : roved Sto a e cc 3

In the base run analysis, although most cost figures of the improved storage
technology were directly quoted from CRSP documents, there is still a possibility that
variable costs were over/ under estimated. Thus, the cost variable is varied to estimate
how sensitive the returns to improved gain storage technologies are to higher/lower
total input costs.

Improved Ash Storage

When total input costs of the improved ash storage technology are increased by
25%, the ARR decreases by 55 percentage points to 122 percent and the MRR
decreases by 83 percentage points to 182 percent. This observed decrease in the rates of
return to improved ash are expected because although the benefits (52.4 kg of gain
”saved”) have not changed, the cost of adopting the improved ash storage technology is
now 25% higher.

When total input costs of the improved ash storage technology are decreased by
25%, the ARR increases by 92 percentage points to 269 percent and the MRR increases
by 139 percentage points to 404 percent. This observed increase in the rates of return to

improved ash is again expected because although the benefits (52.4 kg of gain ”saved”)

 

124

have not changed, the cost of adopting the improved ash storage technology is now 25%
lower.
Triple Bag Storage

When total input costs of the triple bag storage technology are increased by 25 %,
the ARR decreases by 43 percentage points to 73 percent and the MRR remains
dominated. This observed decrease in the ARR to triple bagging is expected because
although the benefits (61.3 kg of gain 'saved') have not changed, the cost of adopting
the triple bag storage technology is now 25% higher.

When total input costs of the triple bag storage technology is decreased by 25%,
the ARR increases by 72 percentage points to 188 percent and the MRR increases by 25
percentage points to 25 percent. This observed increase in the ARR to triple bagging is
again expected because although the benefits (61.3 kg of gain 'saved”) have not changed,
the cost of adopting the triple bag storage technology is now 25% lower. The MRR
increases because the return to the additional capital required to invest in triple bag
storage is now geater than the additional cost of this investment.
Solar Heater with Triple Bag Storage

When total input costs of the solar heater with triple bag storage technology are
increased by 25%, the ARR decreases by 63 percentage points to -27 percent and the
MRR remains dominated. The ARR to the solar heater with triple bagging becomes
negative because although the benefits (61.3 kg of gain ”saved”) have not changed, the
cost of adopting the solar heater with triple bag storage technology is now 25% higher.

When total input costs of the solar heater with triple bag storage technology is
decreased by 25%, the ARR increases by 63 percentage points to 153 percent and the

MRR remains dominated. This observed increase in the ARR is again expected because

125
although the benefits (61.3 kg of grain 'saved") have not changed, the cost of adopting

the triple bag storage technology is now 25 % lower.
Rug 4: Market Brice of Cowpea

In the base run analysis, the market price for cowpea gain was based on two
years of price data (1989-1990) collected by the TLU. Because market prices vary across
years and across markets, the gain price is varied to estimate how sensitive the returns
to improved gain storage technologies are to price.

Improved Ash Storage

When the market price for COWpea gain is increased by 25% (from 117 to 146.25
CFA/kg), the ARR increases by 69 percentage points to 246 percent and the MRR
increases by 104 percentage points to 369 percent. This observed increase in the rates of
return to improved ash is expected because the value of the benefits (52.4 kg of gain
”saved") has increased, but the cost of adopting the improved ash storage technology has
not changed.

When the market price for COWpea gain is decreased by 25% (from 117 to 87.75
CFA/kg), the ARR decreases by 69 percentage points to 108 percent and the MRR
decreases by 103 percentage points to 162 percent. This observed decrease in the rates
of return to improved ash is again expected because the value of the benefits (52.4 kg of
gain "saved") has decreased, but the cost of adopting the improved ash storage
technology has not changed.

Triple Bag Storage

When the market price for cowpea gain is increased by 25%, the ARR increases

by 54 percentage points to 170 percent and the MRR increases by 18 percentage points

to 18 percent. This observed increase in the rates of return to triple bagging is expected

126
because the value of the benefits (613 kg of gain 'saved") have increased, but the cost

of adopting the triple bag storage technology has not changed.

When the market price for cOWpea gain is decreased by 25 %, the ARR
decreases by 54 percentage points to 62 percent and the MRR remains dominated. This
observed decrease in the rates of return to triple bagging is again expected because the
value of the benefits (61.3 kg of gain 'saved") have increased, but the cost of adopting
the triple bagging storage technology has not changed.

Solar Heater with Triple Bag Storage

When the market price for cowpea gain is increased by 25%, the ARR increases
by 47 percentage points to 137 percent and the MRR remains dominated. 'Ihis observed
increase in the rate of return to the solar heater with triple bagging is expected because
the value of the benefits (61.3 kg of gain ”saved”) has increased, but the cost of adopting
the solar heater with triple bag storage technology has not changed.

When the market price for cowpea gain is decreased by 25%, the ARR
decreases by 52 percentage points to 42 percent and the MRR remains dominated. This
observed decrease in the rate of return to the solar heater with triple bagging is again
expected because the value of the benefits (61.3 kg of gain "saved") has increased, but
the cost of adopting the solar heater with triple bagging storage technology has not
changed.

u 5: Interest Rate ortuni Cost of Ca ital

In the base run analysis, the opportunity cost of capital is set at a 3 percent per

month interest rate, representing the interest rate that farmers would have to pay if they

borrowed from money lenders or informal credit institutions. The opportunity cost of

127

capital represents an additional cost to the farmer of adopting any of the improved
storage technologies and thus affects the returns to the improved technologies.
Improved Ash Storage

When the monthly interest rate for capital invested in improved ash storage is
increased by 50% (45% vs. 3% in the base run), the ARR decreases by 27 percentage
points to 150% and the MRR decreases by 40 percentage points to 225%. This observed
decrease in the rates of return to improved ash results from an increase in the cost of
adopting the improved ash storage, while the benefits (52.4 kg of gain 'saved") remain
unchanged.

When the monthly interest rate for capital invested in improved ash storage is
decreased by 50% (1.5% vs. 3% in the base run), the ARR increases by 30 percentage
points to 207% and the MRR increases by 45 percentage points to 310%. This observed
increase in the rates of return to improved ash is expected because the benefits (52.4 kg
of gain 'saved") have not changed, but the cost of adopting the improved ash storage
technology has decreased.

Triple Bag Storage

When the monthly interest rate for capital invested in triple bag storage is
increased by 50%, the ARR decreases by 21 percentage points to 95% and the MRR
remains dominated. This observed decrease in the rate of return to triple bagging
results from an increase in the cost of triple bag storage, while the benefits (61.3 kg of
gain "saved") remain unchanged.

When the monthly interest rate for capital invested in triple bag storage is
decreased by 50%, the ARR increases by 23 percentage points to 139% and the MRR

increases by 4.2 percentage points to 4.2%. This observed increase in the rates of return

128
to triple bag storage is expected because the benefits (61.3 kg of gain 'saved") have not

changed, but the cost of adopting the triple bag storage technology has decreased.
Solar Heater with Triple Bag Storage

When the monthly interest rate for capital invested in the solar heater with triple
bagging storage is increased by 50%, the ARR decreases by 18 percentage points to 72%
and the MRR remains dominated. This observed decrease in the ARR to the solar
heater with triple bag storage results from an increase in the cost of adopting the
technology, while the benefits (61.3 kg of gain 'saved") remain unchanged.

When the monthly interest rate for capital invested in the solar heater with triple
bagging storage is decreased by 50%, the ARR increases by 21 percentage points to
111% and the MRR remains dominated. This observed increase in the ARR to the
solar heater with triple bag storage results because the benefits (61.3 kg of gain ”saved”)
have not changed, but the cost of adopting the solar heater with triple bag storage
technology has decreased.

Rug 6; Solar Heater with Trip le Bag Technology Provides 100% Protection

In the base run analysis, the protection level provided by the solar heater with
triple bagging storage technology was set equal to the triple bagging storage technology
because on-farm demonstration trials of the improved storage technologies showed that
the two technologies were equally effective (Table 3.5). Intuitively one would expect that
losses would be lower for gain protected by the solar heater with triple bag technology
compared to triple bagging alone, because the solar heater kills all bruchids before the

gain is put into plastic bags. Laboratory experimental results/ data suggest that the solar

129

heater with triple bagging storage technology provides 100% protection“. Run 6
analyses the profitability of the solar heater with triple bagging technology, under the
assumption of 100% protection. Since this assumption only affects the profitability of
the solar heater with triple bag technology, Run 6 applies to only this technology (Table
5.10).
Solar Heater with Triple Bag Storage

When the solar heater with triple bag technoloy protection is assumed to be
100%, the ARR to the solar heater with triple bag storage increases 56 percentage points
to 146% and the MRR (relative to triple bagging) increases 35 percentage points to
35%.
5.2.2.3 Storage for Home Consumption: Summary
Benefit Parameters

The sensitivity analysis shows that for an "advanced” farmer storing his/ her total
crop for home consumption, the rates of return to the improved ash, and to a lesser
extent, triple bagging storage technologies are most affected by the assumed level of
losses using farmers’ current storage technology. When the assumed level of farmers’
losses was increased from 7 to 10.5%, the improved ash technology gave an ARR
(MRR) of 268% (403%), compared to 177% (265%) in the base run. When the
assumed level of farmers’ losses was increased from 7 to 10.5%, the triple bagging
technology gave an ARR (MRR) of 177% (dominated), compared to 116% (dominated)
in the base run. On the other hand, the when the assumed level of farmers’ losses was

decreased from 7 to 3.5%, the improved ash technology gave an ARR (MRR) of 236%

 

“A portion of the ”losses" observed in the on-farm demonstration / trial were likely
caused by bruchids during the post-harvest period, prior to heating and placing the gain
in triple bags.

130
(354%), compared to 177% (265%) in the base run. When the assumed level of farmers’

losses was decreased from 7 to 3.5%, the triple bagging technology gave an ARR (MRR)
of 169% (35%), compared to 116% (dominated) in the base run.
Similarly, relatively small changes (+ /- 25%) in cowpea gain price resulted in

relatively large differences in their profitability. When the market price of com gain

 

increased from 117 to 146.25 CFA/kg, the improved ash technology gave an ARR
(MRR) of 246% (369%), compared to 177% (265%) in the base run. When the market

price of cowpea gain increased from 117 to 146.25 CFA/kg, the triple bagging

 

technology gave an ARR (MRR) of 170% (18%), compared to 116% (dominated) in the
base run. On the other hand, when the market price of cOWpea gain decreased from
117 to 87.75 CFA/kg, the improved ash technology gave an ARR (MRR) of 108%
(162%), compared to 177% (265%) in the base run. When the market price of cowpea
gain decreased from 117 to 87.75 CFA/kg, the triple bagging technology gave an ARR
(MRR) of 62% (dominated), compared to 116% (dominated) in the base run.
Interestingly, the efficacy of the improved storage technologies affects their
profitability to a lesser extent than other factors. Only the profitability of the improved
ash technology is affected by variations in the assumed/ estimated level of protection.
Both the triple bagging and solar heater with triple bagging remained dominated by
improved ash storage-even when their assumed level of protection is increased from 3 to
1.5%. By adopting improved ash storage, farmers capture the geatest benefit from
improved storage technology--minimal additional benefits are gained from marginal

additional improvements in storage protection.

131

s a ct

The sensitivity analysis of the cost of the improved storage technologies also
geatly influence their profitability. Relatively small variations (+ /- 25%) in their cost
generate relatively large differences in their feasibility. Therefore, farmer adoption will
require farmer access to the necessary inputs (e.g., earthenware cannaries, plastic bags)
at modest prices. For example, if plastic bags became available at a lower cost (25 %
lower), then this storage method would be attractive to more "advanced" farmers.

