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Assessing the Potential for Vegetative Cover in
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A Case Study from the Dominican Republic

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Charlotte Gaye Burpee

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ASSESSING THE POTENTIAL FOR VEGETATIVE COVER
IN HARSH. TROPICAL ENVIRONMENTS:
A CASE STUDY FROM THE DOMINICAN REPUBLIC

BY

Charlotte Gaye Burpee

A DISSERTATION

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

DOCTOR OF PHILOSOPHY

Department of Crop and Soil Sciences

1995

ABSTRACT
ASSESSING THE POTENTIAL FOR VEGETATIVE COVER
IN HARSH. TROPICAL ENVIRONMENTS:
A CASE STUDY FROM THE DOMINICAN REPUBLIC
BY

Charlotte Gaye Burpee

Vegetative cover is a key to protecting soil from degradation, but is not used
extensively in tropical agricultural systems, due in part to socio—economic and
technical constraints. This research addressed physiological (weather and soil),
ecological and socio-economic constraints to the use of vegetative cover for food
production and erosion control in a rural village in the tropics. Specifically, there
were four phases: 1) characterizing boundary conditions of temperature and water
for germination of eight tropical species and two temperate benchmark species in
growth chambers, 2) evaluating reliability of laboratory germination tests as a rapid
screening technique for soil surface germination at a semi-arid field site, 3)
investigating sociO-economic factors with potential to affect dry-season cover crop
adoption and use and 4) reviewing patterns of land use and marine ecosystem
change and their relationship to human activity systems to address possible
constraints and advantages to the use of vegetative cover.

Boundary condition experiments clearly identified species with potential for
harsh surface soil environments like those found in the village of Buen Hombre
(vegetable amaranth, jack bean, tropical kudzu, lablab bean, sunnhemp, tepary
bean, and tropical velvet bean). Two species, vegetable amaranth and tepary bean,
germinated well under a wide range Of temperatures and water potentials, and
sunnhemp performed well at all but the driest water potentials. Jack bean, Iablab

bean and tropical velvet bean were only able to germinate within a narrow window

of near-saturation water potentials, but tolerated a wide range of temperatures.

Field germination was reduced 19 to 44% compared to lab germination and
was severely limited by biological interference from birds and insects. Biotic factors
were equally or more important to germination success and early survival than soil
or weather factors.

In combination with key informant and group interviews, traditional socio-
economic survey instruments yielded valuable data. Villagers barely subsist in a
non-cash farming-fishing economy, which is based on intricately related, fragile
marine and terrestrial ecosystems. Vegetative cover, if introduced at no cost to
farmers and evaluated in collaboration with them, has great potential to diversify
agricultural production activities, extend the growing season and protect marine

ecosystems from potentially damaging erosion.

To my husband and children,
John A. Siebs, Jr., Cameron Burpee Siebs and Alexis Burpee Siebs;
to my mother and father,

Charlotte Bates Burpee and W. Atlee Burpee Ill;

and to the people of Buen Hombre.

 

ACKNOWLEDGEMENTS

I am indebted to my official committee members, above all for friendship and
scientific mentoring -- to Dr. Francis J. Pierce for unusual commitment from a major
professor in time, creative input, lab support and exceptionally high scientific
standards; to Dr. Kenneth L. Poff for unusual commitment from a committee
member in intellectual stimulation, moral support and the Opportunity to collaborate
in the design and teaching of an innovative course; to Dr. Rich Stoffle for collegial
acknowledgment since 1985 at the lnstitute for Social Research, for collaborative
Opportunities in the Dominican Republic and for understanding the obstacles of
conducting research in a remote village; to Dr. Jim Crum for advice and literature on
tropical soil management; and to Dr. Richard R. Harwood for support through a Mott
Sustainable Agriculture Fellowship and for providing the opportunity to attend a
Farming Systems Research and Extension Symposium.

I am also indebted to my unofficial committee member, Dr. Stuart Gage, for
introductions to systems methodology for biological systems and to remote sensing
technology, for access to expertise and equipment in his Spatial Analysis Laboratory
and for support in the difficult process Of combining disciplines in systems research.
In addition, I owe thanks to Mr. Luc St.-Pierre of the Centre d’Applications et de
Recherches en Télédétection, Canada, for sharing methodology and remote sensing
data; to Dr. Phil Robertson for advice on ecological aspects of proposals, research
and reports; to Mr. Amos Ziegler for assistance with computer cartography; to Dr.
Roland Fischer for training in applied entomology and for Offering to classify tropical

specimens before his death; to Dr. John Beaman for training in botanical techniques

of plant collecting; to Dr. Tom Wagner and Dr. Ray Laurin at ERIM for sharing
remote-sensing and land use data; to Dr. Tom Williams at the Michigan Department
of Public Health for providing expertise and water analyses free of charge; to Dr.
Dale Harpstead and MUCIA for an internship in Costa Rica; to Dr. Thomas Zanoni of
the National Botanical Gardens, Dominican Republic (D.R.), for identification of plant
specimens; to Mr. Tomas Montilla of DIRENA, D.R., for field research assistance; to
Rector Benito Ferreires and Professor Yocasto Soto at ISA, D.R., for an office and
field plot space; to lngeniero Rafael and Senora Aida Serulle Of Santiago for
friendship, transportation, lodging and logistic support; to Dr. Jose Serulle and Dr.
Jacqueline Boin of the Science and Art Foundation of Santo Domingo for publicity
about the natural resource situation in Buen Hombre; to Lic. Ivonne Garcia,
subdirector of the National Forest Commission, D.R., Maria Eugenia Recio, Director
Of the Office of Technical Coordination, Marina Tejera, Director of Fisheries and
Cecilio Valdez, subsecretary of the Ministry of Natural Resources, D.R., for meeting
with villagers and dealing effectively with degradation of natural resources in Buen
Hombre; to Pedro Canela and Tuba Perez for field plot space and expertise; to Genio
Burgo for a water burro; to Ramon Cabrera and Apolinar Burgos, presidents of the
Farmer's Association, for advice and expertise; to Narciso Gomez, president of the
Fisherman's Association for labor and expertise; to Tuba Perez and Carmen Perez
for lodging, wisdom and friendship and finally to the children of Buen Hombre for
collecting insect specimens, especially their proudest contribution, a seven-inch
tarantula.

I am most grateful for funding that permitted me to complete doctoral

research and coursework:

O a National Science Foundation doctoral dissertation grant (BSR-901
6597)

O a C. S. Mott Foundation Doctoral Fellowship in Sustainable Agriculture,
0 a Doctoral Dissertation Completion Fellowship from the Graduate School,
Michigan State University,

0 a private grant from Orris Bell Lewis

0 and funding for equipment from the Office of Research and Graduate

Studies, Michigan State University.

vii

TABLE OF CONTENTS

LIST OF TABLES
LIST OF FIGURES
INTRODUCTION

List of References

CHAPTER 1. Boundary conditions of germination for eight species
Of vegetative cover with potential for the tropics

Introduction
Overview of Seed Germination
Seed dormancy
Germination and water uptake
Germination and temperature
Germination and light
Temperature-water-light interactions and germination
Laboratory data as a predictor of field germination
Materials and Methods
Species selection
Germination test procedures
Temperature experiments
Water potential experiments
Pre-treatment experiment
Substrate experiment
Dormancy-breaking experiment
Use Of thermal time
Statistical design and analyses
Results and Discussion
Temperature and water potential experiments:
benchmark species
Temperature and water potential experiments:
eight tropical species
Seed moisture percent at germination
Pro-treatment experiment
Substrate experiment
Conclusion

viii

xi

xiii

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OO‘DQ‘I‘IU‘IhUNN-‘OO‘DGNNG Ct

20

22
26
27
28
28

List of References

CHAPTER 2. Field germination response of seven tropical
species of vegetative cover

Introduction
Materials and Methods
Introduction
Characterization of soil resources and weather
Seed germination experiments
Species selection
Use of thermal time
Statistical design and analyses
Results and Discussion
l. Agricultural context: soil resources and weather
ll. Field germination response and comparison to
laboratory data

Field germination response of benchmark species:

lettuce and wheat
Field germination response of tropical species
Weed competition and insect damage in field
experiments
Reporting of laboratory vs field germination data
Field data as actual germination percent
Comparison of field and laboratory data
Conclusions
List of References

CHAPTER 3. SociO-economic factors related to use of
vegetative cover at a tropical field site

Introduction

Materials and Methods

Results and Discussion
Introduction
Demographic information
Agriculture and farming
Gardening
Health and nutrition
Quality of life
Vegetative cover

Conclusions

List of References

CHAPTER 4. Ecological and remote sensing analyses of a Caribbean
village: a case study from the Dominican Republic

30

56

56
57
57
58
60
61
61
62
62
62

64

64
65

66
67
68
69
70
71

97

97
98
99
99
99
100
102
102
103
103
104
106

110

Overview of international development and argument for a new
approach
Buen Hombre: a tropical case study
Marine and terrestrial ecosystems
I. Reef and coastal mangrove ecosystems:
general background
ll. Reef and coastal mangrove ecosystems of Buen Hombre
A. Population
1. Low population
2. Low population density
8. Physical environment
C. Conservation ethic
III. Terrestrial Ecosystems of Buen Hombre
A. Land use
B. Soil resources
C. Transacts
IV. Human Factors
V. Relationships between ecosystems and human
activity systems
VI. The natural resource situation in Buen Hombre
Conclusions
List of References

SUMMARY AND CONCLUSIONS

APPENDIX 1. Buen Hombre survey questionnaire

110
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116

116
118
119
119
119
120
121
122
123
125
126
128

130
131
134
137
162

166

LIST OF TABLES

CHAPTER 1

Table 1. Selected species with potential as cover crops in harsh
environments, characterized in laboratory germination studies

Table 2. Experimental conditions for germination W
experiments, water not limiting (w = near-saturation)

Table 3. Experimental conditions for germination W
experiments, temperature not limiting (20—30°C)

Table 4. Seeds per replication by species for substrate experiment

Table 5. Reported and experimentally determined base temperatures
for selected species

Table 6. Seed moisture %: initial and final in W
experiments (near-saturation)

Table 7. Seed moisture %: initial and final in water pgtential
experiments l20-30°C night-day temperatures)

Table 8. Maximum germination percent as affected by substrate medium
in growth chamber experiments (20-30°C, near-saturation water potential)

CHAPTER 2

Table 1. Selected species with potential as cover crops in harsh
environments, characterized in field germination studies

Table 2. Buen Hombre field experiments: species and number of seeds
per replication

Table 3. Soil profiles of "black" and "yellow" soils, Buen Hombre

Table 4. Classification of black and yellow soils, Buen Hombre

xi

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36

37

38

39

40

41

42

73

74
75

76

Table 5. Soil fertility of the three major Buen Hombre soil types, as
designated by farmers

Table 6. Maximum cumulative germination, a comparison of field and
laboratory data

Table 7. Maximum cumulative germination, a comparison of laboratory
experiments using Buen Hombre soil medium to field experiments in Buen
Hombre

CHAPTER 3
Table 1. Household composition of farming families, Buen Hombre

Table 2. Factors that would improve life for families and village
as a whole, Opinions of farmers and wives, first five mentions

CHAPTER 4

Table 1. Quality of drinking water in Buen Hombre district, sampled
April 15, 1992

Table 2. Land use classification system for Buen Hombre (based on CEUR-
CARTEL system) (Source: St.-Pierre, personal communication)

Table 3. Land use distribution, Buen Hombre District: 1958, 1966, 1984
(Source: St.-Pierre, unpublished data)

Table 4. Type of land use by general category, Buen Hombre District
(Source: St.-Pierre, unpublished data)

Table 5. Population for Buen Hombre District', 1935-1981 (Source:
Castillo, National Census, Dominican Republic, 1936, 1951, 1961 , 1971,
1982)

Table 6. Degree of intensity of land use, Buen Hombre District: 1958, 1966,

1984 (Source: St.-Pierre, unpublished data)

Table 7. Degree of erosion risk potential, Buen Hombre District: 1958, 1966,

1984 (Source: St.-Pierre, unpublished data)
Table 8. Plant species identified by villagers, Buen Hombre

Table 9. Tree species identified by villagers, Buen Hombre

xii

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79

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142

144

144

145

146

146
147

150

LIST OF FIGURES

CHAPTER 1

Figure 1. Germination rate by temperature for jack been with base
temperature estimated from x-intercept

Figure 2. Mean cumulative germination percent and standard deviation (5)
of m in response to a) temperature, b) water potential

Figure 3. Mean cumulative germination percent and standard deviation (s)
of M95]: in response to a) temperature, b) water potential

Figure 4. Mean cumulative germination percent and standard deviation (3)
of W in response tO a) temperature, b) water potential

Figure 5. Mean cumulative germination percent and standard deviation (5)
Of W in response to a) temperature, b) water potential

Figure 6. Mean cumulative germination percent and standard deviation (5)
of W in response to a) temperature, b) water potential

Figure 7. Mean cumulative germination percent and standard deviation (S)
of Wildly in response to a) temperature, b) water potential

Figure 8. Mean cumulative germination percent and standard deviation (5)
of MILDRED in response to a) temperature, b) water potential

Figure 9. Mean cumulative germination percent and standard deviation (3)
of Will]! in response to a) temperature, b) water potential

Figure 10. Mean cumulative germination percent and standard deviation (3)

of W in response to a) temperature, b) water potential

Figure 11. Mean cumulative germination percent and standard deviation (3)

of W in response to a) temperature, b) water
potential

xiii

43

44

45

46

47

48

49

50

51

52

53

Figure 12a. Mean cumulative germination percent of Wm!) as

affected by pro-treatment at 20-30°C and 30-40°C

Figure 12b. Mean cumulative germination percent of we; as affected by
pro-treatment at 20-30°C and 30-40°C

Figure 13. Cumulative germination of Mailbag as affected by blotter
paper substrate and soil substrate

CHAPTER 2

Figure 1. Photographs of: (top) experimental field plots, Buen Hombre,
Dominican Republic, and (bottom) M. Perez, watering one microplot

Figure 2. Average daily surface soil and air temperatures, Buen Hombre:
a) March-April, 1992 b) September-October, 1991

Figure 3. Mean solar radiation, Buen Hombre: March-April, 1992, and
September-October, 1991

Figure 4.Mean density (N) and standard deviation (5) of germinated and
ungerminated Meat seeds in the field: a) March-April and b) September-
October

Figure 5. Mean density (N) and standard deviation (5) of weeds and
germinated and ungerminated Iablab seeds in the field: a) March-April
and b) September-October

Figure 6. Mean density (N) and standard deviation (3) of weeds and
germinated and ungerminated bird-rgsistan; sgrghum seeds in the field:
a) March-April and b) September-October

Figure 7. Mean density (N) and standard deviation (5) of weeds and
germinated and ungerminated sunnhemp seeds in the field: a) March-April
and b) September-October

Figure 8. Mean density (N) and standard deviation (s) of weeds and
germinated and ungerminated mm seeds in the field: a) March-April
and b) September-October

Figure 9. Mean density (N) and standard deviation (3) of weeds and
germinated and ungerminated W seeds in the field:
a) March-April and b) September-October

Figure 10. Photographs of: (top) white velvet bean seeds that have

turned black and subsided into the soil, and (bottom) sunnhemp
seedlings with insect damage

xiv

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55

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84

85

86

87

88

89

Figure 11. Actual vs. cumulative germination percent of tropical velvet
bean in the field

Figure 12. Mean percent (%) and standard deviation (3) of germinated
and ungerminated wheat seeds in the field: a) March-April and
bl September-October

Figure 13. Mean percent (%) and standard deviation (s) of germinated
and ungerminated Iablab seeds in the field: a) March-April and
b) September-October

Figure 14. Mean percent (%) and standard deviation (5) of germinated

and ungerminated WM seeds in the field:
a) March-April and b) September-October

Figure 15. Mean percent (%) and standard deviation (s) of germinated
and ungerminated MIME seeds in the field: a) March-April and
b) September-October

Figure 16. Mean percent (%) and standard deviation (5) of germinated
and ungerminated tepary seeds in the field: a) March-April and
b) September-October

Figure 17. Mean percent (%) and standard deviation (5) of germinated
and ungerminated W seeds in the field: a) March-
April and b) September-October

CHAPTER 3
Figure 1. Seasonal labor and precipitation calendar, Buen Hombre
CHAPTER 4

Figure 1. Map of Dominican Republic with study site of Buen Hombre on
northwest coast (redrawn from tourist brochure)

Figure 2. 1985 Landsat satellite image of northwest coast of Dominican
Republic, showing bleached off-shore reefs (photo provided by T. Wagner,
Environmental Research Institute of Michigan)

Figure 3. Map of Buen Hombre Census District, showing fresh water
sources, mangrove and coral reef systems (boundaries based on census
map boundaries)

Figure 4. Graphic representation of combined factors of slope, land
use and vegetative cover, used to determine erosion risk potential

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154

155

156

Figure 5. Buen Hombre land use: 1958. 1966 and 1984. (Modified
and redrawn from unpublished CEUR-CARTEL data provided by
St.-Pierrel

Figure 6. Buen Hombre land use intensity: 1958, 1966 and 1984.
(Modified and redrawn from unpublished CEUR-CARTEL data provided
by St.-Pierrel

Figure 7. Buen Hombre erosion risk potential: 1958, 1966 and 1984.
(Modified and redrawn from unpublished CEUR-CARTEL data provided
by St.-Pierre)

Figure 8. Transact Of developed agricultural land, village of
Buen Hombre

Figure 9. Transact of undeveloped agricultural land, village of Buen
Hombre

157

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159

160

161

INTRODUCTION

Much of the cultivated land in the world is subjected to varying degrees of
physical, chemical and biological degradation in the forms of erosion, acidification,
salinization, compaction, nutrient and organic matter depletion (Lal and Stewart,
1990; Postal, 1989). The control of these processes and amelioration of their
effects is critical to long-term sustainability of agricultural ecosystems globally. Key
among the technical solutions to problems Of land degradation is the maintenance of
vegetative cover on the soil, particularly during non-crop periods when rates of
degradation are high. Though conceptually simple, vegetative covers are not used
extensively in agricultural management systems. While the reasons for this are
Often related to SOCiO-cultural factors, a major technical limitation is correlated with
poor germination of vegetative cover species when seeded on the soil surface,
rather than sown in traditional ways. Aerial, or broadcast, seeding Of cover crops is
critical, since it is Often necessary to seed into an existing crop and/or the
economics do not favor sowing cover crops by traditional methods. In developing
regions, for example, lack of available labor and the mechanics of shifting
agriculture may require cover crops to be seeded on the soil surface.

Another problem in the utilization of cover crops is that plant species currently
being used for vegetative cover may be inappropriate, particularly if surface seeding
is the primary method of establishment. Though cover crops have long been used
in crop rotations in the tropics, until recently most research on cover crops has been

conducted in temperate regions with temperate species (Kretschmer, 1989).

2
Research methodology developed for temperate species "generally has not been
successful” with tropical species due to ”lack of knowledge of the diversity,
adaptability and reasons for persistence in tropical species" (Kretschmer, 1989).

An additional concern is that of the research conducted in developing
countries, "far too much has been done on fertile experimental stations, or with
chemical fertilizers, thereby making it virtually useless to small farmers” (Bunch,
1987). Most green revolution innovations depend on high external inputs applied in
low-risk environments. The resulting technology has been inappropriate for
subsistence farmers tilling small-scale, complex, diverse farms in risk-prone
environments (Chambers at al., 1989).

Two major technical problems limit the use of vegetative cOvars in controlling
land degradation and restoring productivity to degraded lands. The first is
identification Of plant species for use as cover crops, and the second is improved
germination of seeds sown on the soil surface. The ideal plant species must be able
to germinate under harsh environmental conditions, particularly since water is often
limiting at the soil surface, and availability of water is one of the most important
factors affecting seed germination (Berkat and Briske, 1982). Though Optimum
conditions for germination are known for many species (AOSA, 1988; ISTA, 1985),
boundary conditions are known for only a few (J. A. Zeevart, personal
communication).

The purpose of this research was fourfold. One objective was to determine
boundary conditions for germination in a controlled laboratory environment. Species
selected for testing were under-researched, tropical species with potential for harsh,

limiting environments. Because subsistence villagers Often lack food at the and of

3
the dry season and because erosion can be severe with the first intense reins of the
rainy season, when the ground is bare and unprotected, species selected for testing
as part of the first objective also had to have potential for providing ground cover
during the dry season and for producing human food, stock forage or income.

Since germination and early growth are critical to the establishment of
vegetative cover in degraded environments, the investigation was limited to those
two growth stages as a rapid screening technique. Therefore, the second Objective
was to develop a rapid screening method of species selection for full-scale testing in
the field. This addressed the question as to whether surface germination
experiments in the lab could be used to establish minimum threshold levels for
species establishment and subsequently be used as a general predictor of surface
germination and early growth in the field.

Because of the multidisciplinary nature Of problems of soil degradation, the
third objective was to ascertain whether local problems of marginal land use and
subsistence farming in the vicinity of the field test site (village of Buen Hombre,
Dominican Republic), could be alleviated by dry season cover crops and whether
sociO-aconomic factors would lead to acceptance or rejection of cover crop
technology. Finally, the fourth objective was to characterize ecological and human
environments at the tropical field site to determine whether use of vegetative cover
was appropriate at a macro-level.

This dissertation addresses each of the four Objectives in a chapter, with
boundary conditions for germination of selected species, based on controlled
laboratory experiments, summarized in Chapter 1, field germination response and a

comparison Of field and laboratory data in Chapter 2, the sociO-economic context

4
into which vegetative cover crops would be introduced, described in Chapter 3 and
key ecosystems and their related human activity systems characterized in Chapter
4. An overall summary and conclusions ties the four Objectives and their

corresponding research projects together in a brief final discussion.

LIST OF REFERENCES

Association of Official Seed Analysts (AOSA). 1988. Rules for testing seeds. J.
Seed Technol. 12(3): 1-122.

Bunch, R. 1987. Green manure crops. In Price, M.L., ed., Echo Development Notes
12: 1-8. North Fort Myers, FL., ECHO.

Chambers, R., A.J. Pacey, and LA. Thrupp. eds. 1989. Farmer first: farmer
innovation and agricultural research. London, England: Intermediate Technology
Publications.

International Seed Testing Association (lSTA). 1985. International Rules for Seed
Testing. Seed Science and Technology 13: 299-51 3.

Kretschmer Jr., A.E. 1989. Tropical forage legume development, diversity and
methodology for determining persistence. In Marten, G.C. et al., eds.
Persistence of forage legumes. Madison, WI: American Society of Agronomy,
CSSA, SSSA.

Lal, R. and B.A. Stewart. 1990. Soil degradation, a global threat. In Lal, R. and B.A.
Stewart. (Editors). Advances in Soil Science, Volume 11: Soil Degradation.
New York, NY.: Springer-Verlag.

Postal, S. 1989. Halting land degradation. In Brown, L.R. at al., (Editors). State of
the World 1989. New York, NY.: W.W. Norton and Co.

CHAPTER 1

BOUNDARY CONDITIONS OF GERMINATION FOR EIGHT SPECIES OF

VEGETATIVE COVER WITH POTENTIAL FOR THE TROPICS

INTRODUCTION

Traditional, applied agronomic research generally includes four phases:
defining an agricultural problem, developing hypotheses related to potential
solutions, testing those hypotheses in laboratories, greenhouses or field plots and
than evaluating their effectiveness at increasing yield, reducing erosion, reducing
economic, labor or energy costs, etc. In this chapter, several constraints to the use
Of vegetative cover crops in the tropics are inveStigatad using the traditional
approach. There are a number of under-researched cover crop species with great
potential for use by subsistence farmers in the tropics for erosion control and dry
season food production. However, use of vegetative cover is restricted, partly due
to a lack of data on suitability of specific crops for specific environments.

The Objective Of this study was to develop a screening procedure for species
selection for harsh environments. Species chosen for use as aerial-seeded cover
crops had to be able to withstand harsh conditions at the soil surface. Thus, the
screening procedure involved determining boundary conditions for germination of a
minimum parameter set (temperature and water), under light conditions

approximating those at a tropical field site. Laboratory data were later compared to

7
field data (Chapter 2), and the laboratory procedure was evaluated for effectiveness
as a rapid screening technique. A brief review of seed germination is presented
below as background context for a discussion of experimental data that follows.
Germination response to temperature and water potential under controlled

laboratory conditions will then be discussed.

OVERVIEW OF SEED GERMINATION

Seed Dormancy

Seed dormancy, the state in which mature imbibed seeds fail to germinate, is
an evolutionary safeguard against unpredictable natural environments (Hillel, 1972;
Meyer and Poljakoff-Mayber, 1975). As a survival mechanism, dormancy allows
seeds to avoid potentially destructive environmental stresses. Under natural
conditions, the breaking Of dormancy generally results in a range of germination
times for the population of individual seeds of a species (Hillel, 1972). This strategy
Of non-uniform germination prevents local extinction of a species due to severely
detrimental conditions (Mayer, 1980/81 ). Before dormancy is broken and
germination begins, the environment must provide a set of physical and chemical
cues, indicating that optimal conditions for germination exist. These conditions are
specific to each species. In addition, water must be imbibed and the physiological
blocks of dormancy must be removed by certain metabolic events (Heydecker,

1977; Hillel. 1972).

Germination and Water Uptake

Germination is quantifiable, begins with imbibition Of water by the seed and
ends with protrusion of part of the embryo, usually the radicle, through the seed
coat (Mayer, 1980/81). Water uptake is essential to germination and involves three
distinct phases: an initial phase of rapid water uptake, which then decreases and
plateaus into a transition or lag phase Of negligible uptake, followed by a third phase
Of rapid, increased water uptake (Bradford, 1986; Hadas, 1982; Haigh and Barlow,
1987; Hegarty, 1977). This last phase, the growth phase, ends with radicle
emergence, occurs only in viable, non—dormant seeds and occurs only when the
seed has reached a threshold water content, as opposed to a specific seed water
potential, that is specific to the species (Bradford, 1986; Hunter and Erickson,
1952; Prokof'ev et al, 1983). However, individual seeds within a seed lot vary
somewhat both in the substrate water potential and in the moisture percent at
which germination occurs, and low vigor seeds may require higher seed moisture
contents for germination (Hegarty, 1978).

In the initial phase, viable and non—viable seeds with very low water potentials
(down to about -1OO MPa) imbibe water equally well (Barrie, 1984; Hegarty, 1978;
Villiers, 1972). The process is purely physical and results from a large gradient for
water uptake (Bradford, 1986; Meyer and Poljakoff-Mayber, 1975: Villiers, 1972).
During the second, or transition, phase of steady water content, there is metabolic
activity, respiration begins and new cells are formed (Hegarty, 1977). During the
third phase, water uptake depends more on osmotic and pressure potential. In
order for germination to occur at the end of this phase, the seed's metric potential

muSt be greater than about -1.5 to -2.0 MPa in most species, though seed water

9
content is the critical variable for radicle emergence (Bradford, 1986; Kaufman and

ROSS, 1970).

Germination and Temperature

Nomdormant seeds germinate over a wide range of temperatures. The
relationship during germination between rate of germination and temperature is not
the O"J Of a simple chemical reaction (Heydecker, 1977). The relationship is linear
between a minimum "base” temperature and an optimum temperature, at which the
highest percent of seeds germinate in the shortest time (Garcia-Huidobro at al,
1982; Haydecker, 1977; Hillel, 1972; Meyer and Poljakoff-Mayber, 1975). Beyond
the Optimum up to maximum temperatures, percent germination decreases. Below
the base temperature and above a maximum temperature, germination simply does
not occur.

Base temperature may vary for seed lots of the same variety, depending on
conditions under which the parent plant produced seed (Hardwick (1972),
Harrington (1972) and Hegarty (1972) in Heydecker, 1977). Some data suggest
that the base temperature for germination is genotypic, that all seeds Of a species
have a common base temperature and that the difference lies in the amount of
thermal time, or the accumulated temperature, required for germination (Ellis and
Butcher, 1988; Garcia-Huidobro at al., 1982). Seed physiological age also affects
temperature requirements for germination, with optimum temperature becoming
broader and higher with age of seed (Langridge and McWilliam, 1967).
Additionally, some seeds germinate at a specific temperature, while others require

diurnal fluctuations in temperature (Garcia-Huidobro at al, 1982; Meyer and

10

Poljakoff—Mayber, 1975).

Germination and Light

The environmental conditions under which a parent plant produces seeds
affects light sensitivity within a seed lot. Thus, germination response to light varies
greatly both by and within species (Vidaver, 1977). As a prerequisite to
germination, some species require long exposures to light. Others require darkness,
intermittent light exposure or different length photoperiods. Other species
germinate regardless of light conditions (Mayer and Poljakoff-Mayber, 1975;
Vidaver, 1977). When red light exposure is required to break dormancy and initiate
germination, the light effect depends on both light intensity and duration (Mayer and

Poljakoff-Mayber, 1975).

Temperature-Water-Light Interactions and Germination

Stress to seeds due to temperature or water alone can trigger a dark or light
requirement for germination, as can interactions between light and water stress,
temperature and water stress or between temperature and light (Heydecker, 1977).
Certain light conditions can also permit germination at unfavorably high
temperatures for some species (Mayer and Poljakoff-Mayber, 1975). And
interactions between water and temperature are such that a seed's threshold water
potential is lowest at the seed's Optimum temperature (El-Sharkawi‘and Springuel,

1977; Fyfield and Gregory, 1988).

1 1

Laboratory Data as a Predictor of Field Germination

When laboratory data is used as a predictor of seed germination response in
the field, it can serve only as a general indicator of possible germination success or
failure in specific environments. The laboratory conditions under which seeds are
usually studied do not exist in fields, and constantly changing field conditions in the
seed-soil-water-atmosphere micro-environment cannot be duplicated in laboratories
(Koller, 1972). In lab experiments, constant temperatures and unnatural water
cycles varying from near total water immersion to no water, accompanied by
complete aeration, are standard. In nature, interactions between environmental
factors control germination in a number of ways. For example, diurnally alternating
temperatures, the time factor involved in amplitude of temperature cycles and the
damping of amplitude with soil depth provide seeds with complex temperature
information and conditions, compared to that provided by one constant lab
temperature (Koller, 1972). "The temperature relations of germination observed
under laboratory conditions are not simple, straightforward indicators of the degree
to which germination is temperature-regulated under natural conditions. In fact,
they can at times be quite misleading” (Koller, 1972). In addition, environmental
stresses do not occur singly in nature, but as a complex, and seed response to
environmental Stress varies, even for seed lots of the same genus (Pollock and
Roos, 1972).

Hades (1982) describes the environment of a seed in terms of seed-soil water
relations. As soil metric potential (4!...) decreases, there is a substantially greater
decrease in seed germination, because a decrease in soil rpm in the seed's micro-

environment causes a decrease in water conductance to the seed. On the other

1 2
hand, seed swelling during imbibition may increase seed-soil contact to some
extent, because Hades (1977) found good correspondence between similar osmotic

solution potentials in laboratory experiments and soil metric potentials in the field.