Finally, the assumed opportunity cost of capital (3% / month) assigied to the
improved storage technologies did not have a large impact on the profitability of the
improved ash or triple bag storage technologies. However, if a farmer were required to
borrow cash (or valued his/her own capital) at a very high interest (i.e., 100% annually)
then this would geatly reduce his/her incentive to adopt improved storage.
5.2.2.4 Storage for Future Sale: Base Run

Currently, a few high cowpea production household produce enough cowpeas to
meet consumption needs and still have sufficient surplus gain for speculation. As new
high-yielding varieties become available more farmers will gow cowpeas mainly as a cash
crop, and may wish to store the crop until prices are highest in July-August.
Experiments show high levels of bruchid damage after several months of storage,
suggesting that ”advanced” farmers with large inventories who store for 6 or more
months (until the cowpea gain price peaks) using their current storage technology (e.g.,
sacks) will experience large losses. Thus, these farmers may benefit from investing
in/adopting the improved cowpea storage technologies.

Assuming ”advanced" farmers store 200 kg of their harvest for speculation using

their current storage technology, their inventories would be reduced to only 0.6 kg after 9

 

 

132
months (November through July) in storage (when the market price peaks at 196

CFA/kg), due to bruchid damage. By investing in improved cowpea storage technology,
these households could reduce storage losses, which would enable them to extend their
period of speculation (i.e., the ability to earn profits by storing and selling when the price
is at its peak).

Because "advanced" farmers tend to have good access to extension services, the
following analysis assumes they will use the improved storage technologies correctly and
receive all (100%) of the potential benefits.

”Advanced” farmers adopting the improved storage technologies will gain an
additional 180.9 and 190.1 kg of cowpea gain after nine months of storage using the
improved ash and either the triple bag or solar heater with triple bag technologies,
respectively.

To assess the likelihood that “advanced” farmers would find these new
technologies economically viable (profitable), the average and marginal rate of return to
investing in each of the improved COWpea storage technologies were estimated (Table
5.11).

These results show that when an "advanced” farmer values his/her own funds or
borrows the funds at a monthly interest rate of 3% (base run), adopting the improved
ash, triple bag, and solar heater with triple bag storage technology implies a 2,098, 1,440,
and 1.178% average rate of return (ARR), respectively, to gain stored for future sale
(i.e., 9 months of storage). These results suggest that adopting any one of the alternative
improved/new gain storage technologies would by economically attractive for the
"advanced” farmer, since all far exceed the 50% minimum rate of return proposed by

CIMMYT (1988).

133

Compared to the ”advanced" farmers’ current storage technology, improved ash
gives a marginal ROR of 3,187 %. In other words, by investing an additional 1,075 CFA
in ash storage, benefits are increased to 34,263 CFA. Thus, the marginal ROR (34,263
divided by 1,075 CFA) equals 3,187%--suggesting a very attractive investment option.

The triple bag storage has a high (1,440%) ARR, it has a MRR of only 124%, yet
still geater than the minimal acceptable 50% as suggested by CIMMYT. In order to
adopt the triple bagging storage technology, the farmer would have to invest an
additional 806 CFA (above the cost of the ash technology); but he/she would earn only
998 CFA more profit (net benefits) from investing the in the triple bag technology,
compared to ash storage.

Similarly, although the solar heater with triple bagging technology has a high
(1,178%) ARR, it generates less net benefits (~497)--compared to the triple bagginguand
is therefore, dominated by the triple bag technology.

In summary, the base run analysis shows that although all three improved storage
technologies give attractive ARRs, the MRR analysis shows that if an ”advanced" farmer
could adopt improved ash storage, he/she would earn a very large (3,187%) rate of
return on this investment. And, if the farmer could invest an additional 806 CFA in
triple bag storage, he/ she would earn an additional 124% rate of return on this
investment. Yet, it would be irrational for the farmer to invest in the solar heater with
triple bag storage, since it is dominated by triple bag storage. These results are largely
driven by the storage loss data used in the analysis. Available experimental data (Table
3.5) show that the triple bag and solar heater with triple bag technology are equivalent in

terms of loss reduction, but the latter is more costly to adopt.

134

Table 5.11 Partial Budget and Rate of Returns Analysis of Improved Cowpea Storage
Technologies for Grain Intended for Future Sale‘: Base Run for Advanced

 

 

 

 

 

 

 

Farmers.
4-
Farmers’ Improved Triple Solar Heater
Current Ash Bag & Triple Bag
Practice” Storage‘ Storage‘1 Storage‘
Grain Saved' (kgs) 0.6 180.9 190.1 190.1
Partial Budget (CFA)
Gross Benefits“ 118 35,456 37,260 37,260
Total Costs“ 1,613 8,063 2,419 3,414
Annual Costs‘ 538 1,613 2,419 2,916
Net Benefits -420 33,843 34,841 34,344
(goss benefits minus
annual costs)
Marginal Benefits and
Costs (CFA)
Additional Net Benefits NA 34,263 998 497
Additional Annual Costs NA 1,075 806 497
Rate of Returns (%)
Average -78 2,098 1,440 1,178
Marginal NA 3,187 124 D
‘200 kg of com gain put into storage for nine months.
I’4 cloth sacks.
‘4 cannaries.
‘12 plastic bags.

‘1 solar heater shared by 10 households plus 12 plastic bags.

'Additional kg of cowpea gain as a result of using the improved technologies.
‘Cowea grain (kg) ”saved" valued at month 10 (August) market price of 196 CFA/kg.
hIncludes opportunity cost of capital (3% per month) for 10 months (Nov. - August).
iTotal costs/ useful life of the technology.

NA = not applicable; D = dominated.

135
5.2.2.5 Storage for Future Sale: Sensitivity Analysis

Although the base run represents the "best estimate" of the average and marginal
returns to cowpea gain storage technologies, sensitivity analysis is conducted to test the
variability in rate of return, associated with alternative assumptions regarding the data
values used in these analyses. Further, given that some data used in the analysis are
based on "informed assumptions” rather than empirical findings, sensitivity analysis
indicated the degee to which each assumption affects the results.

Six parameters42 were identified as having a sigiificant influence on the rates of
return to the improved gain storage technologies (Tables 5.12 - 5.14). Six sensitivity
analyses are presented below. Each analysis assesses the impact of altering one of the
six ”critical parameters" on the rate of return to investing in the three new technologies--
improved ash storage, triple bagging storage, and solar heater with triple bag storage.
Run 1: Famers’ Current Level of Storage Losses

In the base run analysis, annual storage losses were estimated using a logistic
function (Equation 5.1), based on farm-level storage loss data collected in March 1990.
By testing the robustness of these estimates, sensitivity analysis determines to what
degee the rate of return estimate depends on the accuracy of these data.

Improved Ash Storage

In the base run analysis, "advanced” farmers adopting improved ash storage

earned a 2,098% ARR and a 3,187% MRR on their investment (Table 5.11). When the

assumed level of ”advanced” farmers’ current storage losses is increased by 50% (10.5 %

 

“The six parameters varied in the sensitivity analysis include the household’s current
level of gain losses using his/her traditional storage method, the losses associated with
using the improved technologies, technology cost, market price of cowpea gain, the
opportunity cost of capital, and a premium price paid for improved quality cowpea gain.

 

136

of the stock lost by the fourth month in storage vs. 7% in the base run), the ARR
increases 6 percentage points to 2,104% and the MRR to ash storage increases 18
percentage points to 3,205%. This is because when household losses are increased by
50%, the amount of gain "saved" using farmers’ current storage technology is reduced
(0.6 kg in the base run vs. 0.15 kg) and consequently makes the improved ash technology
marginally more attractive (180.9 kg ”saved" in the base run vs. 181.4 kg).

In contrast, when the assumed level of household losses are decreased by 50%
(3.5% of the stock lost by the fourth month in storage vs. 7% in the base run), the ARR
decreases 42 percentage points to 2,056% and the MRR to ash storage decreases 127
percentage points to 3,060%. This is because when household losses are reduced by
50%, the amount of gain ”saved” using farmers’ current storage technology is increases
(0.6 kg in the base run vs. 4.1 kg), which makes the improved ash technology marginally
less attractive (180.9 kg "saved” vs. 177.4 kg).
Triple Bag Storage

In the base run, ”advanced" farmers adopting triple bag storage earned a 1,440%
ARR and the MRR was 124% (Table 5.11). When the assumed level of ”advanced”
farmers’ current storage losses is increased by 50%, the ARR increases 4 percentage
points to 1,444% and the MRR remains 124%. The MRR does not increase because
when assumed household losses are increased by 50%, both the improved ash (180.9 kg
”saved” in the base run vs. 181.4 kg) and triple bagging (190.1 kg ”saved" in the base run
vs. 190.6 kg) technology save an additional 0.5 kg of gain. Therefore, triple bagging is
only improved on the average, but not marginally.

When ”advanced” farmers’ assumed level of losses is decreased by 50%, the ARR

decreases 28 percentage points to 1,412% and the MRR to triple bagging remains 124%.

 

137
This is because when household losses are decreased by 50%, both the improved ash

(180.9 kg ”saved" in the base run vs. 177.4 kg) and triple bagging (190.1 kg in the base
run vs. 186.6 kg) technologies ”save" 3.5 kg less additional gain and therefore, the triple
bag technology is only less attractive on the average, but not on the margin.

Solar Heater with Triple Bag Storage

In the base run, "advanced" farmers adopting the solar heater with triple bagging
storage earned a 1,178% ARR, but the MRR was dominated by triple bag storage (Table
5.11). When the assumed level of "advanced” farmers’ current storage losses is increased
by 50%, the ARR increases 3 percentage points to 1,181% and the MRR remains
dominated. This is because when household losses are increased by 50%, all three
improved technologies "save” an additional 0.5 kg of gain and therefore, solar heater
with triple bagging is only improved on the average (190.1 kg in the base run vs. 190.6
kg) and not on the margin.

When ”advanced" farmers’ assumed losses are decreased by 50%, the ARR
decreases 24 percentage points to 1,154% and the MRR to solar heater with triple bag
storage remains dominated. This is because when household losses are decreased by
50%, all three improved technologies ”save" 3.5 kg less additional gain and therefore,
the solar heater with triple bagging is only less attractive on the average (190.1 kg in the
base run vs. 186.6 kg), but not on the margin.

u : rvdto eTec 010 ct in

In the base run analysis, the level of protection data were based on on-farm

demonstrations of the improved storage technologies. Because so few trials were

conducted, the sensitivity of the returns in the base run to the assumed protection levels

are evaluated.

 

138

Improved Ash Storage

When the estimated level of losses using the improved ash storage is increased by
50% (9% of the stock lost by the third month in storage vs. 6% in the base run), the
ARR decreases by 41 percentage points to 2,057% and the MRR decreases by 62
percentage points to 3,125%. This observed decrease in returns to adopting ash storage
occurs because assuming 50% more "losses" under the improved ash technology results in
less gain "saved" (177.5 kg vs. 180.9 kg in the base run), which is valued at the month 10
(August) market price of 196 CFA/kg. Since the traditional storage practice (i.e., cloth
sacks) is being replaced by the improved ash storage, an increase in the value of this
parameter (i.e., less effective) will result in a lower rate of return. By setting a lower
protection level for the improved ash storage technology, the improved ash storage
technology will certainly appear worse than in the base run.