MATERIALS AND METHODS
Several sets Of germination experiments were conducted in a growth chamber
to characterize germination response of selected species to temperature, water

potential and pre-chilling treatments.

Species Selection

Plant species (Table 1) were selected for inclusion in this study based on
specific criteria and information gathered from five different sources (Martin and
Ruberte, 1980; McLeod, 1982; National Academy of Science, 1979; Price, 1981-
1989; Ritchie, 1979). Each tropical species was selected because it was under-
utilized and under-researched, had low management requirements, made efficient
use Of water, was adapted to either marginal lands or dry lands and had high
nutritional value if it was a food/ forage-producing species. In addition, a number of
species were selected for their nitrogen-fixing ability and production of multiple,
edible plant parts. One species (sunnhemp) was inedible, but had many of the
above traits and was selected for its income-producing potential. Two temperate
species, Grand Rapids lettuce and wheat, were also selected for testing because
they were wall-researched cultivars in germination work (Barrie, 1985; Meyer and
Poljakoff-Maybar, 1975). They were used as benchmark species to test the validity

of the experimental methods used. Seeds Of seven indigenous species were

1 3
collected at the field site for testing and comparison to introduced species.
Seeds were ordered from the US. Department of Agriculture, Ferry-Morse
Seed Company, Native Seeds/Search (Tucson, Arizona), Setropa Limited (Bussum,
Holland), M/S Inland and Foreign Trading Company (Singapore) and the College of

Tropical Agriculture (University of Hawaii).

Germination test procedures

All germination experiments were conducted in a Conviron1 growth chamber
with a Conviron CMP 3244 Controller (Conviron Products of America, Pembina,
North Dakota 58271 ), programmed for a constant relative humidity of 65% and 12-
hour night/day periods of 10-20°C, 20-30°C, 30-40°C, or 35-45°C, with low
temperatures in darkness and high temperatures accompanied by a photoperiod of
1,270 nM sec" of light. Because relative humidity may influence relative growth
rates, and because relative growth rates characterize competitiveness (K. A.
Renner, personal communication), percent relative humidity, as well as photoperiod
length, were maintained at levels approximating conditions at the Dominican
Republic field site as much as possible.

Seeds selected for germination experiments were not visibly damaged and
were selected without regard to size or color. Seeds were germinated in either 150
mm- or 100 mm-diameter Petri dishes, or in 30.5 x 30.5 x 2.5 cm plexiglass trays,

on one thickness of standard blue germination blotter paper moistened with distilled

 

1 Mention of the trade name, proprietary product or vendor does not constitute a
guarantee or warranty for the product by Michigan State University or the author, and
does not imply its approval to the exclusion Of other products or vendors that may be
suitable.

14
water. At twice daily intervals for the first five days and daily intervals afterwards,
lids and sealed plastic wrap covering germination containers were removed to
aerate, count and remove germinated seeds. Moldy seeds were removed as they
occurred. Seeds were considered germinated upon radicle protrusion from the seed
coat.

In most cases, experiments lasted until no germination had occurred for five
successive days. Germinated seeds were counted, rinsed, air-dried for one hour
(amaranth, hierba more, lettuce) or dried with a vacuum funnel, weighed, ra-dried
and re-weighed in a 70°C oven for 48 hours to Obtain seed water content at
germination as a percent of seed dry weight. Initial seed water content prior to the
beginning of germination experiments was also determined for each species. Initial
seed moisture percent was determined only once on seed samples Of 50 (jack been,
Iablab bean, tropical velvet been), 200 (tropical kudzu, sunnhemp, tepary been,

wheat) and approximately 1,000 (amaranth, lettuce) seeds.

Temperature experiments

An experiment of germination response to four temperature regimes was
conducted at the alternating temperatures listed above. Distilled water was added
daily to germination containers to maintain water content at near—saturation
throughout the experiment. Each temperature treatment consisted of four
replications of varying numbers of seeds by species, depending on availability (T able

2).

15
Water potential experiments

An experiment investigating germination response to four different water
potentials was conducted at 20-30°C (approximate field site night-day
temperatures) with daily additions of distilled water to approximate near-saturation
and at -0.5, -1.0 and -1.5 MPa of water potential with high molecular weight
solutions. Four replications of each species of seeds for each treatment (Table 4)
were germinated at 20-30°C in 150 mm Petri dishes on blotter paper, or in 30.5 x
30.5 x 2.5 cm plexiglass trays, on 64 mm-thick styrofoam board wrapped in 2
layers of cheesecloth with a hole and cotton wick inserted in the center of the
board and cheesecloth, with two rectangular pieces of blotter paper resting on top.
The styrofoam board floated on a reservoir of polyethylene glycol [H(OCH,CH,)00H],
or PEG, solution. Initially, blotter paper at the surface was wet thoroughly with PEG
solution and then rewet in sections where the wick system failed to keep blotter
paper sufficiently wet.

One of the major successes in germination research involves simulation of
seed-soil water conditions. Very high molecular weight osmotic solutions have
been used as a laboratory substrate to apply moisture stress to germinating seeds
and simulate soil metric potentials in the field (Hades, 1977; Hades, 1982; Pollock
and Boos, 1972). It is assumed that because osmotic potential in most agricultural
soils is negligible, the osmotic stress of non-reactive, high molecular weight
solutions can be used to simulate metric potential. This is, in fact, the case. Hades
(1977) germinated three large- and small-seeded species in PEG solutions of
different water potentials and found good agreement between final germination

percent in the field and that predicted by performance in the lab.

1 6

In the water potential experiments conducted for this study, PEG, with an
average molecular weight of 8,000 (Aldrich Chemical Company, Milwaukee,
Wisconsin 53201), was mixed with distilled water, according to the following
formula, to produce solutions at -0.5, -1.0 and -1.5 MPa of water potential:

I”: o.130u=rsc;12 T - 13.7 [PEGl’

where w is solution water potential in MP3, [PEG] is PEG concentration in 9 PEG g"
or ml" of water and T is temperature in °C (Hardegree and Emmerich, 1990).
Because growth temperatures alternated between equal 12-hour periods at 20 and
30°C, calculations were made for each temperature and the mean of the two
calculated 9 PEG ml" H20 for each temperature was taken. These calculations
resulted in 0.2122 9 PEG ml" water for -0.5 MPa, 0.3098 g PEG ml" water for -1.0
MPa and 0.3794 9 PEG ml" water for -1.5 MPa.

When used as a germination substrate, filter or blotter paper may concentrate
PEG solution and decrease water potential in the solution-paper matrix (Hardegree
and Emmerich, 1990). The magnitude of this effect depends both on original PEG
solution concentration and the ratio of solution volume to paper dry weight.
However, if the ratio of PEG solution volume to dry substrate paper weight is
greater than 12 and if measures are taken to prevent evaporation from Petri dishes,
the concentration effect of the paper substrate can be minimized (Emmerich and
Hardegree, 1990; Hardegree and Emmerich, 1990). Accordingly, the ratio of PEG
solution volume to dry substrate paper weight in these experiments was maintained
at or above 14.

In addition, to inhibit evaporation of water from the PEG solution, germination

trays/dishes were tightly covered with polystyrene lids (in the case of Petri dishes)

1 7
or commercial household plastic wrap (in the case of plexiglass trays). Germination
trays/dishes were replenished with PEG solution as needed to dampen the blotter
paper and prevent zones of solute accumulation with lower water potential near
germinating seeds and to simulate daily watering of field plots. Lids and plastic

sealing wrap were removed daily for aeration.

Pro-treatment experiment

In the temperature experiment discussed earlier, lettuce, amaranth and wheat
seeds (Table 2) were pre-treated to break dormancy, according to AOSA procedures
(Association of Official Seed Analysts, 1988). This was done for comparison to
previous germination research, in which standard practice involved the pre-
treatment of certain species. Wheat pre-treatment involved pro-chilling for 3 days
at 4°C on dampened blotter paper. Amaranth pre-treatment also involved pre-
chilling, however blotter paper was dampened with a 0.2% KNO3 solution, rather
than distilled water (Association of Official Seed Analysts, 1988).

A separate pre-treatment study was completed to compare response of
amaranth and wheat with and without pre-treatments at 12-hour periods of 20-30°C
and 30-40°C under 1,270 nM sec" of light during the high temperature period.
Lettuce was not included in the pre-treatment studies, as it responded poorly at
these temperatures. Four replications of each species were germinated in Petri

dishes with one layer of blotter paper at each temperature regime.

Substrate experiment

All germination experiments described above were completed on blotter paper.

1 8
A substrate experiment was conducted to ascertain whether a soil substrate, using
soil taken from the Dominican Republic field site, would affect germination response
in the growth chamber. A plastic box 48 x 36 x 5 cm was filled to a depth of 3 cm
with surface (0-7.6 cm) soil taken from a composite of 30 soil samples collected at
the perimeter of experimental plots in the village of Buen Hombre (Chapter 3). The
box was sectioned into 4 quadrants, each representing one replication. A specific
number of seeds (Table 5) from each species was placed at the surface and grown
at 20-30°C. Data from this experiment were compared to germination data for
seeds germinated on blotter paper in Petri dishes at near-saturation under identical

growth chamber conditions.

Dormancy-breaking experiment

Seeds from six of seven species collected at the field site did not germinate
under laboratory conditions. Therefore, in a final experiment to investigate
dormancy of indigenous species, a series of pre-treatment tests were conducted on
one of the six species, cardo santo (Argemone mexicana), in order to break
dormancy. Pre-treatments included treatment with 0.2% KN03, mechanical
scarification, acid treatment (a two minute soaking in concentrated sulfuric acid,
rinsed in tap water and pre-chilled at 4°C for 12 hours), pre-heating at 104°C for 45
minutes and pre-treatment with gibberellic acid (concentration of 1,000 mg I").
None of these pre-treatments succeeded in breaking dormancy, so only experiments
with the indigenous species hierba more were successful in terms of the occurrence

of germination.

19
Use of thermal time

Germination data in this chapter are reported in thermal time, or accumulated
temperature. Between the base and optimum temperatures for a species, the
relationship between germination rate, or the time to 50% of final germination, (t")
and temperature is linear (Angus et al., 1980/81a; Garcia-Huidobro et al., 1982;
Kanemasu et al., 1975; del Pozo et al., 1987). In most cases, time to 50%
germination is directly proportional to temperature. Since the seed's time scale is
strongly related to its thermal environment, thermal time can be defined as a seed's
view of time (Ritchie and NeSmith, 1991). Thermal time is useful for comparing
germination within and between species in different regions and climates. The
mathematical formula for thermal time, "growing degree days," or °Cd (Ritchie and
NeSmith, 1991), is based on the sum of the mean daily temperature minus the base
temperature of a particular species for the total number of days to germination:

°Cd = {WM - Tb...)

Base temperature was calculated for each species in the study, using a
mathematical relationship described by Monteith (1977), in which rate of
germination (or inverse of time in days to germination of a percentage of the
germinating population) was plotted against mean temperature at which germination
occurred (Covell et al., 1986; del Pozo et al., 1987; Lawlor et al., 1990; 0ng and
Monteith, 1985). Linear regressions fitted to the data points produced base
temperature as the x-intercept. Normally, this calculation is based on multiple
points of data obtained from germinating seeds on a thermogradient plate having
small increments of temperature over a wide range of constant temperatures.

However, one of the objectives of this study was to develop general indicators of

20
germination response based on a minimum dataset of variables. Therefore,
temperature data were obtained in most cases for only three or four points, and
base temperature determinations were considered to be no more than rough
estimates. Base temperatures were based on values reported in the literature or
data determined from this study (Table 5). As an example, Figure 1 illustrates the
determination of the base temperature of 14°C used for jack bean thermal time

calculations in this study.

Statistical design and analyses

In the experiments above, there were four replications of each species in a
factorial design with species, time, temperature or water potential and pre-treatment
or substrate as factors in the analyses of variance. The data in the temperature,
water potential, substrate and pre-treatment experiments showed highly significant
differences between species, times and substrate or pre-treatment and between

time by species.

RESULTS AND DISCUSSION
Temperature and water potential experiments: benchmark species
In this study, wheat and lettuce have been designated as model species for
characterization of germination in stressful environments. The entire lettuce
population, in the top graph of Figure 2a, germinates immediately at optimum
temperatures for lettuce (10-20°C). These data agree with previous research (Khan
et al., 1978). At higher temperatures (20-30°C), rate of germination is slowed, and

final cumulative germination percent is reduced. Inability of lettuce to germinate at

21
temperatures above 25-35°C, with threshold temperature depending on cultivar,
variety and seed lot (Hegarty and Ross, 1979: Saini et al., 1986), is characteristic
(Berrie, 1984; Heydecker, 1977; Khan, 1977). The percent standard deviation
plotted at the bottom of Figure 2a, with one standard deviation point corresponding
to each data point in the plot above shows that as lettuce seeds experience
temperature stress at temperatures above 25°C, variance increases. At even higher
temperatures of 30-40°C and 35-45°C, lettuce fails to germinate entirely. For this
reason, lettuce serves as an inadequate benchmark species for germination research
in the tropics. At temperatures of 20-30°C, with decreasing water potential, lettuce
germination rates and amounts drop and variance increases dramatically (Figure 2b).

The second baseline species is wheat. Figure 3 shows that wheat
performance is better at lower temperatures and higher water potentials, with
decreases in rate, decreases in final amounts and increases in variance under stress
due to temperature or water. These wheat data correspond well to previous
research (Ashraf and Abu-Sharka, 1978; Hanson, 1973; Kaufman and Ross, 1970).
Because germination occurs at all but the highest temperatures and lowest water
potentials, wheat is a good benchmark species for germination research of tropical
species.

Analysis of the data in these two graphs suggests that variance provides
information about a seed under stress and the stability of its response that may be
just as important to characterization of a seed's response as germination variables
are. For that reason, graphs in this chapter were designed to display both means

and standard deviations clearly.

22
Temperature and water potential experiments: eight tropical species

Germination rates for amaranth (Figure 4a) at all temperatures between 10 and
45°C are high, but variance is highest at low temperatures, indicating the seed is
under more stress at these temperatures. Though decreases in a: (Figure 4b) result
in decreases in both cumulative germination percent and rate of germination,
amaranth germinates at even the most severe water deprivation of -1.5 MPa of «I.

An indigenous species harvested from the tropical field site, hierba mora
(Figure 5), germinates most quickly at lower temperatures, has highest cumulative
germination percent at moderate temperatures (approximating those of its native
environment) and fails to germinate at temperature regimes above 30°C. In
addition, hierba mora does not germinate unless saturated conditions are present
and have persisted for more than 50°Cd of thermal time (Figure 5b). Then it
germinates quickly.

These data show that hierba mora possesses a survival mechanism appropriate
to its native, semi~arid environment of irregular, infrequent rainfall. If one combines
the water requirement with hierba mora’s temperature restriction, it is possible to
predict that hierba more will germinate in its native environment only in years when
there is persistent rain during the rainy season.

Rainy season at the Buen Hombre field site begins in November or December
and lasts until February or March, which is also the only time of the year that daily
air temperatures do not exceed 29 or 30°C. Surface soil temperatures would be
slightly higher, but would follow air temperatures. This may also indicate that only
buried seeds, where soil temperatures are cooler, will germinate.

Jack bean (Figure 6a) germinates well at all temperatures, but has a much

23
faster rate at 10-20°C, which would be important in a highly competitive
environment, for example, one with many indigenous weed species. As
temperature and stress to the seed increase, variance increases. And at all
temperatures, there is increased variance as germination percentage first increases.
This is followed by a decrease to minimal variance as final germination percentage
is approached, except at 30-40°C temperatures, which have high final variance.
Jack bean tolerates only mild water stress during germination (Figure 6b). Jack
beans resisted mold growth under experimental conditions much longer than any
other species.

Tropical kudzu (Figure 7) demonstrates a common survival mechanism, in
which there is great variability in the germination times of individual seeds, so that
germination of the population as a whole occurs over an extended period of time.
Rate and final cumulative germination percent are highest at 30-40°C and saturated
water conditions. Maximum final germination percentage occurs at near-saturation
and 30-40°C, with 49.5% :t 3.0%. It should be noted that maximum germination
percentage did not occur at 20-30°C until accumulated thermal time reached
612°Cd, or 68 days. This time-spread of germination is much longer than any of
the other species tested. At 35-45°C temperature regime, only seeds that
germinated quickly escaped mold growth and rotting.

Highest germination rates and final percentages for Iablab bean occur at
temperatures of 10-20°C and 30-40°C (Figure 8a) and at higher water potentials
(Figure 8b). Thirty-six percent of the seeds in the 20-30°C experiment (Figure 8a)
and the near-saturation experiment (Figure 8b) succumbed to a fungal pathogen,

resulting in unusually low germination rates and percentages for the near-saturation

24
41 seeds and those in the middle temperature range. Had those 36% of seeds
germinated, germination rates would presumably have been similar to rates at 10-
20°C and 30-40°C, and final germination percent would have been about 88%.
Again, variance is initially high in the temperature experiments and later drops, with
the exception of the 20—30°C seeds, which are under fungal pathogen stress.
Variance at all ws except -1.5 MPa, where minimal germination occurs, is high, with
greatest variance at the most stressful w of -1.0 MPa.

Sunnhemp reaches maximum germination percentage at all but the highest
temperatures, with only rate and standard deviation varying by temperature (Figure
9a). Fastest initial rate occurs at lowest and highest temperatures, with a lag in
rate at about 50% germination for the lowest temperatures. Variance is initially
high at 10-20°C and 30-40°C, with final standard deviation being lowest for the
lower temperatures and higher for the high temperatures. Each increase in water
stress results in substantial decreases in cumulative germination percent with
variance highest at higher metric potentials (Figure 9b). This increase in variance
under the least stressful water conditions is atypical for the species studied. In
some sunnhemp seeds, cotyledons emerged before radicles. Therefore, for
sunnhemp, as is true for some species, germination needs to be defined more
broadly as radicle 91 cotyledon emergence, whichever occurs first.

Tepary been responds well to higher temperatures, and has decreased
germination at 10-20°C, with a corresponding increase in variance at the coolest
temperature regime, indicating more stress and a less stable germination response
(Figure 10a). This species germinates well at all but the very driest conditions, and

variance shows the pattern of initial higher values that decrease upon reaching final

25
germination percentage and small increases in standard deviation with increasing
water stress (Figure 10b). At 35-45°C, approximately 90% of tepary seeds were
covered with mold by the third day of the study.

Unlike tepary, velvet been does poorly under even minimal (-0.5 MPa) water
stress and germinates best at the coolest temperatures tested. There is an
unexplained delay in germination rate and increase in variance at 20-30°C,
compared to temperatures just above and below 20-30°C (Figure 1 1). Velvet bean
was susceptible to fungi at 30-40°C and only those seeds quick to germinate
escaped senescence due to rotting. Variance was generally high for all treatments
and may be due to small sample size.

In summary, based on these experiments, amaranth and tepary are highly
adaptable species in terms of germination and are able to germinate at a wide range
of temperatures and water levels, from 10 to 45°C and 0.0 to -1.5 MPa. Sunnhemp
germinates at all temperatures tested and at all but the driest water potentials. One
would expect amaranth, sunnhemp and tepary to do well in tropical, water-limited
environments during the germination phase of growth.

Jack been, velvet bean and Iablab all require wet conditions for germination,
though all germinate in tropical temperatures. These three bean species are large-
seeded and once they have imbibed sufficient water and have germinated, are able
to put down roots rapidly and survive in very dry environments (Bunch, 1987;
Fenner, 1985; National Academy of Sciences, 1979). In fact, in a pilot experiment
(data not reported) at the tropical field site, a jack bean seedling that received rain
at Day 1, 3 and 5 after planting, produced a bush and 5 filled seed pods 3 months

later with no further precipitation.

26

Seed moisture percent at germination

Bradford (1986) and Hunter and Erickson (1952) report that seed moisture
percent, not seed water potential, is the trigger for germination and that each
species has a unique threshold level. Most germination literature reporting seed
moisture percent, reports the change in seed moisture percent from its initial, pre-
experiment value to its final moisture percent at germination (Bradford, 1986;
Hegarty, 1978), rather than just final germination moisture percent. Tables 6 and 7
report two values -- initial moisture percent on a dry weight basis and moisture
percent at germination, also calculated on a dry weight basis, for both the
temperature experiments (Table 6) and the water potential experiments (Table 7).

The smallest seeds tend to have high variation in weights. The nature of
germination studies often results in only a few seeds germinating on a particular
day, and when the seeds are very small, it is difficult to obtain accurate weights. A
possible solution to the problem would be to have large numbers of seeds per
replication for the smallest-seeded species. All the small-seeded species in this
study (amaranth, hierba mora, lettuce, wheat), except tropical kudzu, tend to have
lower moisture percents at germination, all less than 80% on a dry weight basis.
Large-seeded species and kudzu all have seed moisture percents above 88%.
These figures are lower than that reported by McDonough (1975), who found that
water content of tested grass seeds at germination ranged from 77 to 97% and that
water content of legume seeds ranged from 162 to 168%. Also, there is a
tendency for some species (Iablab, sunnhemp, tepary and velvet been) to show a
trend toward increased seed moisture percent with increased environmental stress.

Wheat tends toward decreased moisture percent with stress, though variance tends

27

to be high for these data.

Pro-treatment experiment

Prior to the temperature studies, wheat, lettuce and amaranth were pre-treated
(Table 2) to break dormancy and provide comparability to previous germination
research. In the pro-treatment study to examine the effects of pro-treatment on
germination rate and percent germination of amaranth and wheat, lettuce was
excluded because of poor germination response at study temperatures. These data
show that at 20-30°C, suboptimal germination temperatures for amaranth,
germination of untreated amaranth decreases 14% from pre-treated, and untreated
wheat has a slower germination rate, but similar final germination percentage, to
that of pre-treated wheat (Figure 12). At 30-40°C, an optimum temperature for
amaranth, untreated and pre-treated amaranth have similar germination rates and
percentages; while untreated wheat, under supraoptimal wheat temperatures,
shows reduced rates and germination percentages compared to pre-treated wheat.
The point is that pro-treatment tends to increase germination rate and/or final
germination percentage only when the seed is subjected to stressful germination
conditions. For comparison of laboratory data to other laboratory experiments, pre-
treatment should be done for comparability of results. But for comparison of lab to
field data, pre-treatment should be done only if it is possible and practical to treat
seeds in both laboratory and field studies. (It should be noted that while wheat,
lettuce and amaranth were pre-treated in laboratory temperature studies, they were
not pre-treated in the water potential experiments, because the date were to be

compared to field data and pre-treatment was not possible at the field site).

28
Substrate experiment

Figure 13 compares growth chamber germination of Iablab on blotter paper to
germination on soil from the Dominican Republic field site. Lableb response is
typical of that of all but one of the other species tested - faster germination rate,
but lower final germination percentage on the soil medium. What varies from
species to species is the magnitude of reduction in final germination percentage and
rate of germination.

Lettuce was the only exception to this trend, with a 59% increase in final
germination percent on the soil medium. This may be a result of lettuce seeds
falling into surface soil cracks and a reduction in seed temperature over that of
seeds on the blotter paper medium. These substrate data can be used as a species-
specific rate reduction factor in predicting field response from laboratory data (Table
8). Although not investigated in this study, possible reasons for the reduction of
germination on soil are the activity of soil pathogens, fungi or microbes; high soil

pH; variation in pore size; hydraulic conductivity or soil metric potential.

CONCLUSION
Using a traditional research approach to the use of vegetative cover in tropical
environments, the studies discussed above focused on one key constraint -- the
lack of basic data characterizing germination of tropical species at different
temperatures and water potentials. Though laboratory data collected in these
experiments are not exhaustive or extensive, they provide initial insight into species
characterization of selected under-researched tropical species for two of the three

key variables controlling germination response. Data demonstrate that under either

29
temperature or water stress, germination rate slows and/or final germination
percentage decreases for each of the eight species studied. These changes in
germination response are usually accompanied by increases in variance, which
generally occur before and during a large shift in the mean, and treatment variance
comparisons indicate when conditions for the germinating seed.

To summarize, these data successfully and rapidly characterize the eight
tropical species studied, over a wide range of temperatures and water potentials,
defining harsh to optimum conditions for each. So the method proved effective as
an initial characterization tool. The question remains, given prior knowledge of
macro-level temperature and water conditions at a field site, will it serve as an

effective screening procedure for field testing?

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Ashraf, CM. and S. Abu-Shakra. 1978. Wheat seed germination under low
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30

31

Ellis, R. H. and PD. Butcher. 1988. The effects of priming and natural differences in
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between water stress and the control of germination: a review. Plant, Cell and
Environment. 1: 101 -1 19.

32

Hegarty, T.W. and H.A. Ross. 1979. Effects of light and growth regulators on
germination and radicle growth of lettuce seeds hel under high-temperature
stress and water stress. New Phytol. 82: 49-57.

Heydecker, W. 1977. Stress and seed germination: en agronomic view. In A.A.
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41 3-41 9.

Kay, Daisy E. 1979. Food Legumes. Tropical Products Institute, London, 413 pp.

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33

Mayer, A.M. and A. Poljakoff-Mayber. 1975. The germination of seeds. Second
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Prokof'ev, A.A., N.V. Obrucheve, L.S. Kovadlo, L.K. Kulieve, and LS.
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34

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Thompson, P.A., S.A. Cox, and R.H. Sanderson. 1979. Characterization of the
germination responses to temperature of lettuce (Lactuca sativa L.) Achenes
Ann. Bot. 43: 319-334.

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Villiers, T.A. 1972. Seed dormancy. In T.T. Kozlowski, ed. Seed Biol. Vol. II:
Germination control, metabolism and pathology. New York and London,
Academic Press.

35

Table 1 . Selected species with potential as cover crops in harsh environments,
characterized in laboratory germination studies

 

Common Name (Variety)

Latin Name

 

Vegetable amaranth (Hijau)
Hierba more“

Jack bean

Tropical kudzu

Lableb bean

Lettuce (Grand Rapids)
Sunnhemp

Tepary bean

Tropical velvet been
Wheat (Frankenmuth)

Amaranthus cruen tes L.

Solanum americanum Miller

Canava/ia ensiformis IL.) DC

Pueraria phaseoloides

Lab/ab purpureus IL.) Sweet:
Dolichos Iablab

Lactuca sa tiva

Cro tolaria ochroleuca

Phaseolus acutifo/us A. Gray

Mucuna deeringia

Triticum aestivum

 

' Indigenous species collected from Dominican Republic field site

36

Table 2. Experimental conditions for germination We experiments,
water not limiting (w=near-seturation)

 

 

190'2909 ZQO'QQOQ 390'4909 3§o_4§og
Species S/R‘ C2 S/R C S/R C S/R C
Amaranth 50° P7 50" P 50° P 50° P
Hierba more 50 T° 50 T 50 T -° --°
Jack been 20 T 10 T 20 T 20 T
Tropical kudzu --‘ --‘ 100 P 50 T 50 T
Lableb been 50 P 50 T 50 T 50 T
Lettuce 50° P 50° P 50° P -° -°
Sunnhemp 50 T 50 T 50 T 50 T
Tepary been 50 T 50 T 50 T 50 T
Velvet bean 20° P 15° T 20° T 20° T
Wheat 505 P 505 P 505 P so5 P

 

1 Number of seeds per replication

2 Container in which germination experiment conducted; see notes 7 and 8

3 Seeds pre-chilled 3 days at 4°C on blotter paper moistened with 0.2% KNO;
solution to break dormancy

4 Seeds not available for this experiment

5 Seeds pre-chilled on damp blotter paper 3 days at 4°C to break dormancy

6 Seed coats knicked opposite hilum and micropyle to promote germination

7 P: sterile Petri dish

8 T = plexiglass tray

9 Not included in this experiment (failure to germinate at 30°-40°C temperatures)

37

Table 3. Experimental conditions for germination manual experiments,
temperature not limiting (20°-30°C)

 

Q Q Mpg -Q,§ MPa -1,Q MPa -] ,5 MPa

 

Species S/R1 C2 S/R C S/R C S/R C
Amaranth 50 P3 1 00 P 1 00 P 50 T
Hierba more 50 T‘ 100 T 50 P 50 T
Jack been 10 T 40 T 40 T 20 T
Tropical kudzu 1 00 P 50 T 50 T 50 T
Lableb been 50 T 40 T 50 P 50 T
Lettuce 50 P 50 T 50 T 50 T
Sunnhemp 50 T 50 T 50 T 50 T
Tepary bean 50° T 50 T 50 T 50 T
Velvet bean 15° T 50 T 20 T 50 T
Wheat 50 P 50 P 1 00 P 50 T

 

1 Seeds per replication

2 Container in which germination experiment conducted; see notes 3 and 4
3 P= sterile Petri dish

4 T = plexiglass tray

5 Seed coats knicked opposite hilum and micropyle to promote germination

38

Table 4. Seeds per replication by species for substrate experiment

 

Species N m r f r Ii i
Amaranth 50
Hierba more 50
Jack been 15
Tropical kudzu 50
Lableb been 25
Lettuce 50
Sunnhemp 50
Tepary been 50
Tropical velvet been 10

Wheat 50

 

39

Table 5. Reported and experimentally determined base temperatures for selected

 

 

 

 

species
Reported base Base temperatures
temperature assigned in this
Species (°C) Reference study (°C)
Amaranth 8 National Research 10
Council, 1984
8 Putnam, 1990
11.9 Angus et al., 1980/81a
Hierba mora -- 10'
Jack bean -- Kay, 1979: "does 14"
not tolerate frost"
Tropical kudzu 12.5 Skerman, 1977 16
Lableb been 3 Murtagh and 7
Dougherty, 1968
9.6 Angus et al., 1980/81a
Lettuce 2 Thompson et al., 19769 2
7,10 Thomas and Miller, 1979,
in Lawlor et al., 1990
Sorghum 10 Kanemasu et al., 10
1980/81a
Angus et al., 1980/81a
> 10 Singh and Dhaliwal, 1972
Sunnhemp -- 10 ' “
Tepary been > 8 Kay, 1979 8
8 Scully and Waines, 1988
Tropical velvet > 5 Kay, 1979 10
been >10 Skerman, 1977
Wheat 0 Gallagher, 1979 3
2 Del Pozo et al., 1987
2.6 Angus et al., 1980/81a
3.3-5.6 Nuttonson, 1955
5 Cudney et al., 1989
> 5 Singh and Dhaliwal, 1972

 

' Base temperature assigned arbitrarily, no existing data
* ' Base temperature assigned based on data collected in this study

40

Table 6. Seed moisture %: initial and final in W experiments (near-
saturation)

 

Moisture % at germination

 

 

 

 

 

Initial 1 0°-20°C 20°-30°C 30°-40°C

Mom

16 Std. Std. Std.
Species Mean Mean Dev. Mean Dev. Mean Dev.

%

Amaranth 9.5 35.1 15.9 24.5 8.5 76.5 29.2
Hierba more --‘ 16.5‘ 7.9‘ 49.9‘ 27.8‘ ---3 —-3
Jack been 18.2 129.4 7 1 117.4 13.3 141.6 11.8
Tropical kudzu 11.3 ---’ ---’ 128.9 5.7 143. 2 12.2
Lableb bean 12.4 96.5 10.9 88.5 10.0 116. 7 14. 8
Lettuce 2.8 61.3 18.3 70.1 40.3 ---° --°
Sunnhemp 11.6 129.4 18.1 98.7 23.4 127.1 9. 9
Tepary bean 11.8 100.6 5.9 95.9 5.3 111.2 7. 9
Velvet been 10.0 107.0 13.7 99.2 9.6 120.7 13.0
Wheat 10.1 58.3 4.7 77.9 12.9 55.7 19. 4

 

1 Sample size too small for reliable results
2 No seeds available for this experiment
3 No germination at this temperature

Table 7. Seed moisture %: initial and final in W experiments (20°-30°C

night-day temperatures)

41

 

Moisture % at germination

 

 

 

 

 

Initial 0.0 MPa -0.5 MPa -1.0 MPa

Moistute

_% Std. Std. Std.
Species Mean Mean Dev. Mean Dev. Mean Dev.