When the estimated level of losses using improved ash storage is decreased by
50% (3% of the stock lost by the third month in storage vs. 6% in the base run), the
ARR increases by 40 percentage points to 2,138%, and the MRR increases by 60
percentage points to 3,247%. Setting a higher protection level for the improved ash
storage technology, results in more gain ”saved" (184.2 kg vs. 180.9 kg in the base run),
which is valued at the month 10 (August) market price of 196 CFA/kg.
Triple Bag Storage

When the estimated level of losses using triple bagging storage is increased by
50% (i.e., 4.5% of the stock lost by the third month in storage), the ARR decreases by
27 percentage points to 1,413% and the MRR increases by 41 percentage points to
165%. Intuitively, one would believe that the marginal returns to the triple bag storage

technology should also decrease when the level of storage losses using triple bag storage

139

are increased by 50%. Yet, the MRR increases because the percentage decrease in
“saved” gain (1.82%) using triple bag storage (186.7 kg vs. 190.1 kg in the base run) is
less than the percentage decrease in ”saved“ gain (1.92%) using improved ash storage
(177.5 kg vs. 180.9 kg in the base run).

When the estimated level of losses using triple bagging storage is decreased by
50% (1.5% of the stock lost by the third month in storage vs. 3% in the base run), the
ARR increases by 14 percentage points to 1,454% and the MRR decreases by 39
percentage points to 85%. Intuitively, one would believe that the marginal returns to the
triple bag storage technology should also increase when the level of storage losses using
triple bag storage are decreased by 50%. Yet, the MRR increases because the
percentage increase in "saved” gain (0.89%) using triple bag storage (191.8 kg vs. 190.1
kg in the base run) is less than the percentage increase in "saved" gain (1.79%) using
improved ash storage (184.2 kg vs. 180.9 kg in the base run).
Solar Heater with Triple Bag Storage

When the estimated level of solar heater with triple bag storage losses is
increased by 50% (4.5% of the stock lost by the third month in storage vs. 3% in the
base run), the ARR decreases by 23 percentage points to 1,155% and the MRR remains
dominated. Setting a 50% lower protection level for the solar heater with triple bagging
technology, results in less gain "saved” (186.7 kg), and in turn, a lower rate of return.

When the estimated level of the solar heater with triple bag storage losses is
decreased by 50% (1.5% of the stock lost by the third month in storage vs. 3% in the
base run), the ARR increases by 11 percentage points to 1,189% and the MRR remains
dominated. Setting a 50% higher protection level for the solar heater with triple bagging

technology, results in more gain ”saved” (191.8 kg), and in turn, a higher rate of return.

 

 

140

W
In the base run analysis, although most cost figures of the improved storage

technology were directly quoted from CRSP documents, there is still a possibility that
these costs were under/ over estimated. The cost variable is varied to estimate how
sensitive the returns to improved gain storage technologies are to higher or lower total
input costs.
Improved Ash Storage

When the total input cost of the improved ash storage technology is increased by
25%, the ARR decreases by 439 percentage points to 1,659% and the MRR decreases by
696 percentage points to 2,491%. This observed decrease in the rate of return to
improved ash are expected because the benefits (180.9 kg of gain ”saved") have not
changed, but the cost of adopting the improved ash storage technology is now 25%
higher.

When the total input cost of the improved ash storage technology is decreased by
25%, the ARR increases by 732 percentage points to 2,830% and the MRR increases by
1,092 percentage points to 4,279%. This observed increase in the rate of return to
improved ash is again expected because the benefits (180.9 kg of gain 'saved') have not
changed, but the cost of adopting the improved ash storage technology is now 25%
lower.
Triple Bag Storage

When the total input cost of the triple bag storage technology is increased by
25%, the ARR decreases by 308 percentage points to 1,132% and the MRR decreases by

45 percentage points to 79%. This observed decrease in the ARR and MRR to triple

141
bagging is expected because the benefits (190.1 kg of gain “saved') have not changed,

but the cost of adopting the triple bag storage technology is now 25% higher.

When the total input cost of the triple bag storage technology is decreased by
25%, the ARR increases by 514 percentage points to 1,954% and the MRR increases by
75 percentage points to 199%. This observed increase in the ARR and MRR to triple
bagging is again expected because the benefits (190.1 kg of gain 'saved") have not
changed, but the cost of adopting the triple bag storage technology is now 25% lower.
Solar Heater with Triple Bag Storage

When the total input cost of the solar heater with triple bag storage technology is
increased by 25%, the ARR decreases by 256 percentage points to 922% and the MRR
remains dominated. The ARR to the solar heater with triple bagging decreases because
the benefits (190.1 kg of gain "saved") have not changed, but the cost of adopting the
solar heater with triple bag storage technology is now 25% higher.

When the total input cost of the solar heater with triple bag storage technology is
decreased by 25%, the ARR increases by 426 percentage points to 1,604% and the MRR
remains dominated. This observed increase in the ARR is again expected because the
benefits (190.1 kg of gain ”saved”) have not changed, but the cost of adopting the solar
heater with triple bag storage technology is now 25 % lower.

Ru : a ct 'ceofCo eaGa'

In the base run analysis, the market price for cOWpea gain was based on two
years of price data (1989-1990) collected by the TLU. Because market prices vary across
years and across markets, the gain price is varied to estimate how sensitive the returns
to improved gain storage technologies are to price.

Improved Ash Storage

 

142
When the market price for ma gain is increased by 25%, (from 196 to 245

CFA/kg) the ARR increases by 550 percentage points to 2,648% and the MRR
increases by 822 percentage points to 4.009%. This observed increase in the rate of
return to improved ash are expected because the benefits (180.9 kg of gain "saved” times
a higher price) have increased, but the cost of adopting the improved ash storage
technology has not changed.

When the market price for cowpea gain is decreased by 25%, (from 196 to 147
CFA/kg) the ARR decreases by 549 percentage points to 1,549% and the MRR
decreases by 822 percentage points to 2,365%. This observed decrease in the rate of
return to improved ash is again expected because the benefits (180.9 kg of gain "saved"
times a lower price) have decreased, but the cost of adopting the improved ash storage
technology has not changed.

Triple Bag Storage

When the market price for cowpea gain is increased by 25%, the ARR increases
by 385 percentage points to 1,825% and the MRR increases by 56 percentage points to
180%. This observed increase in the rate of return to triple bagging is expected because
the benefits (190.1 kg of gain ”saved” times a higher price) have increased, but the cost
of adopting the triple bag storage technology has not changed.

When the market price for cowpea gain is decreased by 25%, the ARR
decreases by 385 percentage points to 1,055% and the MRR decreases by 56 percentage
points to 68%. This observed decrease in the rate of return to triple bagging is again
expected because the benefits (190.1 kg of gain "saved” times a lower price) have
increased, but the cost of adopting the triple bagging storage technology has not changed.

Solar Heater with Triple Bag Storage

 

 

143

When the market price for cowpea gain is increased by 25%, the ARR increases
by 319 percentage points to 1,497% and the MRR remains dominated. This observed
increase in the rate of return to the solar heater with triple bagging is expected because
the benefits (190.1 kg of gain ”saved" times a higher price) have increased, but the cost
of adopting the solar heater with triple bag storage technology has not changed.

When the market price for cowpea gain is decreased by 25%, the ARR
decreases by 320 percentage points to 858% and the MRR remains dominated. This
observed decrease in the rate of return to the solar heater with triple bagging is again
expected because the benefits (190.1 kg of gain "saved” times a lower price) have
increased, but the cost of adopting the solar heater with triple bagging storage technology
has not changed.

5: teest ate oui Cso it

In the base run analysis, the opportunity cost of capital is set at a 3 percent per
month interest rate, representing the interest rate that farmers would have to pay if they
borrowed from money lenders or informal credit institutions. The opportunity cost of
capital is an additional cost to the farmer of adopting any of the improved storage
technologies and affects the returns to the improved/new technologies. Because farmers
may have to pay more/less interest to finance their investment the interest is varied to
test how sensitive the returns to improved storage are to the interest rate.

Improved Ash Storage

When the monthly interest rate for capital invested in improved ash storage is
increased by 50% (from 3 to 4.5%), the ARR decreases by 296 percentage points to
1,802% and the MRR decreases by 444 percentage points to 2,743%. This observed

decrease in the rate of return to improved ash results from an increase in the cost of

 

144

adopting the improved ash storage, while the benefits (180.9 kg of gain 'saved") remain
unchanged.

When the monthly interest rate for capital invested in improved ash storage is
decreased by 50% (from 3 to 1.5%), the ARR increases by 347 percentage points to
2,445% and the MRR increases by 517 percentage points to 3,704%. This observed
increase in the rate of return to improved ash is expected because the benefits (180.9 kg
of gain 'saved") have not changed, but the cost of adopting the improved ash storage
technology has decreased.

Triple Bag Storage

When the monthly interest rate for capital invested in triple bag storage is
increased by 50%, the ARR decreases by 207 percentage points to 1,233% and the MRR
decreases by 30 percentage points to 94%. This observed decrease in the rate of return
to triple bagging results from an increase in the cost of triple bag storage, while the
benefits (190.1 kg of gain "saved”) remain unchanged.

When the monthly interest rate for capital invested in triple bag storage is
decreased by 50%, the ARR increases by 244 percentage points to 1,684% and the MRR
increases by 35 percentage points to 159%. This observed increase in the rate of return
to triple bag storage is expected because the benefits (190.1 kg of gain 'saved") have not
changed, but the cost of adopting the triple bag storage technology has decreased.

Solar Heater with Triple Bag Storage

When the monthly interest rate for capital invested in the solar heater with triple

bagging storage is increased by 50%, the ARR decreases by 172 percentage points to

1,006% and the MRR remains dominated. This observed decrease in the ARR to the

 

 

145

solar heater with triple bag storage results from an increase in the cost of adopting the
technology, while the benefits (190.1 kg of gain 'saved') remain unchanged.

When the monthly interest rate for capital invested in the solar heater with triple
bagging storage is decreased by 50%, the ARR increases by 202 percentage points to
1,380% and the MRR remains dominated. This observed increase in the ARR to the
solar heater with triple bag storage results because the benefits (190.1 kg of gain
”saved”) have not changed, but the cost of adopting the solar heater with triple bag
storage technology has decreased.

Run 6: Solar Heater with Iriple Bag Storage Provides 100% Protectioa

In the base run analysis, the solar heater with triple bagging storage technology’s
protection level was set equal to the triple bagging storage technology because data from
the on-farm demonstrations of the improved storage technologies show the two
technologies to be equally effective (Table 3.5). Intuitively one would expect that using
the solar heater with triple bag technology would result in lower losses than triple
bagging alone because the bruchids are first killed before the gain is put into plastic
bags, and laboratory experimental results/data suggest that the solar heater with triple
bagging storage technology provides 100% protection. Run 6 analyses the profitability of
the solar heater with triple bagging technology, under the assumption of 100%
protection. Since this assumption only affects the profitability of the solar heater with
triple bag technology, Run 6 applies to only this technology (Table 5.14).

Solar Heater with Triple Bag Storage

When the solar heater with triple bag technology protection is 100%, the ARR to

the solar heater with triple bag storage increases 62 percentage points to 1,244% and the

MRR (i.e., compared to triple bagging) increases 267 percentage points to 267%.