%

Amaranth 9.5 30.6 14.2 34.9 14.9 18.2 9.5
Hierba mora --‘ 49.9 27.81 62.2 17.31 --’ ---’
Jack bean 18.2 117.4 13.3 104.0 5.0 97.7 1.8
Tropical kudzu 11.3 128.9 5.7 102.0 21.5 98.3 17.6
Lableb been 12.4 88.5 10.0 110.2 11.4 103.6 5.7
Lettuce 2.8 70.1 40.3 47.6 28.3 ---2 ---’
Sunnhemp 11.6 98.7 23.4 133.3 23.8 122.6 17.0
Tepary been 11.8 95.9 5.3 118.0 9.7 113.6 4.8
Velvet bean 10.0 99.2 9.6 105.3 7.7 --’ ---’
Wheat 10.1 51.5 16.9 39.4 6.6 46.3 8.0

 

1 Sample size too small for reliable results
2 No germination at this water potential

42

Table 8. Maximum germination percent as affected by substrate medium in growth
chamber experiments (20°-30°C, near-saturation water potential)

 

Maximum germinatign percent

Species 31mm 5.911 L512
Vegetable amaranth 98.0 86.5 NS‘
Hierba more 97.0 59.5 NS
Jack bean 95.0 92.0 NS
Tropical kudzu 49.5 23.0 9.9 ' *
Lableb bean 57.5 45.0 NS
Lettuce 33.0 92.0 23.0' '
Sunnhemp 89.0 81.5 NS
Tepary bean 93.5 68.5 19.6'
Tropical velvet been 71.5 65.0 NS
Wheat 99.0 89.5 NS

 

1 Not significant at LSD = 0.05

" Significant at LSD= 0.05
” Significant at LSD = 0.01

43

 

 

 

 

 

 

 

7o - Jack Bean
8
° 60 - - -
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Mean Daily Temperature (°C)

Figure 1. Germination rate by temperature for jack been with base temperature
estimated from x-Intercept

 

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substrate and soil substrate

CHAPTER 2

FIELD GERMINATION RESPONSE OF SEVEN TROPICAL

SPECIES OF VEGETATIVE COVER

INTRODUCTION

The majority of seed germination studies have been conducted in laboratories
with temperate species under highly controlled, and often moderate, conditions of
light, temperature and water (Khan, 1977). Many fewer studies have been
conducted under field conditions where multiple detrimental environmental factors
decrease rates and final germination percentages. These factors include too little or
too much light/water, suboptimal or supraoptimal temperatures, limiting soil fertility
or soil physical structure, pathogens, harmful microbial activity, and predacious
birds, insects and rodents (Khan, 1977; Roundy et al., 1985).

Low water potential alone directly inhibits seed germination in the field.
Indirectly, low soil matric potential decreases soil hydraulic conductivity and water
movement to the seed, decreasing seed imbibition (Hadas, 1982; Hadas and Russo,
1974a; Hades and Russo, 1974b). This can cause lower field germination rates for
some species under identical field and laboratory matric potentials (Roundy et al.,
1985); though Hades (1977) found good germination correspondence from lab to
field matric potentials for chickpea, sorghum and vetch.

The relationship between germination and soil matric potential is not simple,

56

57
especially when seeds are placed at the soil surface. Seed size, rate and amount of
seed swelling during imbibition, nature of seed surface and seed mucilage content
all influence seed-soil—water contact area and eventual germination in the field and
Black, 1983). In an early study, Swanson and Hunter (1936) compared lab and
field germination of 17 sorghum varieties. Mean lab germination was 95%, and
mean field germination was 50%, with a range of 30 to 50% reduction in field
germination.

Still remaining within the confines of the traditional approach to agronomic
research (Chapter 1), this study goes one step beyond laboratory germination
research and addresses an important hypothesis regarding seed germination in the
field - that boundary conditions for germination established in growth chamber
experiments are useful in predicting performance in high stess environments
occurring in the field. Therefore, the objective of this study was to field test
surface germination and early growth of seven tropical species with potential for
use as vegetative cover crops at a specific tropical field site. Field data are
compared to previously collected laboratory data (Chapter 1) to ascertain the

effectiveness of lab data in predicting field germination response.

MATERIALS AND METHODS
Introduction
Between 1990 and 1993, a series of initial exploratory (data not reported) and
then full-scale field seed germination experiments were conducted in the village of
Buen Hombre in the Dominican Republic, which shares the Caribbean island of

Hispaniola with Haiti to its west. Hispaniola lies east of Cuba and west of Puerto

58
Rico. Buen Hombre is located on the northwest coast of the Dominican Republic,
near the Haitian border at approximately 19° 51' N latitude and 71° 24' W

longfiude.

Characterization of Soil Resources and Weather

Soil resources and weather conditions were characterized prior to the initiation
of field experiments. Soil resources in Buen Hombre were characterized in a non-
traditional way, based on methods suggested by Pawluk et al. (1992). No detailed
information exists for soils of Buen Hombre, or in fact for many soils in the
Dominican Republic. Local research institutions generally have not existed long
enough, or lack the time and money, to collect and interpret soil data. However,
Pawluk et al. (1992) recommend that in developing countries where little previous
data exist, soil scientists should work with farmers to identify general soil types of
importance to local agriculture and then locate typical examples of each type. Data
collection efforts are then focused only on soils of local importance. This technique
seemed appropriate and was used in Buen Hombre. Farmers described three
general soil types, "black,” "yellow," and ”mixed."

Accordingly, soil profile pits were dug in the black and yellow soils at valley and
hill slope locations, respectively, designated as being representative locations for
these two soils by the current president of the farmer's association. Horizon depths
were measured and characterized as to soil color, soil structure and soil texture,
which was determined from soil samples taken from each horizon, using the
Bouyoucos hydrometer method (Gee and Bauder. 1986). Soils were classified into

taxonomic subgroups using standard criteria (Soil Survey Staff, 1990).

59

Soil fertility tests were performed on what villagers defined as the three main
soil types of Buen Hombre -- ”black," ”yellow," and "mixed” -- to verify villagers'
descriptions of relative soil fertility. Composite surface (0 to 7.6 cm) soil samples
were collected from forty locations in each of three fields, designated as having soil
that was representative of one of the three soil types by the president of the
farmer's association. Samples were thoroughly mixed, subsampled, air-dried in the
village (relative humidity of 65 to 75%), air-dried again under laboratory conditions
(27% relative humidity) and sieved through a 6.25 mm screen. Soil fertility tests
were performed at the Michigan State University soil testing laboratory, using
Olsen’s sodium bicarbonate extraction for available phosphorus, ammonium acetate
extraction for potassium, calcium and magnesium and ammonium bicarbonate-DTPA
extractable for manganese, zinc, copper and iron (Council on Soil Testing and Plant
Analysis, 1980).

8qu densities were determined on intact soil cores (7.6 cm in diameter, 7.6 cm
in length) sampled in quadruplicate at depths of O-7.6 cm and 7.6-15.2 cm for the
black soil only. Bulk density was determined on a mass per volume basis after
oven-drying cores for 48 hours at 105°C in a forced air oven (Blake and Hartge,

1 986).

Weather data were obtained from a centrally located LICOR data logger, which
operated between 1990 and 1993 for separate 3- or 4- week periods in January,
1991; February, 1991; March, 1991; March, 1992; April, 1991; April, 1992 and a
15-week period from July to October, 1991. The data logger recorded mean hourly
temperature at one meter above the soil surface, mean hourly surface soil

temperature at 2.5 cm beneath the soil surface and mean solar radiation every 15

60
minutes in Watts m’. Precipitation was measured manually with a rain gauge at the
center of the village. Relative humidity was measured twice daily with a sling

psychrometer at 7:00 am. and 4:00 pm.

Seed germination experiments

Experimental field plots were centrally located in the valley on the black soil
designated by villagers as being representative of other black soils in the village.
Plots were prepared by clearing weeds and plant debris from the surface with
machetes, clearing rocks away, manually cultivating the top 5 cm of soil and
constructing small bordered plots 50.8 x 101.6 cm with a 7.6 cm embankment on
all four sides to concentrate and control water applications. The entire plot area
was fenced and gated with posts and barbed wire to provide further control and
protection against intrusions by cattle, goats and curious children (Figure 1).

Full-scale germination field experiments were conducted in March and April,
1992, to investigate germination response at the end of the rainy season, and in
September and October, 1991, to follow germination response at the end of the dry
season. Seeds were planted at the soil surface in evenly spaced rows, and a
colored plastic toothpick was inserted in the soil adjacent to each seed to mark its
location. Seeds selected for planting were not visibly damaged and were selected
without regard to size or color. Species planted and number of seeds per replication
for both the March-April and September-October studies are listed in Table 2. Plots
were hand-watered daily with 4 L per plot, using water transported by burro from
the Buen Hombre well (Figure 1).

Visible, ungerminated seeds remaining at the surface were counted daily, as

61
were germinated seeds. Seeds were not removed upon germination, and seedlings
were monitored for height, leaf number and extent of insect damage throughout the
experiment. Weed seedlings were counted daily in the September-October, 1991,
experiment. The duration of the March-April experiment was 19 days. The

September-October experiment lasted 24 days.

Species Selection

Plant species (Table 1) selected for inclusion in the field experiments did not
overlap entirely with those tested in laboratory experiments (Chapter 1). Seed
propagation plots at a research institute in Santiago failed due to irrigation pump
failure. Therefore, some species used in the laboratory experiments were not
available for field testing. An indigenous species, Hierba Amarga (Parthenium
hysterophorus L.), did not germinate in lab or field experiments. Also, a bird-
resistant sorghum variety was field tested, but was unavailable for laboratory

experiments.

Use of thermal time
Germination data are reported in thermal time (Ritchie and NeSmith, 1991), or
accumulated temperature, for ease of comparison to laboratory data, using the
formula for thermal time in growing degree days, or °Cd (Ritchie and NeSmith,
1991k
°Cd= {Wm-Tb...) [1]

Base temperatures used were those defined in Chapter 1.

62
Statistical design and analyses
Field experiments were conducted as a randomized complete block design with
four replications of each species separated in time. Analyses of variance were
performed on all data. There were highly significant differences between species
and between times in all these experiments and oftten between time by species, as

well.

RESULTS AND DISCUSSION

l. Agricultural Context: Soil Resources and Weather

Buen Hombre soils (”black,” “yellow” and "mixed') are all reported to be
productive for a wide variety of crops, when there is rain. Black soils tend to be
clustered in the valley, while yellow soils are generally located on mountain and hill
slopes. Table 3 shows soil profile characterization for both soils, and Table 4 lists
taxonomic descriptions. Buen Hombre soils are calcareous mollisols (developed
soils with high pH) or entisols (soils with an ochric epipedon and little development
of subsurface horizons). The semi-arid climate greatly slows soil development. Soil
texture is coarse at the lower horizons of all three black profiles (gravelly sand,
sandy gravel). The upper horizons are fine- and moderate-textured (sandy loam,
loam, silt loam and clay loam), but tend to be rocky at the surface. There is some
surface crusting and cracking under repeated high intensity watering.

Soil fertility tests validate farmers' reports of productive soils. Soils are
moderately fertile and high in pH (Table 5). Both black and yellow soils have high
potassium levels and soil phosphorus levels above 24 kg ha“, which is the level at

which there is no crap response to additions of fertilizer phosphorus (Council on Soil

63
Testing and Plant Analysis, 1980). Manganese and copper levels are adequate.
Cation exchange capacity is high, indicating the soil's ability to retain nutrients for
plant growth. However, soils with free calcium carbonate in the top 50 cm and pH
values above 7.3, like those in Buen Hombre, ”are often deficient in micro-nutrients,
particularly Fe and Zn" (Sanchez and Logan, 1992). Zinc levels are low in these
Buen Hombre soils, though iron levels are adequate. Mean bulk densities for the
black soil are 1.04 Mg m‘3 at a depth of 0-7.6 cm and 1.06 Mg m” at 7.6-15.2 cm.
These are relatively low bulk density values, indicating the likelihood of ample pore
space for aeration and root growth near the surface. In conclusion, soil fertility and
soil physical properties for the soils tested do not appear to be limiting for
agriculture.

Historical accounts (Halmo et al., 1991) and records (Portman et al., 1991)
report average rainfall between 600 and 700 mm annually. Temperatures in the
village range from 19 to 33°C, with relative humidity generally between 60 and
70%. Figure 1a shows mean daily soil and air temperatures for a 4-week period
from mid-March to mid-April, 1992. March and April are at the end of the rainy
season, when vegetative cover of drought tolerant species would be planted so that
germination and initial root growth could take place while there was still rainfall.
Species planted in March and April could provide food during the dry season and
could provide ground cover for erosion protection at the beginning of the rainy
season.

Figure 2b shows temperature data for a 4-week period from mid-September to
mid-October, 1991, at the end of the dry season. Mean daily air temperature for

March and April is 261°C :1: 1.6°C, and mean daily soil temperature is 283°C :2

64
1.8°C. Mean daily air temperature for September and October is 29.0°C :l: 1.7°C;
mean daily soil temperature is 28.1 °C :l: 0.9°C. For thermal time calculations, a
mean daily temperature of 27°C was used for March-April data and 28.5°C was
used for September-October data. Mean solar radiation for both experiments,
calculated every 15 minutes over a 4-week period from mid-month to mid-month,
resulted in similar diurnal solar radiation cycles and variance in data for March-April

and September-October (Figure 3).

ll. Field Germination Response and Comparison to Laboratory Data
Field germination response of benchmark species: lettuce and wheat

Lettuce did not germinate in field experiments, as temperatures were too high
for this cold—season species. Field germination data of wheat on a surface area
basis shows the number of visible, but as yet ungerminated seeds per square meter
of soil surface, as well as the number of visible, germinated seeds at the surface for
March-April (Figure 4a) and for September-October (Figure 4b). Figures 4a and 4b
each have a variance graph beneath, showing standard error values corresponding
to each data point in the corresponding graph above. In Figure 4a, the number of
ungerminated seeds at 0°Cd thermal time reflects seed density at planting, which
decreases prior to germination as seeds fall into cracks, subside into soil with
watering, are eaten by birds and insects, etc. The lines in Figure 4a representing
germinated and ungerminated seeds cross when ungerminated seeds below the
surface disappear from view and later germinate.