 

146

W

In the base run analysis, the gain "saved" (benefits to) using each of the
improved storage technologies was valued at the stated peak market price. To account
for farmer and consumer preferences for undamaged (without holes or not "weevily'
favored) COWpea gain, a premium of 20% above the market price is given to the gain
”saved" using the improved storage technologies.
Improved Ash Storage

When a 20% premium is paid for undamaged cowpea gain, the ARR to
improved ash storage increases 440 percentage points to 2,538% and the MRR increases
660 percentage points to 3,847%.
Triple Bag Storage

When a 20% premium is paid for undamaged COWpea gain, the ARR to triple
bag storage increases 308 percentage points to 1,748% and the MRR increases 44
percentage points to 168%.
Solar Heater with Triple Bag Storage

When a 20% premium is paid for undamaged cowpea gain, the ARR to the
solar heater with triple bag storage increases 255 percentage points to 1,433 %, but the
MRR remains dominated.
5.2.2.6 Storage for Future Sale: Summary

The sensitivity analysis shows that for an "advanced” farmer storing 200 kg for
speculation, the rates of return to improved ash and triple bagging are most affected by
variations in input cost, the market price of COWpea gain and the Opportunity cost of

capital assigned to the investment.

 

147

Cost a ete

The returns to the improved ash and triple bag technologies are most sensitive to
fluctuations (+ /- 25%) in their cost. When the input cost of improved ash was increased
25% from 1,200 to 1,500 CFA, the ARR (MRR) diminished to 1,659% (2,491%),
compared to 2,098% (3,187%) in the base run. When the input cost of triple bagging
was increased 25% from 1,800 to 2250 CFA, the ARR (MRR) diminished to 1,132%
(79%), compared to 1,440% (124%) in the base run. On the other hand, when the input
cost of improved ash was decreased 25% from 1,200 to 900 CFA, the ARR (MRR)
increased to 2,830% (4,279%), compared to 2,098% (3,187%) in the base run. When the
input cost of triple bagging was decreased 25% from 1,800 to 1,350 CFA, the ARR
(MRR) increased to 1,954% (199%), compared to 1,440% (124%) in the base run.

Similarly, relatively small changes in cowpea gain resulted in relatively large
differences in the technologies profitability. When the market price was increased 25%,
from 196 to 245 CFA/kg, the improved ash technology gave an ARR (MRR) of 2,648%
(4,009%), compared to 2,098% (3,187%) in the base run. When the market price of
cowpea gain increased from 196 to 245 CFA/kg, the triple bagging technology gave an
ARR (MRR) of 1,825% (180%), compared to 1,440% (124%) in the base run. On the
other hand, when the market price of cowpea gain decreased from 196 to 147 CFA/kg,
the improved ash technolog' gave an ARR (MRR) of 1,549% (2,365%), compared to
2,098% (3,187%) in the base run. When the market price of cOWpea gain decreased
from 196 to 147 CFA/kg, the triple bagging technology gave an ARR (MRR) of 1,055%
(68), compared to 1,440% (124%) in the base run. Furthermore, the gain prices used in
the analysis were market prices and not farmgate prices (the price farmers would receive

for the sale of their gain) because this data was not available. Thus, the estimated

 

148

profitability of the technologies is inflated, if the farmgate prices are sigiificantly below
market prices. Also, gain prices vary throughout the season and across markets. Thus,
the farmer’s decision to adopt an improved storage technology will depend on farmers’
future price expectations at harvest when they must decide whether to adopt improved
storage.

Finally, the assumed opportunity cost of capital (3% / month) assigied to the
improved storage technologies did have a large impact on the profitability of the
improved ash and triple bag storage technologies. When the opportunity cost of capital
was increased 50%, from 3 to 4.5% per month, the improved ash technology gave an
ARR (MRR) of 1,802% (2,743%), compared to 2,098% (3,187%) in the base run. When
the opportunity cost of capital was increased 50%, the triple bagging technology gave an
ARR (MRR) of 1,233% (94%), compared to 1,440% (124%) in the base run. On the
other hand, when the opportunity cost of capital was decreased 50%, from 3 to 1.5% per
month, the improved ash technology gave an ARR (MRR) of 2,445% (3,704%),
compared to 2,098% (3,187%) in the base run. When the opportunity cost of capital was
decreased 50%, the triple bagging technology gave an ARR (MRR) of 1,684% (159%),
compared to 1,440% (124%) in the base run.

e f t a eters

Interestingly, the rates of return to the improved ash and triple bagging
technologies were not very sensitive to variations (+ /- 50%) in the level of protection
generated by either the farmers’ current storage practices (sacks) or the improved
storage technologies. When the assumed level of farmers’ losses was increased from 7 to
10.5%, the improved ash storage technology gave an ARR (MRR) of 2,104% (3,205%),

compared to 2,098% (3,187%) in the base run. When the assumed level of farmers’

 

149
losses was increased 50%, the triple bagging storage technology gave an ARR (MRR) of

1,444% (124%), compared to 1,440% (124%) in the base run. On the other hand, when
the assumed level of farmers’ losses was decreased from 7 to 3.5%, the improved ash
storage technology gave an ARR (MRR) of 2,056% (3,060%), compared to 2,098%
(3,187%) in the base run. When the assumed level of farmers’ losses was decreased
50%, the triple bagging storage technology gave an ARR (MRR) of 1,412% (124%),

compared to 1,440% (124%) in the base run.

150

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153
5.3 The Store vs. Selling Decision

Risk and the Qppgrtugity Cost of 39mm g gram Inventories

As in most developing countries, the market price of cowpeas in the Cameroon
increases substantially after harvest. This phenomena suggests that farmers could profit
by storing grain and selling it later in the season when post-harvest prices increase to
their seasonal high level. For example, the previous analysis indicated that ”advanced"
farmers who stored 200 kg of cOWpeas for future sale, using improved ash and triple bag
storage, would have earned attractive average and marginal rates of return, compared to
their existing storage technology. But this analysis didn’t take into account either the
risk associated with adopting these improved storage technologies or the opportunity cost
of the income farmers would have foregone, had they chosen to hold their inventories
several months as required to capture the higher late-season market price.
Risk

Storing stocks for future sale exposes farmers to both ”storage” and ”price" risk.
For example, under optimal conditions, farmers adopting the improved storage
technologies (e.g., triple plastic bags) will reduce their insect infestation. But, under
actual farm-level storage conditions, rodents may chew through the hermetically sealed
bags--allowing reinfestation. If this were to occur, the benefits to adopting triple bag
storage would be substantially less than previously projected. Similarly, while historical
data used in this analysis indicates that prices rise over the season, the magnitude of the
monthly price rise varies between market and between years. In years of short supply
(poor harvest), the prices rise will exceed the mean values used; and in years of

abundant supply (good harvest) the price rise will be below the mean. Hence, assuming

 

154
that poor farmers are risk averse, they would likely discount the projected potential

benefit—given these elements of risk.

0n the other hand, by selling at harvest a farmer can obtain cash immediately,
thereby improving his/her cash flow. In addition, he/ she is not forced to borrow cash at
high informal credit market rates in order to cover outstanding debts and immediate
household needs; while waiting to sell his/her grain at the seasonal high price.
Qppogunity Cost of §tored Inventories

By postponing sale at harvest to obtain a greater future benefit, a farmer forgoes
the opportunity to immediately use the cash he/she could have gained by selling at
harvest. Therefore, in order to compare the “true" value of this future income to the
value of the income he/she could have earned by selling at harvest, this future income
must be discounted.

Since the previous results indicated that the most profitable new storage
technology was improved ash storage, the following analysis only evaluates the
profitability of this technology, when an opportunity cost is assigned to the value of the
' farmers’ stored grain. In this analysis, projected future income (net returns) is
discounted by two alternative rates, 18% (1.5% per month) and 36% (3.0% per month).
All other costs and benefit streams are as specified in the base analysis presented earlier.

Tables 5.15 and 5.16 present the net present value (NPV) of the future income
that a farmer would earned, if he/she sold the crop in November through October. The
respective NPVs may be interpreted as the current value (November) of the respective

future incomes (net returns). For storage for future sale to more profitable than sale at

 

155

harvest, the NPV in a given month must be greater than the net return that a farmer
could have earned by selling at harvest (November).

The results show that for an "advanced" farmer using improved ash technology to
store 200 kg of cowpeas, under the assumption that the opportunity cost of capital is 3%
(e.g., discount rate), the NPV of stored grain sold in all months is below the value of the
net returns he/she would have earned if he/she had sold the crop at harvest (Figure 5.3
and Table 5.15).

On the other hand, when the discount rate is reduced to 1.5% per month, the
NPV of the future net returns is less that the net returns that a farmer could have
earned by selling at harvest in all months except August. This suggests that only if a
farmer stored and sold his crop in August, would he/ she have earned more profit
(29,589 CFA) than by selling at harvest (27,600 CFA). But, the value of this additional
profit was equal to approximately 2,000 CFA-compared to an investment cost of 6,000
CFA (Figure 5.4 and Table 5.16).

These results suggest provide insights as to why farmers typically sell their
cowpea surpluses at harvest. Storage for future sale exposes farmers to risk and they are
short of cash at harvest. Therefore, few poor farmers can afford to store in anticipation

of the modest and uncertain profits associated with storing for speculation.

20.00
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156

 

 

 

 

 

 

 

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157

 

 

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CHAPTER 6 SUMMARY AND CONCLUSIONS

This chapter is divided into three sections. The first summarizes the thesis and
research findings for the benefit-cost analysis, noting important issues/points in
interpreting the results. The second compares the rates of return estimated for the
improved storage technologies under both the “traditional" and ”advanced" farmers’
situation/conditions, and reviews possible implications for the improved storage
technologies developed. The final section suggests additional data that should be
collected to confirm these results; describes the study’s limitations and proposes future
socioeconomic research to better inform farmer storage issues; and considers the policy

implications of extending these improved gain storage technologies.

6.1 Thesis Summary

Scientists and policy makers have focused a great deal of attention on reducing
post-harvest food losses as part of the overall strategy for coping with possible future
food shortages in the developing world. Out of this concern, several international and
national research institutions have conducted research to quantify the level and causes of
on-farm food gain storage losses. Inadequate storage facilities have attributed to/been
blamed for some /part of the gain losses.

Much of the research on improving small-farm gain storage has involved surveys
and trials to assess the magnitude of current losses. Based on a review of the literature,

the studies reviewed can be roughly separated into two goupsuthose claiming that on-

160

161

farm gain storage losses are high (30-90%) and those supporting low (5-10%) losses.
These accounts suggest that it is diffith to generalize regarding storage losses. The
magnitude of storage losses varies by crop and from region-to-region. Therefore, crop
location and system specific analysis is needed to accurately estimate storage losses for a
particular case. Furthermore, the correlation between the magnitude of "actual" losses
and storage time is geatly influenced by the households’ consumption rate. Because the
amount of gain a household stores is continually declining, the losses experienced affect
a decreasing quantity of gain in storage.

In the tropics and subtropics, food gains are mostly stored using traditional
methods, which vary in their ability to insure safe storage. Farmers use numerous
traditional gain storage structures and protectants against insect pest damage to
minimize on-farm storage losses. Performance variations are typically influenced by
climate, local availability of suitable materials, labor availability, investment capital, and
local customs (McFarlane, 1988). These traditional on-farm storage methods generally
provide effective protection for the relatively small stores of gain low-resource farmers
produce.

Come are the principal gain legume crop gown in northern Cameroon.
Several parts of the plant are used by the household. COWpea gain, leaves and hay are
both home-consumed and sold. Although COWpea production accounts for only 5% of
the harvested area of the Far North Province, for many households it fills an important
niche during the ”hungy season” (July-August), since cowpeas are practically the only

”new crop” available during this early period.

162
Although research trials have produced monoculture yields of 2,000 kg/ ha,

farmers’ average yields tend to be low (300-400 kg/ ha). Part of this yield difference is
due to the fact that farmers in northern Cameroon typically intercrop cowpeas with
gains, which makes direct comparisons between monoculture and intercropped yields
inappropriate. Also, farmers are often unable to obtain inputs (i.e., high-yielding variety
seed and insecticide) needed to produce high yields under monoculture.

Several international and national research institutions have conducted cOWpea
research, focusing primarily on developing improved varieties with higher yield potential
and increased storage-pest resistance, and improved on-farm gain storage technologies.

To better understand storage constraints facing farmers, the Bean /COWpea CRSP
conducted three farmer surveys which revealed considerable variations among cOWpea
farmers in northern Cameroon, in terms of technology adoption, level of production,
household utilization and storage methods. Data collected on surveyed cowpea farmers
(1990) were used to classify farmers according to their level of adoption of improved
varieties and/ or production recommendations extended by the research-extension system.
The majority (78%) of cowpea farmers had either not adopted or not fully-adopted the
recommended improved production technology/ cropping practices". A large

proportion (47%) planted only traditional cowpea varieties, generally intercropping them

 

“If a woman was the primary person responsible for cowpea production, she
generally did not spray insecticide (82%). Farmers’ lack of access to insecticide (54%),
and the lack of access to credit to purchase inputs (16%) were the most frequently given
reasons/constraints for not using insecticide.

163

with either sorghum or millet, and did not spray insecticide on the crop in the field‘4 .
Generally, these non-adopting farmers are women who produce on average less than 100
kgs of cowpea gain, assumed primarily for home consumption.

A minority (22%) of cowpea farmers adopted the recommended improved
production technologies/practicesumonocropping an improved cowpea variety and
applying field insecticides. These farmers produced an average of 287 kgs of COWpeas
per household on 1.3 hectares.

In addition, samples of stored cowpeas were collected from all interviewed
households and assessed for storage damage. Analysis of the loss data by field practices
followed showed that farmers applying field insecticides suffered lower storage losses
than farmers who either intercropped with cotton or monocropped.

Farmers’ storage losses also varied with the storage method practiced. Most
farmers stored under 100 kg of COWpea gain. Farmers who treated their inventories
with insecticides and stored for 4 to 6 months in sacks incurred the lowest amount of
storage loss, whereas cowpea gain stored in ash (traditional ash storage method)
suffered the most damage--suggesting that farmers traditional ash storage treatment is
not effective. Finally, losses in cowpeas stored on a danki provided approximately the

same level of protection (after 4-6 months of storage) as ash--possible because cOWpea

 

“COWpea leaves are an important food item for many households. Frequently,
farmers who planted monoculture cowpeas and sprayed insecticide also intercropped
cowpeas with a gain in order to have insecticide-free cowpea leaves to eat. COWpea
leaves may be almost as important as COWpea gain to a ”traditional" farmer household.
This is not really a constraint, but rather it’s a reason for not adopting higher gain-
yielding yet lower leaf-yielding varieties which require insecticide.

164

pods provide resistance to bruchid penetration and the sun may inhibit insect population
gowth.

In 1986, scientists at Purdue University and IRA (under the auspices of the
Bean / Cowpea CRSP) initiated research to develop bruchid resistant varieties and
improve farmers’ post-harvest storage technologies. On-farm experiments in Maroua,
Cameroon demonstrated that the improved ash, triple bag and solar heater with triple
bag storage technologies effectively protected stored cowpea gain from C. maculatus
infestations.

This thesis evaluates the profitability of these technolOgies using benefit-cost
analysis to assess their potential attractiveness to different types of farmers-"traditional"
and "advanced”. Also this analysis was carried out to help guide future research efforts
to develop appropriate technologies that meet the needs of limited resource farmers.
Data from the farm surveys and on-farm trials were used to estimate cost and benefits
associated with each storage technology. Also, the analysis took into account differences
between farmer types with respect to management practices, capacity to bear risk, access
to credit and extension services, and access to both input and output markets.

Both the average (ARR) and marginal rates of return (MRR) to adopting the
improved storage technologies were calculated. The ARR indicated the percentage
increase in returns above the investment cost. The MRR assessed the incremental
profitability of a more costly technology, above and beyond the profitability of the less

costly alternative.

 

165
te '0

Several cost assumptions were incorporated into these analyses. First, the
analysis assumed that the investment cost of a ganary was zero because households do
not construct/ invest in a ganary for the sole purpose of COWpea gain storage. Rather,
households who store cowpea in a ganary also use it to store other food gains/ stuffs
including millet and sorghum. Also, because no data were available to estimate
construction/maintenance costs of a ganary, no attempt was made to assign a share of
this cost to cowpea gain storage.

Second, key estimates of the useful life of each storage technology were based on
informed opinions from Purdue University and NCRE scientists and other key
informants. Although these technologies may have some salvage value (which would
reduce the total costs of the technology), the analysis assumes a zero salvage value
because no data were available to estimate salvage value.

Third, the transportation cost of obtaining necessary inputs (e.g., plastic bags and
sheets, earthenware cannaries) from the Maroua market were not included in the cost
stream. Transport costs were set at zero because it was assumed that farmers generally
would not make a special trip to the market to purchase the inputs required for each of
the alternative technologies.

Fourth, cowpea gain was valued at the market price-«not the farmgate price--
since farmgate price data were not available.

Fifth, the opportunity cost of stored gain was set at zero in most of the analysis.
The analysis of marketing structures and the question of whether marketing margins are

high enough to cover the cost of storage were not part of the ROR section of the

166

analysis. This assumption was later relaxed in an analysis of the farmers’ "sell vs. store”
decision.
e e 3 etc t' t

The benefits to the improved storage technologies are directly related to the level
of storage losses farmers currently experience using traditional storage methods; as well
as the level of storage loss reduction associated with each alternative improved
technology. Since available data for estimating farmers’ storage loss levels were only
taken at one point in time, storage losses over time were estimated using a logistic
function. Similarly, the estimates of storage loss levels using the improved technology
are based on loss data collected at one point in time, and extrapolated over time using a
logistic function.

Several benefits assumptions were also incorporated in the model. Estimates of
household COWpea gain production, family size and their consumption rate (amount
eaten per meal) were based on data collected by Wolfson (1990). It was assumed that all
household production is pooled and household consumption is met from the pooled

production”.

 

”Each survey respondent reported key information about his/her cOWpea enterprise
and household characteristics. For large households, more than one household member
may gow cowpeas. This assumption may underestimate the total level of household
production (stock) available to a household.

167
6.2 Empirical Results: Rates of Return to Improved Storage

This analysis tested the profitability of adopting improved storage technology to
both ”traditional" and ”advanced” farmers within the context of each’s socioeconomic
situation. The reported returns under the sensitivity analysis are generally sensitive to
variations in the model parameters and differ from the base run.
W

The benefit-cost analysis for ”traditional" farmers’ adopting the improved gain
storage technologies was modeled to assess the possibility that by adopting the improved
storage technology, low-income (and low COWpCa production) households could profitably
increase their security in consumption (i.e., extend own stocks).

The analysis showed that "traditional" farmers with initial (:0pr gain
inventories of only 82 kgs/household will consume their supply of cowpea after only four
months. Consequently, they have little to gain from adopting improved storage
technologies because during the early storage period (months 1-4) bruchid populations
remain low. By the time bruchid damage is potentially severe, cOWpea household
inventories have already been exhausted.

In the base run for ”traditional” farmers, the estimated returns to the three
improved storage technologies are all negative, implying that the value of the gain
”saved” is less than the cost of investing in the new technologies. All three of the
improved technologies are dominated by (inferior to) the ”traditional” farmers’ existing

storage technology.

168

In the sensitivity analysis for ”traditional" farmers, the estimated returns to the
three improved storage technologies remained dominated by the ”traditional" farmers’
existing storage technology.

Advangd Farmers’ Situation

For "advanced" farmers, the benefit-cost analysis was modeled to evaluate the
hypothesis that by adopting the improved storage technology, high-income (and high
cowpea production) households could profitability either increase their security in
consumption or sell surplus gain on speculation.

Improved Storage for Home Consumption

The analysis showed that "advanced” farmers with initial cowpea gain inventories
of 287 kgs/household have sufficient gain to meet household consumption requirements
for approximately six and one-half months, using their current storage technology. Thus,
these farmers have much to gain from adopting the improved storage technologies
because they still hold substantial inventories during later months when bruchid
populations are potentially high and the likelihood for severe loss is geat.

For "advanced" farmers who store all of their harvest for home consumption, all
three estimated average returns to the improved technologies exceed the 50% minimum
acceptable rate of return proposed by CIMMYT (1988). Thus, they all appear to be
economically attractive for the ”advanced" farmer“. But, the MRR analysis shows that

compared to the farmers’ current storage technology (sacks), only the returns to

 

“The ARR for adopting the improved ash, triple bagging and the solar heater in
combination with triple bagging storage technologies was 177, 166 and 90%, respectively.

169

improved ash storage are very attractive”. Once the ”advanced" farmer reduces his/ her
losses by adopting the improved ash storage, the additional return to adopting the more
costly alternative is not sufficient to cover the added cost of adopting either the triple
bag or the solar heater with triple bag technology.

In the sensitivity analysis for "advanced” farmers, the average and marginal rates
of return to the improved ash technology were affected by variations in all five key
parameters of the model. The ARR and MRR to triple bagging were also sensitive to
changes in the five parameters, yet triple bagging generally remained dominated by the
improved ash technology. The solar heater with triple bagging remained dominated by
the improved ash technology.

Improved Storage for Future Sale

In the future, research is likely to increase cOWpea yields--resulting in a situation
where farmers may have available surpluses for future sale (speculation).

These ”advanced" farmers with surplus gain available for future sale may benefit
from improved storage, since experiments show high levels of bruchid damage after
several months of storage. Consequently, farmers wanting to hold gain inventories for
six or more months (until the price peaks) face potentially large storage losses.

In the base run, the benefit-cost model showed that for "advanced” farmers with
surpluses (200 kg for sale after 9 months of storage), all three improved storage
technologies generated high ARRs. Although all three technologies generated attractive

ARRs, the marginal ROR analysis demonstrated that although adoption of triple bagging

 

"The estimated MRR to improved ash storage over the ”advanced” farmers’
technology was 265%.

170
is financially promising (i.e., MRR of 124%), adoption of the solar heater (in

combination with triple bags) is not profitable because it does not generate additional
benefits above triple bagging alone.

In the sensitivity analysis for ”advanced” farmers using improved storage for
speculative purposes, the average and marginal rates of return to the improved ash
technology were affected by variations in all six key parameters of the model. The ARR
and MRR to triple bagging were also sensitive to changes in the six parameters, yet
triple bagging generally remained dominated by the improved ash technology. The solar
heater with triple bagging remained dominated by the improved ash technology.

Sen Now 9; Store and Sell Late;

Holding stocks for future sale involves risk. For example, market price increases
may not cover storage costs or the farmer’s inventory may be unexpectedly damaged-
rendering the gain unfit for sale. By selling at harvest, the farmer transfers this risk to
traders, who are generally more financially able to bear risk.

Also, by holding stocks for future sale, farmers forego the opportunity of
obtaining cash to meet immediate cash needs. Thus, they may have to borrow money
(usually at high informal market rates) to pay outstanding debts and cover immediate
household needs.