Wheat reached 90 germinated seeds In2 in March-April, with almost no

germination in September-October. Wheat plots were attractive to ants, and many

65
seeds were lost to ant predation. The first insect damage to seedlings was noted
on day 11. Seedlings that survived insect damage in March-April grew to 16.0 cm
and appeared robust. September-October seedlings were spindly and weak by the
close of the experiment. Although it will be discussed more thoroughly later in this
chapter, March-April wheat germination in the field in the tropics is reduced 57.5%
from growth chamber germination, though rates are similar when germination is

carried out on the field site soil in a growth chamber.

Field germination response of tropical species

Hierba amarga, the species indigenous to Buen Hombre, and tropical kudzu did
not germinate in the field in either March-April or September-October. In the March-
April study, a rapid initial decrease in visible Iablab seeds at the surface was the
result of seeds falling into cracks and subsiding into the soil with watering (Figure
5a). Germination was much lower at the end of the dry season (Figure 5b), never
reaching 20 seeds m”, than it was at the end of the rainy season (Figure 5a), when
maximum levels reached 50 germinated seeds m". Figure 5b includes number of
weeds per square meter as a simple indicator of competition from indigenous
species. As in Figures 6b to 9b, weed growth increases with time in all the
September-October experiments. Germinated Iablab seeds were not affected by
insect damage until seedlings reached a mean height of 5.8 cm. As seedlings
increased in size, insect damage also increased.

Bird-resistant sorghum plots had high weed populations, and sorghum
germinated poorly in both field experiments (Figure 6). Original planting density

was 297 seeds m'2 in March-April and 77 seeds m" in September-October.

66
Ungerminated seeds were too small for easy visibility at the surface and thus were
not plotted in the figures. Sorghum plots were the subject of much ant activity, and
many sorghum seeds were eaten shortly after planting. Of the sorghum that did
germinate, insect damage was not noted until nine days after planting.

Sunnhemp also germinated better in March-April, reaching a maximum density
of 124 germinated seeds m", compared to 43.5 seeds m" in September-October
(Figure 7). Visible seeds at the surface decreased rapidly, and the earliest
germinators germinated from surface cracks. Ants ate sunnhemp seeds. but not to
the same extent as sorghum. As early as day 5 post-planting, insect damage to
seedlings had begun. Seedlings were subjected to several kinds of insect damage,
including decapitation of main stem and top leaves, deformity and yellowing of
leaves and "excavation” of the top palisade leaf layer. Goats also dug under barbed
wire fencing to eat sunnhemp seedlings.

Velvet been reached maximum germination of 96 seeds In2 in March-April, with
almost no germination at the end of the dry season (Figure 8). Seeds rapidly
subsided into the surface with watering, but remained visible, and seed coats turned
black. The earliest germinators were those that had fallen into small crevices at the
soil surface. Some seeds were eaten at the soil surface prior to germination.
Earliest insect damage occurred at day 8, ultimately killing all seedlings through
decapitation of stem and leaves, leaf curling, leaf holes and leaf blackening. Also,

local goats were fond of young velvet bean plants.

Weed competition and insect damage in field experiments

It is interesting to note that indigenous weed species growing in microplots

67
were also damaged by insects. It is clear from these experiments that once water is
no longer limiting, biological activity in the form of bird, insect and goat predation is
the single greatest limitation to success of surface germination and seedling survival
at this tropical field site at this time of year (September-October), when there is
very little else growing. Though insecticides could have been applied in the
experiments, it is not realistic to expect villagers to buy insecticides for cover crops
during large-scale field implementation. Therefore, they were not used here.

Hand broadcast seeds that remain at the surface until germination are those
shunned by ants and birds, or those that subside quickly, such as velvet bean
(Figure 10). In harsh subsistence environments like Buen Hombre, broadcasting at
the surface appears to put seeds at too great a risk for successful establishment.
Hand broadcast seeds may need to be selected based on their ability to germinate
quickly, subside or fall into cracks quickly, or seeds may need to be trampled into
the soil at planting. In March-April, several species originally planted at a rate of 50
per microplot were replanted at a rate of 100 per plot in order to get successful
germination. Thus, another management strategy to deal with tropical biological
activity is overseeding. Dark seeds, such as sunnhemp, may have an advantage in
surface seeding, if dark soil acts as camouflage protecting them from birds and
goats. Hand broadcasting may be an inappropriate management technique for
tropical environments, but insect damage to seedlings after germination can be just

as severe as seed loss at the surface from predation prior to germination.

Reporting of laboratory vs field germination data

Laboratory germination data were reported in Chapter 1 as cumulative

68
germination percent. Figure 1 1 shows field data for tropical velvet been, reported
both as cumulative germination percent and the actual germination percent of still
visible seedlings recorded in the field each day. A key issue in field germination,
where water, temperature and light are not limiting, is post-germination senescence
due to insect, pathogen or predatory damage. It is clear from Figure 11 that
reporting field data as cumulative germination percent obscures information about
day-to-day attrition of seedlings. For this reason, actual germination percent is the

format used to present field data in Figures 12 to 17.

Field data as actual germination percent

Wheat has low germination in March-April (Figure 123) and lower germination in
September-October (Figure 12b), but seedlings persist. Lablab (Figure 13) has low
germination, but ungerminated seeds persist relatively well at the surface. On a
density basis, more Iablab seeds germinated in March-April (Figure 5a) than
September-October (Figure 5b). But as a proportion of initial seeds planted, Iablab
germinates at a maximum 26% in September-October, compared to 20% in March-
April. Sorghum (Figure 14) germinates poorly in both experiments. All other
species perform better at the end of the rainy season (Figures 15 to 17), and tepary

has a slower rate of seed loss in September-October.

Comparison of field and laboratory data
Maximum cumulative germination percent in the laboratory on blotter paper at
mean daily temperatures of 25°C under near-saturation water conditions is

compared to cumulative germination percent of field data at mean daily

69

temperatures of 27°C, with daily watering (Table 6). These data show similar
thermal times to maximum germination for Iablab. Though thermal time a];
maximum cumulative germination percent is greater for sunnhemp and tepary in
laboratory experiments, these species first reach near-maximum germination
percents of 87.0% (sunnhemp) and 88.5% (tepary) at 120°Cd (sunnhemp) and
119°Cd (tepary) (data not shown), which is very similar to field thermal time data
for maximum cumulative germination percent in Table 6. Velvet bean and wheat
show greatly delayed germination rates in the field, compared to laboratory results.
And all species show reduced maximum germination percent in the field.

However, soil taken from the field test site and used to replace blotter paper as
a substrate, reduces laboratory germination. Therefore a more realistic comparison
between field and laboratory data is one in which laboratory experiments are
conducted on field site soil as the germination medium. When such a comparison is
made (using soil substrate), maximum germination percent is reduced 19 to 57.5%
from laboratory to field, depending on the species (Table 7), as compared to
reductions ranging from 31.5 to 63.5% from laboratory (using blotter paper
substrate) to field (Table 6). Though further testing is needed to ascertain whether
the species-specific reduction factor (rightmost column, Table 7) is relatively
consistent from year to year, lab data in this study provides useful information
about field germination and early growth response under limiting conditions.

For the benchmark species, laboratory data predicted lettuce would probably not
germinate under field conditions unless mean daily temperatures remained at or
below 25°C, but that wheat would germinate. Also from laboratory data, one

would have expected amaranth and tropical kudzu to do well in the field under Buen

70
Hombre weather conditions. Yet they did not germinate at all, due perhaps to harsh
physical conditions at the surface or surface exposure to birds and insects. For jack
bean, Iablab, sunnhemp, tepary and velvet bean, laboratory data accurately
predicted success in the field, though jack bean could not be included in full-scale

testing, due to lack of seed availability.

CONCLUSIONS

Boundary conditions for germination, established in growth chamber
experiments, can in fact be used to predict germination in high stress field
environments. Whether the specific reductions in final germination percent from lab
to field (in this case, reductions of 19% for Iablab, 44% for sunnhemp, 24% for
tepary and 32% for tropical velvet bean) are relatively consistent from year to year
remains to be tested. What is clear is that based on laboratory characterization
studies (Chpater 1), successful germination performance was predicted for the field
for all but two species. Based on these data and data for jack been from a
preliminary field study, the next step would be field trials of jack bean, Iablab bean,
bird-resistant sorghum, sunnhemp, tepary bean and tropical velvet been for an
entire dry season. Objectives would be to monitor crop response to physical
conditions at the site beginning in May, ascertain whether biotic interactions are
reduced with large plots or are confined to edges and monitor labor and economic
factors, as well as villager reponse to cover crops at several levels (adoption, use,

management, incorporation into diets, etc.).

LIST OF REFERENCES

Bewley, J. Derek and Michael Black. 1994. Seeds: Physiology of Development and
Germination, Second Edition. Plenum Press, New York and London.

Blake, G.R. and K.H. Hartge. 1986. Bulk density. In: Klute, A. (Editor), Methods of
Soil Analysis, Part 1. Physical and Mineralogical Methods - Agronomy
Monograph no. 9 (second edition). American Society of Agronomy, Soil Science
Society of America, Madison, Wisconsin, 1 18 pp.

Council on Soil Testing and Plant Analysis. 1980. Handbook on Reference Methods
for Soil Testing (revised edition). University of Georgia, Athens, Georgia, 130
Pp-

Gee, G.W. and J.W. Bauder. 1986. Particle-size analysis. In: Klute, Arnold (Editor),
Methods of Soil Analysis, Part 1. Physical and Mineralogical Methods -
Agronomy Monograph no. 9 (second edition). American Society of Agronomy,
Soil Science Society of America, Madison, Wisconsin, 1 18 pp.

Hades, A. and D. Russo. 1974a. Water uptake by seeds as affected by water
stress, capillary conductivity and seed-soil water contact. I. Experimental study.
Agron. J. 66: 643-647.

Hades, A. and D. Russo. 1974b. Water uptake by seeds as affected by water
stress, capillary conductivity and seed-soil water contact. II. Analysis of
experimental data. Agron. J. 66: 647-652.

Halmo, David, Andrew Williams, C. Gaye Burpee and Brent Stoffle. 1991.
Ethnohistory of Buen Hombre. In: Richard W. Stoffle and David B. Halmo
(Editors), Satellite Monitoring of Coastal Marine Ecosystems: A Case from the
Dominican Republic. CIESIN (Consortium for International Earth Science and
Information Network), Saginaw, Michigan. pp. 74—92.

Khan, Anwar A. 1977. Preconditioning, germination and performance of seeds. In
A.A. Khan, (Editor). The Physiology and Biochemistry of Seed Dormancy and
Germination. North Holland Publishing Co., Amsterdam.

Pawluk, Roman R., Jonathan A. Sender, and Joseph A. Tabor. 1992. The role of

indigenous soil knowledge in agricultural development. J. Soil Water
Conservation 47(4): 298-302.

71

72

Portmen, Donald, David Wilson, and William Kuhn. 1991. Climate history of Buen
Hombre. In: Richard W. Stoffle and David B. Halmo (Editors), Satellite
Monitoring of Coastal Marine Ecosystems: A Case from the Dominican Republic.
CIESIN (Consortium for International Earth Science and Information Network,
Saginaw, Michigan, 269 pp.

Roundy, Bruce A., James A. Young and Raymond A. Evans. 1985. Germination of
basin wildrye and tall wheatgrass in relation to osmotic and matric potential.
Agron. J. 77:129-135.

Sanchez, Pedro A. and Terry J. Logan. 1992. Myths and science about the
chemistry and fertility of soils in the tropics. In: R. Lal and P.A. Sanchez
(Editors), Myths and Science of Soils in the Tropics, SSSA Special Publication
Number 29. Soil Science Society of America, Inc., Madison, Wisconsin, pp. 35-
46.

Soil Survey Staff. 1990. Keys to Soil Taxonomy, fourth edition. SMSS technical
monograph no. 6, Blecksburg, Virginia, 422 pp.

Swanson, A.F. and Robert Hunter. 1936. Effect of germination and seed size on
sorghum stands. Agron. J. 28:997-1004.

73

Table 1 . Selected species with potential as cover crops in harsh environments,
characterized in field germination studies

 

Common Name (Variety)

Latin Name

 

Vegetable amaranth (Hijau)
Hierba amarga'

Tropical kudzu

Lablab bean

Lettuce (Grand Rapids)
Bird-resistant sorghum
Sunnhemp

Tepary bean

Tropical velvet been
Wheat (Frankenmuth)

Amaranthus cruen tes L.

Parthenium hysterophorus L.

Pueraria phaseoloides

Lablab purpureus IL.) Sweet:
Dolichos Iablab

Lac tuca sa tiva

Sorghum bicolor

Cro to/aria ochre/euca

Phaseolus acutifolus A. Gray

Mucuna deeringia

Triticum aestivum

 

" Indigenous species collected from Dominican Republic field site

74

Table 2. Buen Hombre field experiments: species and number of seeds per
replication

 

 

M r h - il $291M
Number of seeds Number of seeds
Species per replication per replication
Hierba emerge 25 50
Tropical kudzu 25 -‘
Lableb been 25 40
Lettuce 50 50
Sorghum 25 100
Sunnhemp 50 100
Tepary been 50 100
Velvet been 25 100
Wheat 50 100

 

1 Species not tested in this experiment

75

Table 3. Soil profiles of "black” and ”yellow” soils, Buen Hombre

 

Buen Hombre "black" valley soil

 

 

 

Structure

Horizon Depth (cm) Texture Color Shape Grade
Ap 0-18 Clay Loam 10YR 3/3 SAB Mod
A 18-36 Clay Loam 10YR 5/3 AB Mod
E 36-53 Loam 10YR 6/2 SAB Mod
B 53-70 Clay Loam 10YR 4/3 SAB Mod
C 70-99 Extremely ......" m --

cobbly sand

and gravel
2Cbk 99-132 Clay Loam 10YR 4/3 SAB Mod

 

119mg: Heploxeroll; 0% slope; solum = 53 cm; 8.0 pH for Ap horizon;
effervescence for all horizons with 1.0 N HCI, no effervescence with 0.1 N HCI

 

Buen Hombre “yellow“ hill soil

 

 

 

Structure
Horizon Depth (cm) Texture Color Shape Grade
A1 0-9 Loam 2.5Y 4/4 SAB Mod
A2 9-20 Loam 2.5Y 3/2 SAB Mod
Bw 20-44 Silt Loam 2.5Y 4/3 SAB Mod
C 44+ Silty Clay 2.5Y 5/4 Plety Mod

Loam

 

1101953 Torriorthent; 7% slope; solum =44 cm; 7.8 pH for A1 horizon;
effervescence for all horizons with 1.0 N HCI, no effervescence with 0.1 N
HCI

76

 

«005.0...0h
0.8.05.00800.
0008.00.00.
00.08 0080800..
.95 >800_-00....

0005.080...
28.05.0083.
0000.00.00.
00.08 00000800..
.0>0 >800_-00.000

__0.0x0_00.._
0.8.05.00800.
0000.00.00.
00.08 00000800..
.0>0 >800_-00.u_

__0.0x0.00I
08.05.002.00.
000080200. 00.08 $800..

0.0.0.08 _.00 0.0.3 0
00.30.0082 8.0.5 0

000800.080 00800
05.. ._.00 0000.» >.0> e
.0055 e

0.00.08 _.00 0.0.2 0
00.30.0083 802, e
808020.60 000.00

050.. ...00 0000.» >0) e
8055 0

00.0.0 0000 00.: 0

00.20.0083 8.0>> 0
80802080

0080: e

.0052). 0

00.00 0000 00.: 0

00.30.0082 802. e
500802050

000.0... 0

_00_=0_2 e

=8
82...... 25...; ”3.0.0

_.00 >0_.0>
x00_0 500880550.
005083 .0300 "aimed

_.00 >0=0> 5.00.0
600820.22 "a

_.00 >0=0>
v.00_0 00008805000.