If the opportunity cost of the farmer’s stored gain is taken into account, for on-
farm storage for speculation to be profitable, the future market price received by the
farmer must geatly exceed the price at harvest. This is because in addition to covering
storage costs, the price rise must compensate the farmer for his/ her investment in stored

gain and associated risk. These analyses show that if a 3% per month opportunity cost

171

is assigied to the value of the stored gain, it is more profitable for the farmer to sell at
harvest than to store for speculation. If a 1.5% per month Opportunity cost is assigned
to the value of the stored gain, it is profitable to invest in the improved ash technology

and store for 9 months (until the market price peaks).

6.3 Limitations, Policy Implications and Research Needs
Limitations

The limitations of this study are due to the assumptions required to compensate
for the non-availability of various data. The benefit-cost analysis used a storage loss
logistic function model to estimate rates of storage losses throughout the storage
period / season. The model estimates household storage loss based on loss data collected
in March 1990 and extrapolated to project monthly future losses. The availability of
actual monthly storage loss estimates would have strengthened this analysis.

The core MRR and ARR analyses did not incorporate the opportunity cost of
stored gain into the cost stream. In the MRR analysis, only the costs that vary across
treatments are included in the cost stream, therefore the opportunity cost of stored gain
was not included. In the ARR analysis, the opportunity cost of stored gain was also not
included because the objective of the analysis was to determine the economic feasibility
of adopting improved storage technologies and did not intend to determine whether
marketing margins are high enough to cover the cost of on-farm storage. Rather, the
impact of the opportunity cost of gain was considered separate in a ”sell or store”

analysis.

172

Finally, the system-wide effect on cowpea gain prices due to lower storage losses
was not determined. Since, the cowpea market in northern Cameroon has traditionally
been thin (i.e., small share of production marketed), wide-spread adoption of improved
storage substantially reduce out seasonal price variations and thus, the returns to gain
storage, especially for speculation.

Eolig Implications

The rates of return were estimated for specific sets of investments and resulting
benefits to both "advanced” and ”traditional” cowpea farmers. The implications of these
results vary by farmer type.

Farmers classified as ”traditional" produce an average of less than 100 kg of
COWpea gain and do not follow any of the recommended improved
production /management practices (i.e., monocropping improved varieties and using 2-3
applications of insecticide). These farmers who cultivate 0.7 hectares of cowpeas,
produce primarily for home consumption. Generally, they do not incur high levels of
storage losses because their stocks are depleted before bruchid populations reach highly
damaging levels. Farmers under these circumstances would not benefit from adopting
improved storage.

Farmers classified as "advanced" produce an average of approximately 300 kg of
cOWpea gain, partly because they adopt the recommended practices (i.e., monocropping
improved varieties and using 2-3 applications of insecticide) and because they plant a
larger area to cOWpeas (mean = 1.3 hectares). "Advanced" farmers who produce
primarily for home consumption would benefit from adopting the improved ash storage,

but not triple bagging or solar heater with triple bagging. On the other hand, "advanced”

 

173

farmers who produce surpluses for future sale would benefit from adopting either the
improve ash or triple bagging storage, but not solar heater with triple bagging.

When the opportunity cost of the farmer’s stored gain is valued at 3% per
month, it is more profitable for the farmer to sell at harvest rather than store for
speculation. When the opportunity cost of the farmer’s stored gain is valued at 1.5%
per month, investment in the improved ash technology and storing until the market price
peaks (historically in August) is profitable.

mm

A farmer’s storage decisions depend on his/her overall household food security
strategy. The strategy a household adopts will depend on numerous factors including
resources available to the farmer (i.e., land, labor, and/ or capital), access to marketing
and price information, household consumption needs, credit availability, and non-farm
employment opportunities. Clearly, the farmer’s decision / strategy is based on an
interaction among these factors and not one factor alone. Furthermore, recognizing the
differences among farmers’ circumstances, desires and needs accurate and representative
farm-level data are needed to help researchers and extension agents assess a technology’s
potential and constraints faced by farmers in making their technology choice decisions;
as well as setting research priorities within a broader socioeconomic framework.

Research designed to address farmers’ storage needs must be based on a clear
understanding of how farmers allocate their production between consumption, storage,
sales and other uses/disposal. In addition, understanding farmers’ marketing patterns,
the basic market infrastructure and market information is imperative so as to inform

researchers/scientists about the potential demand for improved on-farm and / or off-farm

174

storage. The following list is provided as a guide for project managers and researchers
as to the minimum data needed to assess the socioeconomic feasibility of gain storage
technology.

Total Availability of Cowpea Grain

0 Data are needed to estimate total household cowpea availability, including the
amount of gain supplied by all household members, from all fields managed by the
household. In addition, plot level data on the gender of the plot manager is needed to
determine who makes input and management decisions and who controls the production
(in terms of its use for home consumption and/or sales). These data are required to
generate a better understanding of the roll of cowpeas in the farming system.
Household Consumption and Utilization

0 Accurate estimates of household consumption data (kg actually
consumed/household/week and seasonal variations in consumption) are needed to
calculate the rate at which gain is drawn-down; and to determine the contribution of
cowpeas to household nutrition.

Storage Losses Over Time

0 Accurate estimates of the current level of farmers’ losses is critical to evaluating
the potential of improved storage technologies. Data should be collected to assess the
monthly storage losses associated with each alternative storage technology by sampling
each month gain stored by farmers using each of the storage methods“--including

gain stored for home consumption vs gain stored for sale, etc.

 

“Including both the traditional and irnproved/ new storage technologies.

175
Sales Pattern

0 Household sales (commercialization) while, little is known about households’
current selling behavior, whether the crop is gown for home use or sale will geatly
affect the household’s willingiess to adopt new technology. Data are needed to
determine when cowpeas are sold, the amount sold (kg of gain /leaves/pods), to whom
(local market by farmer, middleman), the price received (farm gate vs. market), and how
the farmer is paid (cash, in-kind). For example, Wolfson observed that if men control
commercialization, it is usually sold in large (50 kg) lots, but if women control
commercialization, it is usually sold in small allotments. A better understanding of these
issues is relevant in determining a technology’s potential. For example, if the gain
storage needs of women are to be met--and they sell in small lots over the seasonuthen
triple bagging may not be appropriate for them because its effectiveness if decreased by
repeatedly opening and closing the plastic bags.
Input and Output Prices
0 Accurate input and output prices are critical to estimating the benefits and costs
of an improved technology. Because prices vary across space and over time, data must
be collected on prices farmers actually pay for inputs and the prices they actually receive
for their crop (farmgate price).
Off-Faun Storage

The Cameroon research has focused on reducing on-farmers storage losses. But
participants further along the marketing channel (i.e., middlemen, traders) may benefit
even more than farmers from adopting improved storage technology if, as it appears to

be the case, most of the cowpea crop is sold at harvest and stored for speculation by

 

176

these market intermediaries. Data are needed to determine where in the marketing
system the storage function is being performed-including the middleman’s share of total
storage, gain stock turnover, storage losses, and methods practiced to reduce loss. This
information could by obtained by a market survey/ study. Potentially, the improved gain
storage technologies developed by the Bean/Cowpea CRSP scientists may geatly benefit
off-farm storage users (i.e., middlemen and traders) and ultimately consumers. Because
they likely store large volumes of gain for extended periods, the potential for loss is
geat. Under such circumstanced improved ash storage is not feasible but both the triple
bag and solar heater are likely to be an economically viable storage investment.

Overall these results indicate the profitability of the improved storage
technologies will depend on the level of losses farmers currently incur, the level of
protection provided by the new technologies, the cost of adopting the improved
technologies and the market price.

In designing their overall research strategy, the Bean / Cowpea CRSP scientists
have sought to both design improved storage technologies and introduce bruchid
resistances into new varieties. While the improved technologies are likely to only benefit
a small share of the cowpea producers, the development of improved bruchid resistant
varieties will have a much wider impact. Once introduced, bruchid resistant varieties will
reduce losses-regardless of the farmers’ current storage technology. Furthermore, all
cowpea farmers will benefit from this technology, at no additional cost other than
purchasing the resistant seed. In addition, the introduction of bruchid resistance will

continue to provide protection against bruchid losses once cowpeas are marketed. In the

177

long run, reduced losses will benefit consumers as these gains are translated into lower

retail cowpea prices.

178

Table A1 Sensitivity Analysis: "Traditional" Farmer Using Improved COWpea Storage
Technologies for Grain Intended for Home Consumption'; Run 1,
Household Losses + /- 50%.

-: Pm’Cuneu Wm WEB-38mm" SolarHeaterlTrble:
1 Practice” Stonge‘ BagStonge‘

F..- - - g- — .. _ __.7. -7 ,, 7 y -7 We A g. g- .. Lafif .4

‘ b‘+50% b.5095 bums 5.5095 mm mm b+m b.5095

' " ’i’l

  

  

 

 

Costs (CFA)

Addition-l Net Benefits NA
Add'uional Annual Costs NA
late of Returns (%)

Average NA
Mirth-l NA

 

 

‘akgdwwpugainuondundernon-adopterhmerm

°2cnnnnries.

“Gin-ticket

‘lsollrhedershlredbymhomeholtbplusépluficbap.

“6' represenubuemvaluestorthenrhble.

quofmm-smflofmmwmm
mag) 'saved'valuedstmonth5(March)mutetpriceof113CFA/kg

. opportunitycostofcaphl (3% permuth) (or! 1:0th (November-Much).

’I‘otalcosts/mefullifeofthetechuolog.

179

Table A2 Sensitivity Analysis: ”Traditional" Farmer Using Improved COWpea Storage
Technologies for Grain Intended for Home Consumption'; Run 2, Improved
TechnologyI Losses + /- 50%.

Pm’Currell Wm “1....ng Sauna-ceramic
W W mating

i __. __ ,, 7 a 7, W .7 .__ . _. —. —. g‘ ._7. __ 4

sum b-5095 “5095 um um _bjsoes “50% hm

b——.~ 7 , ~- ,, 7 —7 , 7 — __,__ ——-—-—- 1

 

 

Grab w (u) o o 3.46 524 5.62 651 5.62 6.51
w lulu-t (CFA)
Gross Benefits" 0 o 391 592 635 736 635 736
Total Comi o o 3.473 3,478 1,043 1,043 1.901 1,901
Annual Costsi o o 696 696 1.043 1,043 1.472 1,472
Net Beacon NA NA .305 -104 .408 .307 -837 ~736
(gross benefls mints _
1
Costs (GA)
I
Addition: Net Benefls NA NA 0 o o o o o f
Addition-t Annual Costs NA NA 696 696 347 347 429 429 i
m or let-u (1,) i
1
Average NA NA 433 14 9 -39 1 .29 4 56 9 .50 o i
Marginal NA NA D D D D D D
unawmmmmmmam
t’(iI-umy.
°2 cannaries.
‘6 plastic

Wmudmpagfinuamulofmmww
Wmm) "slved valuddmonthSNuch)mrtetpdceof113CFA/kg.

'Induduoppmtunhymdolaphl(3%permodh)lor5mntll(November-Much).
’Totdcods/metulli‘eoflhetedmolog.