00.00>0.0 .000... ... _..aw

 

0800 3.80..

005000008000 >3.

_.om

 

0.0801 000m .260 26:0.» 000 0.00.0 .0 005000.0006 .0 0.00 .r

77

Table 5. Soil fertility of the three major Buen Hombre soil types, as designated by
farmers

 

 

 

 

 

 

Soil test ”Black” "Yellow" ”Mixed"
Soil Soil Soil

Soil pH 7.6 8.1 8.0
Cation exchange capacity 39 32 41

(cmols (NH,+) kg" soil)

MACRONUTRIENTS
Olsen phosphorus (kg ha") 30 25 20
Potassium (kg ha") 1,664 1,375 637
Calcium (kg ha") 15,279 12,167 15,845
Magnesium (kg ha") 780 1,295 1,344

MICRONUTRIENTS
Zinc (mg kg") 0.7 0.7 0.5
Manganese (mg kg") 46.4 14.4 12
Copper (mg kg") 1.7 0.6 7.4
Iron (mg kg") 7.5 6.5 7
Nitrate-N (mg kg") 12.9 3.5 8.2

 

78

0.0080098 0.0.. .0 0000.000. 00 .000 00.=.00.0.0 00. .0002, 00.00.00.000 .0. 0.0 0.00 0
0000.00 00000.8.00 050.0800 808088 0. 000000. 0.0 0000 0.0.“. N
.0000000 .0003 00.00.300.000 .0 0000800000 80200.0 0.00-00 .0. 0.0 0.00 380.000.. F

 

 

 

 

 

0.0 0.00 0 .0 0... 0.00 0: 080.5
0000

0.0 0.00 000 0.0. 0. K 00 . 82.5 .800...

0.0 0.0.. 00. 0.0 0.00 .0. :80 .080»

0.0 0.00 0 . . 0.0 0.00 00 F 052.550

0.0 0.00 00. 0.0 0.00 00. :80 0203
:00: :00: :60.-- I..... :00: :60.--

00.00300 00008800 08.. 00.00300 00008800 08.. 00.000m
0.000000 050.0800 .0800 .0 0.00005 02.05800 .0800...

80808.2 808.x0.2
.20.. 3.220000

 

0000 8000.002 000 0.0.. .0 000000800 0 00008800 050.0800 80806.2 .0 0.00...

79

Table 7. Maximum cumulative germination, a comparison of laboratory experiments
using Buen Hombre soil medium to field experiments in Buen Hombre

 

Maximum cumulative germination

 

 

 

 

Laboratory, Field, Lab
Buen Hombre Standard Buen Standard minus
Species soil deviation Hombre deviation field
%
Lablab bean 45.0 1 1.1 26.0 3.0 19.0
Sunnhemp 81.5 13.7 38.0 3.0 43.5
Tepary bean 68.5 11.3 45.0 6.8 23.5
Tropical 65.0 1 1.2 33.0 2.3 32.0
velvet bean
Wheat 89.5 9.6 32.0 6.4 57.5

 

8O

 

 

Figure 1 . Photographs of: (top) experimental field plots. Buen Hombre. Dominican
Republic, and (bottom) M. Perez, watering one microplot

Mean Temperature (°C)

Mean Temperature (°C)

Figure 2. Average daily surface soil and air temperatures. Buen Hombre: a) March-

81

 

42‘-
40‘-
38‘-
36‘-
34‘-
32‘-
30‘-
28‘-

March - April
Buen Hombre

A

I

 

26
24
22‘-

 

 

 

+ Air Temperature

 

l I ._
my + Soil Temperature

 

42‘-
40'-
38‘-
36'-
34--
32‘-
30 -

September - October
Buen Hombre

 

28 -

b

 

 

M, * + Soil Temperature

+ Air Temperature

 

 

 

 

‘I I I I I
0 4 8 12 16 20

Time (hours)

April, 1992 b) September-October, 1991

 

1200
I
8 1000-
3 900-
(U
E 800-
5 700-
:0
.92 600-
'3
m 500-
5 400-
0
a) 300-
5 200
Q)
5 100-
- o
“.‘
E
g 200-
‘3“
>' 100-
0
a
:9}
m 0
o

82

 

Buen Hombre

+ March - April
—0— September - October

 

 

 

 

 

 

 

ll
2 4 6 81012141618202224

Time (hours)

Figure 3. Mean solar radiation. Buen Hombre: March-April. 1992. and September-_
October. 1 991

83

 

 

35° ‘ Wheat a
300 { (Mar-Apr)
“-' 250 — \
. zoo - \ + Germinated
I Z 150 _ \ —l— Ungerminated

 

 

 

 

 

 

 

Wheat b
(Sept-Oct)

 

'2 150 ‘ + Germinated

 

 

 

 

 

 

 

m of F [W.—

O 50 100 150 200 250 300 350 400
Thermal Time (°Cd)

Figure 4. Mean density (N) and standard deviation is) of germinated and
ungerminated whaat seeds in the field: a) March-April and bl September-October

 

 

84

 

 

 

 

 

 

 

 

 

 

 

 

 

 

120 J a
-. Lablab
100 - l (Mar-Apr)
E 80 " -
' 60 -
Iz "
1 .0—4 0
4o - '2’ V"
20 _ + Germinated
i.// --I-- Ungerminated
NA 0 q—oo—o—o
I 15 l l l l l l l l l l
E 10 .I. .
E 5 ,' -. [\A‘Afl"
m 0 +83
120 - b
Lablab
100 - (Sept-Oct)
N 80 .I.. + Germinated
_ 60 - --I-- Ungerminated
'2 _ —-b-- Weeds /
40 ‘. /A
20 Ill" '14”.
' 000’ kt. ------ I-I .....
/; ...—_ I I". ":
NA 0 4”
, 15 I I I T I I I I I I
10
E5 8 “Hrs-44:. 1:344".—

 

 

ID I I I I r I I I I I I
0 50 100 150 200 250 300 350 400 450 500

Thermal Time (°Cd)

Figure 5. Mean density (N) and standard deviation is) of weeds and germinated and
ungerminated Jada; seeds in the field: a) March-April and bi September-October

85

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100 -
Sorghum a
0'1 30 .. (Mar-Apr)
E
' 60-
lz
4O -
+ Germinated
20 -
A 0 *4.” .‘.‘.- ’F—+.
6" 20 I l I l l l l
E: 10
‘0), O _...o—o..3-~o—o—-’——+’
100 -
Sorghum b
80 - (Sept-Oct)
‘7‘ .I"
8 60 - .I """ '
_ .-
z .- "
40 - I..-'1‘ —o— Germinated
.' --I-- Weeds
20 - ,'
.I
N
.520 I l ....Il"-..ll'"”.!' ----- [mu-E
at10 ......
v 0 -—-—'--'-——-O—0—0—0-0-0—0—0—o-0——0—H—.
in F 1 I I I I I I

0 50 100 150 200 250 300 350 400

Thermal Time (°Cd)

Figure 6. Mean density (N) and standard deviation (8) of weeds and germinated and

ungerminated WM seeds in the field: al March-April and bl
September-October

86

 

 

300 _~ Sunnhemp a
'. (Mar-Apr)
250 - ,
.E '- + Germinated

I - Ungerminated

 

 

 

 

 

 

 

 

 

 

 

 

r r l l
300 _ Sunnhemp b
(Sept-Oct)
N 250 '-
- + Germinated
_E 200 ' --I-- Ungerminated
'21504 -Ir--Weeds
100'- H.A.—_..;
5° ‘ Ml.“
.//-:‘ 1. '~

 

 

 

E 33 -....-
a. 0 turn-t“..-
0 50 100 150 200 250 300 350 400 450 500
Thermal Time (°Cd)

Figure 7. Mean density (N) and standard deviation is) of weeds and germinated and
ungerminated m seeds in the field: a) March-April and b) September-
October

87

 

 

 

 

240 j ' "-0 Tepary
N 200 ... . (Mar'APr) + Germinated
IE 0 I - Ungerminated
16 - ~
I -—-—0—0—-0.\
1 ..... . \0..
fl ' u
'-

 

 

 

Tepary
(Sept-Oct)

 

+ Germinated
I - Ungerminated
—&-- Weeds

 

 

 

 

 

  
  

 

 

 

..I 4
I" '-I- -. *- "'"— H
40 -H_1—'I—.-: 4"
.. H
, 0 -—=-’—-——I-o—I--o-0—o—o—o—0—1—_j4_-'=
E 45 ' '
(n """""""" 4"...0LI....44_ ------ .14
o T— ...-E
0 50 100 150 200 250 300 350
Thermal Time (°Cd)

Figure 8. Mean density (N) and standard deviation (s) of weeds and germinated and
ungerminated tapm seeds in the field: a) March-April and b) September-October

400

88

 

 

 

 

 

 

250 1..
', Velvet Bean a
200 - I
6'. (Mar-Apr)
E 150 - i.‘
. "*IL.
'2100- "Cl—r"
50 _ ”.00 + Germinated
/ --I-- Ungerminated
.. 0 Leo-or.

 

 

 

 

 

 

 

0'] 30 l I I I I I T I I I
10 5 k .0—44 ,
3*. 0 ' ”0" H
‘0 250 -
Velvet Bean b
200 - (Sept-Oct)
+ Germinated
fill 150 .. --I-- Ungemllnated
_... Weeds
x‘
.H'T“

   
   

11...... -I-l-I-l... . . . .-
-'='-'- Mum—WH—a
I I I I I I I I
I I I I I I I I I
0 50 100 150 200 250 300 350 400 450 500 550

Thermal Time (°Cd)

Figure 9. Mean density (N) and standard deviation ls) of weeds and germinated and

ungerminated W seeds in the field: a) March-April and b)
September-October

 

 
 

 

 

 

Figure 10. Photographs of: (top) white velvet bean seeds that have turned black and
subsided into the soil, and (bottom) sunnhemp seedlings with insect damage

90

 

 

 

20
Velvet Bean
Field Data
15 -
... 0-0——0+0—0-0-—-0
é /
o; i
.2 /
'0' 10 - ”—0
E / ,II--.
8 f I: a";
/ .. -' '
5 - / '. I I ll
/ I I ..
/ —-—- Cumulative % '-_
/ ----- Daily, visible % ~_.
0 ¥ I I I I I T I I “.I—

 

0 50 100 150 200 250 300 350 400 450 500

Thermal Time (°Cd)

Figure 1 1 . Actual vs. cumulative germination percent of tropical velvet bean in the
field

91

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100$
Wheat 3
3° " (Mar-Apr)
60 - + Germinated
°\° I - Ungerminated
40-
,4’400—+———0—0
2° - in. ..I
"-17.
NA 04——.“( . I“.
'E 15 II I I I I I I
*1: 151 ."-:__")--G-—".".—+—_F.
I; 0 ' —o—-O’ 'I- I
100 -
Wheat b
30 " (Sept-Oct)
6O -
0°
40 ‘ + Germinated
20 -
// /’.__.’.\.——+‘.—'.—H_—
A O //
”E 15 f I I I I I
10
4* 5150 .I—H——
.. 0 ——————-—-—.—0~0—0-—-+-e
m l I l I l
100 150 200 250 300 350 400

Thermal Time (°Cd)

Figure 12. Mean percent (96) and standard deviation (s) of germinated and
ungerminated wheat seeds in the field: a) March-April and bl September-October

92

 

100 I a

 

. Lablab
80 - '- (Mar-Apr)
0 60 - + Germinated
°\ 40 _ ' I - Ungerminated

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b
. Lablab
80 - (Sept-Oct)
0 60 _ + Germinated
°\ '. --I-- Ungerminated
40 - I
I Ill-ll
20- ”(N \l "' """ "'1.-
/ ' l °°°° ‘-
(LL/i .‘—*H~o+0.\.
‘1. 15 I I I j I I 1
E10
.. 5 .....
m 0 --JWImwwmu.
I I_fi I I I
50 100 150 200 250 300 350 400 450 500

Thermal Time (°Cd)

Figure 13. Mean percent (%) and standard deviation (3) of germinated and
ungerminated Iablab seeds in the field: a) March-April and b) September-October

93

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12 " a
Sorghum
1O - (Mar-Apr)
8 ...
0° 6 -
4 —I— Geminated
2 _
o—o ,0-—0—o—o——-0-0
0 «re—00V V
NA 4 I I I I I I I
I
E 2
it. 4*... 0.....-—0——-0—o
(D
12 ' Sorghum - b
10 - (Sept-Oct)
,o-o—o—o—o-o-o.\
8 - /—0 \0—0\
e\° 6 - \.
4 "‘ // \
2 " / + Germinated i
- 0 1/
. 4 I I I I I I j
:2 ///'\0—0—0+0-H—o—0-—--0-*"’.+
v 0
(0 I I T I I I I I
O 50 100 150 200 250 300 350 400
Thermal Time (°Cd) '

Figure 14. Mean percent (96) and standard deviation (3) of germinated and

ungerminated bird-raaiatant aarghum seeds in the field: a) March-April and b)
September-October

94

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

100 a
{ Sunnhemp
30 _- l (Mar-Apr)
60 _ - —-0— Germinated
°\° --I-- Ungerminated
4o - '
. f‘nfl“.
20 _ IJ 0
A r ....i...
‘1‘ 1?) I I I I I I I l
E 10
v g -I"-.¢fi"‘-‘4I—-I——.J
(0
100 b
_ Sunnhemp
80 - (Sept-Oct)
a so - + Germinated
°\ N --I-- Ungerminated
4o - -_
20 - // '11:...
'I- , \
.0 o-«l/ ”Wm“...
I 15 I “.I. I l I I fir—T—r—
E 10 .. ' '-.
v 5 ." .
.. ° ' ’7’7‘ ."."".""‘.’""0.—1—.——-W~* I
0 50 100 150 200 250 300 350 400 450 500
Thermal Time (°Cd)

Figure 1 5. Mean percent (%) and standard deviation (5) of germinated and

gngeLminated aannhamp seeds in the field: a) March-April and b) September-
cto er

95

 

100 I Tepary a
(ManApd

 

80 - —I— Germinated

-- I -- Ungerminated

 

 

60-

 

%

 

 

 

 

 

 

 

 

 

 

”E I I I I I I
I». . _— . __ _______.a.
in .
10° Tepary b
so - (Sept-Oct)
0 -. + Germinated
°\ 60 - ‘1 --I-- Ungerminated
‘1.
40" "I l
20- .l-I.
I.. .......
c..." Of’”’4—'++*FH+F‘4J—l
E15 l I I I I I I
£152 _____ I"-"."I-....-I-I.

 

 

I I I I I I I
O 50 100 150 200 250 300 350 400

Thermal Time (°Cd)

Figure 16: Mean percent (96) and standard deviation (s) of germianted and
ungerminated tam seeds in the field: a) March-April and b) September-October

96

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100 in. a
Velvet Bean
80 - (Mar-Apr)
+ Germinated

\° 60 - I" ""‘ Ungerminated

e u ...-.1 i ..... I
40- ... ..... . ........ .
e———e—___.,I
kfr
/
l l I
-I'°. ---- "' """ ' """""" I I
KB“-¢-—¢————e—e
. Velvet Bean b
80 - (Sept-Oct)
I." + Germinated
..I...I ""' Ungerminated
o 60 - .I‘
e .I.
‘I.
40 - I ...... '11....
20 -
‘0—__

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IE1O .. ...... . I..”. ..
fi 5 ".... _. . .- ..

m l l 1 l l l . .7

0 50 100 150 200 250 300 350 400

Thermal Time (°Cd)

Figure 1 7. Mean percent (96) and standard deviation is) of germinated and
ungerminated WM seeds in the field: a) March-April and bl
September-October

CHAPTER 3

SOClO-ECONOMIC FACTORS RELATED TO USE OF VEGETATIVE

COVER AT A TROPICAL FIELD SITE

INTRODUCTION

Socio-economic factors influencing adoption of technology in small-scale
agriculture of the tropics have been ignored in the past in the search for solutions to
land degradation (Conway, 1986). The result has been that often technology with
great potential has not been adopted by subsistence farmers, because agricultural
professionals have made inaccurate assumptions about what farmers want or need,
or they have concentrated on the wrong problems (Chambers at al., 1989).
Therefore, research summarized in this chapter moves one step beyond the
traditional scientific approach to agronomic problems. The research presented here
makes use of survey research techniques (Alreck and Settle, 1985; Casley and
Lury, 1987) to gather information both about what is happening in the aggregate in
farmers' fields at the Dominican Republic field site and about what is hapening
outside their fields that may affect what happens within their fields.