 

180

Table A3 Sensitivity Analysis: "I'raditional'I Farmer Using Improved COWpea Storage
Technologies for Grain Intended for Home Consumption‘; Run 3, Input Cost
+ /- 25%.

rm'om WM WNW“ somneuerampte

1 bt+25% b-25% b+25$ b-fi‘lb b+25% b-25% b+25% b-25%

‘4

 

; Grab Smut (m o o 4.4 4.4 6.1 6.1 6.1 6.1
[ mm W (CFA)
1 Gross Renew“ a o 497 497 689 689 689 689
Q Total Costsi o 0 4,347 2,608 1.304 733 2,377 1,436
’ Annual Costsl o o 869 522 1,304 783 1,340 1,104
Net Benefits NA NA .372 .25 .615 .94 4.151 .415
\ (you benefits minus
1 annual costs)
Magi-n1 Benefits and
Costs (CFA)
Addhronnl Net Benefits NA NA 0 o o o o o
Addhionnl Annual Costs NA NA 869 522 415 261 536 321

 

'lsolnrhentershuedbymhomeholtkpltIGplnsficbnp.
“b'representsbuerunvnluestorthevnrinble.
3Addltionnlkgotcowpeegninnsaresultofmhgthelnprwedtechnologes.
Wmmrmwwmumsm)mmormcrwu
'lndudesoppomlnitycostofaplnl (3%per1nouh)tor51nomh(Navember-Mareh).
trauma/manufactmucnnobg.

181

Table A4 Sensitivity Analysis: ”Traditional" Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Home Consumption‘; Run 4, Market
Price of Cowpea Grain +/- 25%.

WMW‘ Sauna-mam»:
,_ _MW°

, bum. b.2596 b+25% b-3% M395 b-25% b+25% mm;

 

 

mnofwwpugahnondundamnadopterhmrm
t’Grnnnry.

‘2cnnnaries.

“Mb-1st

‘lsolnrhentershnredbymhomeholfiphl6plsucbnp.
“b-npuuemmmnmutonnem
'Additionnlkgofcowpengninusresulofmingthehmmdtechnologies.
Wanin(kg)'med'vdueddmonth5(M)mpdoeof113CFA/kg
flndudaopportunhywdofaphl(3%permonth)tor5mntb(Nwenber-Mnrch).
’l‘otnlcosts/ueftfllfleottheteehnolog.

182

Table A5 Sensitivity Analysis: "Traditional" Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Home Consumption'; Run 5,
Opportunity Cost of Capital/Interest Rate + /- 50%.

 

 

 

Fm'clnm WM maggot-'6‘ Sound-mam
W

 

 

bum b.5096 tum 6.5096 mm 630% b+5096

 

Grab 8.“ (kg) 0 0 4.4 4.4 6.1 6.1 6.1

 

Gross Benefits" 0 o 497 497 689 689 689
Total Coatsi o o 3.739 3,232 1.122 970 2,044
Annual Con-i o 0 743 646 1,122 970 1,583
Net Benefits NA NA -251 .149 443 -231 .394
(gun benefits minus

annual costs)

Marginal Benefits and

Coats (crA)

Addmonnl Net Benefls NA NA 0 o o o 0
Additional Annual Costs NA NA 746 646 374 324 461

 

Rate of Returns (‘5)
Average NA NA -33.6 -23.1 39.5 -29.0 ~56.5
Marginal NA NA D D D D D

:5

kgofcowmgainatoredmdernon-adoptafamerMn.

i

cannaries.

°2
d6
‘laolarheatershaledbymhouehokkplmépI-flcbag.
‘1»- representsbuerunvaluesforthevariable.
‘Additionalkgotcowpeagainasamultofmtngmuvedteehnobgies.
“Coupupamm "aaved valuedatmonthSMmhhnarketpflceofllBCFA/kg
‘Indudaopponunitycostofcapial(3%permouh)br5m(NmberhMamh)
’fotdcost/uethllfleofthetedlnolog.

 

183

Table A6 Sensitivity Analysis: “Advanced” Farmer Using Improved COWpea Storage
Technologies for Grain Intended for Home Consumption‘; Run 1,
Household Losses + /- 50%.

 

 

whammmmmmmm
ӎddhsach.

‘6cannaries.

“1813mm

‘laohrhedersharedbymhomhokbplmlsplflichap.
"b'npreaentabaaemnvaluesfortbevariable.
‘Addiionalkgofoowpeagainuaresultohlingthehpmvedtechnobglea.
h(taupe-glnlullg)unwed-valued«mourn(May)ulnrlmprleeotl17CFA
. gain(kg) 'saved'valuedatmonth8(1une)martetprlceofl7l CFA.
’Indudesopportunityoostotcapltal(3%perlnodh)tor7lnonths.
"lndndaopponunllyeodorapw(396pemonul)lorsmom
’I‘otalcosts/uefullifeofthetechnolog.

184

Table A7 Sensitivity Analysis: "Advanced“ Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Home Consumption‘; Run 2, Improved
Technology Losses + /- 50%.

‘ Fm'onml WM WEB-3W6 Sownenlcra'mple
R- W m“ mm‘

 

   

___ . ._ . __ ___.__. ___.__.--. _ . . . ___» ____————————————4

, 6‘45096 6-5096 645096 6.5096 mm 6.30% b+5096 6.5096

g, , 7777 #—_—r._ _. ___—..———7—— _ _{

  

  
     

 

‘287kgofcowpeagalnstoredunderadvancedadopterlarmersttuation.
béclothaacks.

‘6cannaries.

dprlastlcbap.

‘lsolarheateraharedbymhomeholdsplusmpmu’.

‘1:- npreaentabaserunvaluesforthevarlable.
Mmmnofcowpeagainuaruulofmingtheumrwedtechnologia.
Wmmrmed-muedumnm7m-y)mmotu7crA
flnduduoppmtunitycouothifl(3%permonth)for7montb(Nmber-May).
’Totflcnds/uehtllileofthetedlnolog.

185

Table A8 Sensitivity Analysis: "Advanced“ Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Home Consumption‘; Run 3, Input Cost

 

 

 

 

 

 

 

 

 

 

+ /- 25%. ’
Grab w (kg)
W W (CFA)
Gross Benefits" 0 0 6,131 6,131 7,172 7,172 7,172 7,172
Total Costsi 2,767 1,660 13,836 8,302 4,151 2,490 15,527 3,173
Annual Cod-i 922 553 2.767 1,660 4,151 2,490 9.339 2,832
Net Bench NA NA 3,364 4,471 3,021 4,682 -2,667 4,340
(gross benefits minus
annual costs)
W Ma and
Costa (CFA)
Additional Net Benefits NA NA 3,364 4,471 0 211 0 0
Additional Annual Costs NA NA 1,845 1,107 1,384 830 5,688 342
Rate of Reta-as (‘5)
Average NA NA 122 269 73 188 -27 153
Margnal NA NA 132 404 D 25 D o
'287kgofcowpeagalnstoredunderadvancedadopterfarmersltuatlon.
I’6 cloth sacks.
c6 annarles.
‘16 plastic bags

‘lsolarhedersharedbymbomebolthplm 18phsticbap.

“b' representabaaerunvalueslortbevariable.
‘Add'uionalkgofcowpeagalnuamultofmingtbelnprovedtecbnobgia.
Wgain(kg)'saved'valuedatmontb7(May)mnrketplice01117CFA.
flodudaoppmflnnhyoostolcapital (3% permontb) for? months (November-May).
’l‘otalcosts/lnefullifeoflbetecbnolog.

186

Table A9 Sensitivity Analysis: ”Advanced" Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Home Consumption‘; Run 4 Market
Price of Cowpea Grain + /- 25%.

 

 

 

 

 

 

 

 

 

 

Pm'omnt WM TrbleBagStonge‘ Solarlleataranlple
Practice" W Bag Storage‘
— j
ohms b-ZS‘ll b+25% 6.2596 b+25% 6.396 b42596 b-25%
_
onla sand! (w 0 0 52.4 52.4 613 61.3 61.3 61.3
Patti-I locust (CFA)
Gross Benefls" 0 0 7,664 4,596 8,965 5,379 8,965 5,379
J Total Coatsi 2,214 2,214 11,069 11,069 3,321 3,321 4,231 4,231
Annual Canal 733 736 2,214 2.214 3,321 3,321 3,776 3,776
Net Benefits NA NA 5.450 2,334 5.644 2,058 5,189 1,603
(go-s benefls minus
annual costs)
W Benefits and
Costs (CFA)
Additional Net Benefits NA NA 5,450 2,334 194 0 0 0
Additional Annual Costs NA NA 1,476 1,476 1,107 1,107 455 455
Rate of Int.» (%)
Average NA NA 246 108 170
Marginal NA NA 369 162 16 D D D
‘
:u7kgofcowpeagainstoredunderadvancedadopterfarmersituation.
I’6 cloth sacks.
‘6 cannaries.
‘13 plastic bag.

‘lsolarbeatersbaredbymhomebokkplmlsplasticbag.

“b' representsbasenmvaluesfortbevariable.

‘Additionalkgofcowpeagainasaresuhotulngtbehwrwedtecbnologes.
gain(kg) "'saved valuedatmontll7(Mly)marketprbeof117CFA.

‘lndudaopporumlycodofapld(3%permonth)tor7montln(NovembehMay).
’I‘otalcosts/lnefullifeoftbetecbnolog.

 

187

Table A10 Sensitivity Analysis: “Advanced" Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Home Consumption'; Run 5
Opportunity Cost of Capital/ Interest Rate + /- 50%.

 

 

 

 

 

 

Farmers' cine-t W Aall 'nlpla Bag Storage‘ Solar Heater a Triple
W Storage‘ Bag Storage
3'42596 b.5096 64296 3.5096 b+50% b.5096 b+50% 3.50%;
out. Sandi (to 0 0 52.4 524 613 613 613 613
Partial lodge! (CFA)
Gm Beacon“ 0 0 6,131 6,131 7,172 7.172 7,172 7,172
Total cm‘ 2.450 1,993 12,243 9,939 3,674 2,997 4,631 3,313
Annual Costsl 317 666 2.450 1,993 3,674 2,997 4,173 3,407
Net Banana NA NA 3,631 4,133 3,493 4,175 2.994 3,765
(go. benefls mints
annual costs)
Hulk-l sauna and
Costs (cm
Additional Na Benefits NA NA 3,631 4,133 0 42 0 0
Additional Annual Costs NA NA 1.633 1,332 1,224 999 504 410
late of let-1s (%)
Average NA NA 150 207 952 139 72 111
Marginal NA NA 225 310 o 42 o D

 

 

Wigotoaupeagainstoredunderadvancedadoptertarmermion.

b6dotnaacsa

‘Gcannaries.

‘18plasticbag.

'lsolarhedersharedbylomplumpldicbag.

I'19-representation:mnvaltmlortaevarlalila

IAddfiionalkgofoawpeagainasaresuloflsingtheinqirovedtechnologles.
9mm) "saved valuedatmouh7(May)martetprlceotll7CFA.

'lnduduoppmumhycouofcqlal(3%permouh)tor7m(November-May).

’l‘otalcosts/uefullileolthetechnolog.

 

188

Table A11 Sensitivity Analysis: “Advanced“ Farmer Using Improved Conea Storage
Technologies for Grain Intended for Home Consumption‘; Run 6, Solar
Heater with Triple Bag Technology 100% Protection.

WM TrbleBagStorap‘ Selene-mam
W MW

52.4 61.3 795

 

 

7,172

 

:287kgotoowpeagainstoredunderadvanoedadopterfarmershuation.
bédothaach.

cStiallrlal'llis.

“lam-mew

claolarbedersllamdbylllllousellolcbplm ”planking.

"b Wmsbasemnvaluesbrtbevariable.
kagolmpagainuaresuhofmingthewwebnologes.
“Cowpeagamm saved'valuedatmomh7(May)maltetprlceolll7CFA.
’lndudaopporflnltyaxtoteapld(3%permonth)tor7months(Nmmber-May).
’l‘otaloosts/llefullileofthetedlnolog.

189

Table A12 Sensitivity Analysis: “Advanced” Farmer Using Improved COWpea Storage
Technologies for Grain Intended for Future Sale‘; Run 1, Household Losses + /-
50%.

 

 

 

 

 

Total Comi 1,613 1,613 8,063 8,063 2.419 2,419 3,414 3,414
Amml Cami 538 533 1,613 1.613 2,419 2,419 2.916 2,916
Net Beneflta .509 266 33,941 33,157 34,939 34,155 34,442 33,658
(you benefit minus
annual costs)

r W M: and
Coats (CFA)
Additional Net Benefits NA NA 34,450 32391 998 993 497 .491
Andaman Annual Coda NA NA 1.075 1,075 806 806 497 497
m or luau (1:)
Average -95 49 2.104 2,056 1,444 1,412 1.131 1,154
Marginal NA NA 3.205 3.060 124 124 o D

Ir

‘200 kg of cowpea grain stored under advanced adopter farmer station.

”4 cloth acts.

‘4 annariea.

‘12 PW baa

‘laolarbederaharedbymbomeboldaplmnplasflchap.
“b'repreaentabaaerunvaluestortbevarlable.
lAdditionalkgotcowpeagninaareaunotmlngtbeWtechnobgiea.

grain(kg) 'aaved‘valuedatmomh10(Augmt)marketprlceofl96CFA/kg
iIncludeaoppomlniycoatofeaphal(3%permontb)[orlOmontII(November-August).
’fdfloofl/mefullifeoflbetechnolog.

 

190

Table A13 Sensitivity Analysis: ”Advanced" Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Future Sale‘; Run 2, Improved
Technology Losses + /- 50%.

__.. . , ._7, ,__*‘

Farmen’Curled Wm magnum" SolarHeaterkTrble

 

9 Grab Sandi (Ira) 0.6 0.6 111.5 134.2 136.1 1913 136.1 1913

 

 

 

 

Putin] asap: (CFA)
Gm Beacon" 113 113 34.790 36,103 36,593 37,593 36,593 37,593
Total clami 1,613 1,613 3,063 3,063 2,419 2,419 3,414 3.414
Annual Use Cami 533 533 1.613 1,613 2.419 2,419 2.916 2,916
Net Banana 420 420 33.177 34,490 34.174 35.174 33,617 34,617
(gro- benefita minus
annual coats)
Mal-glad Ma and
Coats (CFA)
Addiuonal Net Beacon NA NA 33.597 34.910 997 634 497 497
Addiional Annual Coats NA NA 1,075 1,075 306 306 491 497
late of lat-Ia (‘5)
Average -78 -78 2,057 2,138 1,413 1.64 1.155 1,189
Marginal NA NA 3.125 3,247 124 35 o o
1 E ~——— — —‘
‘200 kg at cowpea grain stored under advanced adopter farmer situation.
”4 doth acts.
‘4 cannaries.
‘12 plastic bag.

‘laolarbeaterabaredbymboueholaplmupl-tlcbap.

“1:- repmcnlabaaemnvaluea [ortbevariable
‘Addhionalkgofcowpeagninaaaruulohflngtbelnpravedtechnobdu.

. grain(kg) 'aaved' valuedatmoalh10(Augllt)marketprloeofl96 CFA/kg.
{Includes opponun'ly coat of eaplal (3% per month) for 10 month (November-Angst).
’I‘otalooats/uetulliteoftbetecbnolog.

191

Table A14 Sensitivity Analysis: ”Advanced“ Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Future Sale‘; Run 3, Input Cost + /-

 

 

 

 

 

 

 

 

 

 

25%.
Pm'onlenl WM WhBagStorage" Solarllealera'rrlple
Practice" Stomp" Bag Storagec ‘
o‘+2596 b-25% 342596 3-2596 194-3% b-25% b+25% b.2596,
_ 1,, — ~ 7— 4
Grain Small (1;) 0.6 0.6 130.9 130.9 190.1 190.1 190.1 190.1
Partial loop: (CFA)
Groaa Benefits“ 113 113 35.456 35.456 37,260 37260 37,260 37,260
Total Coal:i 2,016 1,210 10,079 6,043 3,024 1,314 4267 2,560
Annual Cami 652 403 2,016 1,210 3.024 1,314 3,645 2,137
Net Beacon .534 .235 33,440 34,246 34236 35,446 33,615 35,073
(groaa benefits minus
annual costs)
Marginal Benefits and
Costa (CPA)
Additional Net Benefits NA NA 33,974 34,531 796 1,200 -621 -373 l
1
Aoaalonal Annual Com NA NA 1.364 307 1003 604 621 373
late or Returns (76)
1
Average .32 -71 1,659 2,330 1,132 1,954 922 1,604 ;
Marginal NA NA 2.491 4,279 79 199 o o ‘
'200kgofoowpeayain3toredunderadvancedadoptertarmerahuation.
t’4 oloul aaoka
‘4 cannaries.
‘12 plastic bag

e1solarllealenllanecloylollouaellolnsplualzplaallellaga
"b'repreaentabuerunvaluea forthevariable.
‘Addiionalkgofcawpeagninmamulotmingtheimpruvedtechnobgiea.
“Co-meaning) 'uved'valuedatmonth 10 (August)marletpdeeotl96 CFA/kg.
flnolunea oppomlly coal oroapllal (396 per month) tor 10 montll (November-August).
"l‘otalooata/Ilefullifeoltbetecbnolog.

 

192

Table A15 Sensitivity Analysis: “Advanced" Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Future Sale‘; Run 4 Market Price of
Cowpea Grain +/- 25%.

 

6‘+2596 b-2596 o+2596 b-25% b+25% b-B% b42696
_

0.6 0.6 1N3 180.9 1!“ 190.1 190.1

 

 

W W (CFA)

Grout Benefitth

Total Coal:i
Annual Coat-i
Net Benellu

(great benefit minus
annual coats)

 

'200kgofcowpeayninttoredunderadvancedndoptertarmertluation.
”4mm

‘4annariea.

“Homage

e1solarluaalaualaandlly1011ouaellolllaplualzplaatlcllaga

‘11- repretenttbatemnvaluettorthevariable.
Mionalkgofoowpeagrainatatetultohnlngtheinmwvedtechnobdu.
"Cottpeagrain(kg)'taved'valuedumomh10(Augutt)marIetptloeot196CFA/ig
lindudaoppmflmhyeodotapifl(3%permoflh)brlOmontht(Navember-Augmt).
’l‘otalcoett/utehtlllleotthetecbnolog.

193

Table A16 Sensitivity Analysis: “Advanced” Farmer Using Improved Con/pea Storage
Technologies for Grain Intended for Future Sale'; Run 5 Opportunity Cost
of Capital/Interest Rate + /- 50%.

 

 

    

        

b-m b+50$ b-50% 134-50%

—
Gl'lh w M 0.6 0.6 1&3 180.9 I”. l IWJ. INJ

b-50%

 

l-astlal Isd'et (CFA)

 

 

 

Gross Benefitsh 113 113 35,456 35,456 37.260 37.260 37,260
I Total Costai 1.364 1,393 9,313 6,963 2,795 2,039 3,945
Annual Coed 621 464 1,364 1,393 2,795 2039 3,370
Net Benefits -503 -346 33,592 34,063 34,465 35,171 33,390
(gross benefits mints
annual costs)
Marginal Benefits and
Costs (GPA)
Additional Net Benenta NA NA 34,095 34,409 373 1,103 .573
Additional Annual Costs NA NA 1,243 929 931 696 575
late or Rat-nu (%)
Average -31 -75 1,302 2,445 1,233 1,634 1,006
Marginal NA NA 2,743 3,704 94 159 D
=—
Wuotwupeay'ainttomdunderadvanoedadoptertarmertiuation.
I’4 cloth sacks.
‘4 cannaries.
‘12 plastlo boat

‘1solasheatesslsaaedbylohotuelsoldaplu12plastlcbap.
“b-sepsesentsosuemnvaluesrostaevuiable
‘Addhionalkgotoovpeagainmaresultohsingtbeinpmvedteehnobgiet.
Pompea gain (kg) 'taved' valued stnsontll 10 (Augutt) marketprloeot 196 CFA/kg,
'Includesopportunhyoostoteq'sal (3% permonth) for 10 montls (November-August).
trotal onsta/usetul lireortlse technology.

194

Table A17 Sensitivity Analysis: ”Advanced“ Farmer Using Improved Cowpea Storage
Technologies for Grain Intended for Future Sale‘; Run 6, Solar Heater with
Triple Bag Technology 100% Protection.

 

 

 

 

 

 

 

 

 

 

Fm'ctment lapsovadAali 'mpleaagsmsane‘ SolasHeatesaniple
W Storage‘ Bag Stotap‘
oral- Sand (kg) 0.6 130.9 190.1 200
natal todast' (CFA)
Gross oedema! 113 35,456 37,260 39,200
Total Costs" 1,613 3,063 2,419 3,414
b Annual Costai 533 1,613 2,419 2,916
Net Benenn -420 33,343 34,341 36,234
(you benefit mints
annual costs)
Magi-a1 Benefits and
Costs (CFA)
Additional Net Beneat- NA 34,263 993 1,326
Additional Annual Coats NA 1,075 306 «7
Into of lat-It (‘5)
Average ~78 2.096 1.440 1.244
Marginal NA 3,137 124 267
—
WigotcowpeayainstoredunderadvanoedadoptertarmeIMn.
”4 cloth tanks
‘4 cannaries.
‘12 plastic bags

e1solastseatessltaiedtlvy1ottonaelsoldapluslzistastlctiaga
‘Addhionalkgoloawpeagninmaresulottsingtheinpmvedtechnologiet.
'Covpeapain(@‘tned'nlueddMlOMquOmartetpdoeovaCFA/u
_‘lndudaoppmtunkycodotapld(3%permoflb)torlflmodb(Nwember—Augtst).
’l‘otalootts/tsetulliieottbetechnolog.

 

195

Table A18 Sensitivity Analysis: ”Advanced“ Farmer Using Improved COWpea Storage
Technologies for Grain Intended for Future Sale‘; Run 7, 20% Premium
Paid for Improved Quality Grain.

larprovedAsll TrbleBagStoraged SolarHeatertTrble
W

3.3 Stu-32‘

oral- Savad' (kg) 0.6 130.9 190.1 190.1

 

 

 

 

Partial soda-t (GA)

 

 

 

Gross neneotal 113 42,543" 44,712h 44.712l|
Total Costai 1,613 3,063 2,419 3,414
Annual Costai 533 1,613 2,419 2.916
I Net Benefit 420 40.935 42,293 41,796
(gross benefit mints
annual costs)
W Ma and
Costs (CFA)
Addhionll Net Benefit NA 41.355 1,358 497
Addlional Annual Costs NA 1,075 806 497
‘ late (I m (%)
Averap -78 2.538 1,748 1,433
Marginal NA 3.347 168 D
‘200 kg at cowpea grain stored under advanced adopter {armer thuation.
I’4 cloth sacks.
‘4 cannaries.
‘12 plastic bag.

‘1tolarbeatertbaredby10b01sebokltplts12platticbap.
'Addhionalkgofcowpeayainmamuloftsingtbeiwmvedtecbnologies.
lCowpeagrainflg) "taved valuedatmontb10(AugIst)marketpticeofl96CFA/kg

grain(kg) "saved valueduMptemiummomb10(Augtst)muketpriceot2352CFA/kg
lndudaoppoflunhymdotapflfl(3%permonth)tor10mo¢ls(November-Augtst)
’l‘otalcosts/tsefullifeoftbetechnology.

 

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