The hypothesis of this study is that quantitative and qualitative analyses of
agronomic practices and socio-economic factors at the tropical field site will provide

an understanding of both that will aid in making cover crop technology site-

97

98
appropriate. Thus, the objective of the research was to identify local agronomic
practices and problems and identify socio-economic factors with potential impact on

adoption or use of vegetative cover.

MATERIALS AND METHODS

A sample of farming households was interviewed in April, 1992, with two sets
of survey questions (Appendix I), one for the head of the household dealing with
farming and one for the spouse dealing with gardening, family health and nutrition.
The study population for the survey included all those families living in housing units
within the village of Buen Hombre, whose head of household was a member of the
local farmer’s association. Each farming household had an equal probability of
being selected for participation in the survey. The overall sampling rate for a
farming household family unit was .67 or 1 in 1.50.

The list of farming association members prepared by the secretary of the
association included 30 names. Twenty households were randomly selected for
interviewing. Final response rate for the study was r= 20/20 = 1.00.

Questionnaires were edited, open-ended questions were grouped into like
categories and responses were recorded on coding sheets. Data were entered into
a computer analysis package in a rectangular format, sorted, checked for “illegal,”
or incorrect, codes and inconsistencies. Since there was a uniform sampling
fraction, taking 1/1.5 of farming households in the village, a weight of 1.5 could be

used to estimate the entire population of farming families.

99
RESULTS AND DISCUSSION
Introduction
Although survey questionnaires are used successfully in many developed
countries to elicit a wide range of socio-economic and political data, this technique
posed some problems for people in Buen Hombre. People in this village do not
normally view the world or interact with it in terms of quantifiable data and
information. Questions about how often and how many were difficult for villagers,
especially with retrospective questions that referred to an entire year. In spite of
this, villagers appeared to enjoy the extra attention and gave meaningful answers to
many questions. Data from formal interviews were supplemented with key
informant interviews on specific topics, informal walks through the village with
small groups of villagers to survey agriculture, trees or plants and group meetings

with relevant adults to construct a seasonal calendar and draw a village map.

Demographic information

The survey questionnaire provides a useful perspective on villagers and village
life. Farming families range in size from small to large, with approximately four
children and two adults per family (Table 1). Only 45% of household heads were
able to respond to a question about annual income. Mean agricultural income for
the 35% of respondents with incomes below $715 U.S. was 8284. Ten percent of
respondents had annual farm incomes above $2,860, with a mean of $4,100.

To a question about ma] family income over the past year, a year of drought,
45% responded, ”Don’t know;" 25% said none or very little and the mean for those

responding with an amount was $381 . Key informant interviews elicited the

100
information that during the month of December and sometimes January, when
crops had just been planted and the sea was too turbulent for spear-fishing, many
villagers simply slept. They were not taking in enough calories to do anything else

(T. Perez, personal communication).

Agriculture and farming

Fifty percent of household heads never attended school, 30% attended for two
or three years and none completed more than 6 years of schooling. Nineteen
percent of the remaining adults sampled had no schooling, 27% attended one or
two years of school and 14% finished seventh or eighth grade.

Fifty percent of farmers farm one plot, 35% farm two and 15% farm three.
Thirty-three percent inherited their land, 43% obtained it from the state by
cultivating the land over a number of years, 5% bought their land and 10% received
it through some combination of the above. Ten percent rented the land they work.
The mean size of land owned was 69.4 tareas, or 4.37 hectares. Sixty percent
farm flat land, 10% farm slopes and 30% farm both. Slopes are 6-12% (farmed by
10% of respondents), 12-18% (5% of farmers), 18-25% (10% of farmers) and 5%
of farmers work slopes greater than 25%. Fifty-five percent farm more than one
soil type. Eighty-five percent farm black soil, 40% farm yellow, 10% farm red,
15% work sandy soils and 15% stony. Only 15% use soil amendments (manure,
ashes and undecomposed organic matter), but 85% use insecticides, provided by
the tobacco company, for tobacco. Ninety-five percent save seeds from one year
to the next, and 35% exchange seeds or cuttings with other farmers.

All farmers surveyed grow tobacco for cash, as well as beans; 95% grow corn,

101
70% pigeon peas, 65% a tropical sweet potato variety and 60% grow cassava.
Farmers also mentioned eggplant, tomatoes, broad beans, onions, watermelon,
carrots, and cucumber.

Seventy-five percent of farmers sow the same crops each year, and 80% sow
more than one crop per field. By their own account, only 10% of farmers do any
experimentation and that is to test which crops do better on different soils. Ninety-
five percent save seeds from one year to the next. and 35% exchange seeds or
cuttings with other farmers. I

Because rainy season onset varies annually, the timing of field clearing with
machetes, hoes, a government tractor or the tobacco company tractor also varies
and is often completed over a period of several months. Fifty-five percent of
respondents clear fields in November, 35% also work in October and 25% in
December. Tilling and planting generally occur between October and December,
with some harvesting as early as February. Sixty percent of farmers harvesting
some crops in March and 40% in April. Seasonal labor requirements, in a calendar
based on information gathered during group meetings with 90% of adult villagers,
shows average monthly precipitation and gives a rough indication of time use in the
village by gender (Figure 1). Months of greatest rainfall are accompanied by high
farming activity. Low rainfall tends to be paired with increased fishing activity, as
heavy rainfall causes coastal turbulence and impedes fishing.

Ninety-five percent of families give some of their harvest to others. Eighty
percent were unable to attach a monetary value to those gifts, but 8104 was the
mean value given by those who responded. Eighty percent own farm animals,

chickens, goats, pigs or cows; seventy percent give farm animals or farm animal

102
products to others and 25% sell to others. Sixty percent gather wild plants for use

as medicine, Spices or in the home.

Gardening

A separate set of questions was asked of the spouse of the head of household.
Fifty-three percent of the 19 sampled wives responded that they had had a garden
the previous year. Ninety-five percent said they plant a garden when it rains.
Seventy-five percent of these gardens are flower gardens, and 20% are a mix of
flowers and vegetables. Thirty-seven percent of the women amend their soils with
manure, ashes and fertilizer; and 37% add insecticides. Twenty-six percent buy

seeds. 68% save seeds from year to year and 95% exchange seeds or cuttings.

Health and nutrition

When there is sufficient food, 79% prepare three meals a day. When food is
insufficient, 53% prepare two meals and 42% prepare only one. Village women
cook white rice, beans and sometimes fish, when there is little food. Vegetables.
bread and milk are added to meals in good times. Forty-two percent of women
supplement their family's diet with wild plants, such as leafy greens and chicory.

Women report their children are ill anywhere from several times a month (37%)
to several times a year (37%) with flu, diarrhea, fever and anemia. AdUlts are ill
less often, generally two to four times a year with flu, headaches and various
infections. The responses from both men and women verified by observations
during field work, portray a harsh subsistence existence with malnutrition, ill-health

and infectious diseases for many villagers much of the year. Because their parents

103
can no longer support them, children are often sent out of the village to work by

age 12.

Quality of life

One way of ascertaining quality of life indirectly is to ask respondents how
they would improve their lives. Responses to this type of question vary somewhat
by gender, as Table 2 shows. For improving family life, men mention employment
most frequently and women mention education. Both men and women agree that

water and roads are the most important factors in improving conditions for the

 

village as a whole. Agriculture projects are mentioned by only 10%, either because
of a failed tobacco project in 1984, with a resulting lack of hope by villagers for
agriculture. or because agricutlural projects will need to be tied to other projects (R.

Stoffle, personal communication).

Vegetative cover

In the survey, no direct questions were asked of villagers about the use of
vegetative cover crops in the dry season. Because of interpersonal ties that had
developed between villagers and the interviewer, there was a strong possibility that
answers would be biased toward what villagers perceived the interviewer would
want to hear. Instead, key informants (two different presidents of the farmer's
association) were asked if they thought villagers would be interested in or willing to
grow drought-tolerant crops during the dry season, providing the crops produced
food or animal feed. Both men responded with a definite yes (R. Cabrera and A.

Burgos, personal communication).

1 04

In another indirect approach to assess village attitudes to specific cover crops.
seedlings were left to survive on their own when field experiments were completed.
Jack bean, from an early hillslope experiment (data not reported). grew to maturity
and produced seed with no rain beyond that which fell in the first week after
planting. Farmers called the plant ”the miracle bean." Tepary been also grew to
maturity with whatever rain fell during the dry season at the end of the March-April
experiment. Beans were subsequently harvested and cooked by the landowner's
wife in a dish that the entire family was said to have enjoyed (T. Perez, personal
communication). This farmer requested that every villager be given access to
tepary seeds for dry season planting.

The situation in the village late in the dry season and early in the rainy season
is so severe, that even though villagers generally do not experiment with ways to
improve agriculture, there is great potential for crops like tepary and jack bean. If
such crops are introduced carefully, and villagers are shown when to plant, the
necessity of overseeding and protecting plots from goats. etc., the species tested in

this study could make a positive difference in villagers lives' and ecosystems.

CONCLUSIONS
Survey responses indicate there would be great demand for off-season, food-
or income-producing species in Buen Hombre. Also, vegetative cover would be
likely to prevent at least some erosion. as 30% of farmers cultivate land with a 6%
or greater slope.
Most farmers in the village fish, as families who depend entirely on farming

migrated out of the village by late 1993. due to an extended drought and

105
persistently low tobacco prices (A. Burgos, personal communication). Yet wives'
responses indicate that combined fishing and farming activities do not provide
enough food for three meals a day throughout the entire year, even when taking
into account villagers’ proclivity to share what they have with others. In addition,
responses of household heads indicate minimal cash income each year. The two
leading responses of sampled adults on how to improve fmily life are employment
and education. Presumably education is perceived as a path to employment.

These socio-economic, diet and health variables indicate the need for additional
food and income in the village. The findings of this study suggest that villagers
would be eager to plant off-season crops and would willingly incorporate at least
one of the tested species into their diet. A seasonal labor calendar (Figure 1)
indicates that March and April are already very demanding in terms of male labor,
with heavy commitments to harvesting and spear fishing. May appears to be the
best month for planting of vegetative cover, both in terms of labor commitments
and precipitation. Additionally, there are lower labor commitments for males in the
months right after May, when weeding and harvesting would occur.

Thus, a traditional survey, has provided initial information about local
agronomic practices and problems and socio-economic factors. These data indicate
that certain species of off-season vegetative cover would be likely to be adopted
and used by villagers. especially with more extensive field testing in collaboration
with villagers and professionals. The process of change needs to include research

and development, in which change is evaluated as it occurs.

LIST OF REFERENCES

Alreck, Pamela L. and Robert B. Settle. 1985. The Survey Research Handbook.
Richard D. Irwin, lnc., Homewood, Illinois, 429 pp.

Casley, D.J. and DA. Lury. 1987. Data Collection in Developing Countries, Second
Edition. Clarendon Press. Oxford, England, 225 pp.

Chambers, Robert, Arnold Pacey and Lori Ann Thrupp. 1989. Farmer First: Farmer
Innovation and Agricultural Research. The Bootstrap Press, New York, New
York, 218 pp.

Conway. Gordon R. 1986. Agroecosystem Analysis for Research and Development.
Winrock International, Bangkok, Thailand, 1 10 pp.

106

107

Table 1. Household composition of farming families, Buen Hombre

 

r h I Mean Range
..#.. ..#..
Total 5.9 1-13
Males 3.1 1-7
Females 2.8 09
Age 21 or over 2.0 1-3
Under age 21 3.9 0-11

 

108

Table 2. Factors that would improve life for families and village as a whole. opinions
of farmers and wives, first five mentions

 

 

 

Factors that would Factors that would
improve life for improve life for
respondents family1 village’

Factor Males Females Males Females

 

 

 

% mentioning factor

Employment 60 1 6 1 1
Education 35 53 10 1 1
Water 1 6 85 79
Food and health 20 11

Roads 1 1 75 79
Electricity 1 0 45 68
Agriculture project 10

 

1 Question respondents were asked: If anything were possible, what would you
like to see for the future of your family?

2 Question respondents were asked: If anything were possible, what would you
like to see for the future of Buen Hombre?

109

Buen Hombre, Seasonal Labor Calendar

 

ASONDJFMAMJ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

80 ‘”
Joint 60 -- Harvest
“hot: 40 ‘" Land Planting,
(II Wk") .... preparation Land preparation, weeding. /

20 planting harvesting I

 

 

 

 

 

 

 

 

 

 

ASONDJFMAMJ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

so __
Women 60 Tending children
(1).”),ch 40 Laundry, sewing
( W ) 20 Cleaning, gathering water. gardening
Cooking
A S O N D J F M A M J
Men :3 ::
Only
(hwlc') 4o -— ___J_L
20 -- Spearfishing W Spear fishing
A S O N D J F M A M J
Mean 100‘-
Monthly -..
Rainfall 80
(1934- 60'-
1990) __
(mm) 40
20--

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 Months of the year starting with August
2 75-85% contribution from men; 15-25% contribution from women

Figure 1 . Seasonal labor and precipitation calendar. Buen Hombre

CHAPTER 4

ECOLOGICAL AND REMOTE SENSING ANALYSES OF A CARIBBEAN VILLAGE:

A CASE STUDY FROM THE DOMINICAN REPUBLIC

OVERVIEW OF INTERNATIONAL DEVELOPMENT

AND ARGUMENT FOR A NEW APPROACH

For many years. the approach to international development has involved the
imposition of solutions and technologies of the northern hemisphere on countries of
the South (Korten, 1990: Reintjes et al, 1992). Traditional development efforts
have generally involved importing technologies to deal with specific, individual
development problems, ignoring environmental and socio-economic heterogeneity of
indigenous systems (Conway, 1986). Attempts to simplify complex, local
subsistence management systems by introducing costly, non-renewable, external
inputs have failed to improve subsistence life in the tropics (National Research
Council, 1993).

As an example, technological change introduced to agriculture has usually
involved mechanization, improved seeds and the use of pesticides and fertilizers,

and has emphasized large-scale production by large landowners. Specifically, in

110

111
Latin America, it has resulted in countries becoming net importers of agricultural
chemicals and machinery, with increases in production of export/commercial crops
(Altieri, 1992). For many subsistence farmers who have converted to cash crops,
the conversion has been accompanied by ”loss of food self-sufficiency, genetic
erosion, loss of traditional farming knowledge. [and] permanence of rural poverty"
(Altieri, 1992).

High-input development approaches have fostered dependency and instability,
while increasing risks, rather than reducing them (Lightfoot and Noble, 1993).
Again in Latin America, there has been a trend toward diminished government
involvement in technological change and increasing private sector involvement. The
private sector's focus has been on technology that increases profits (fertilizers.
pesticides, biotechnology). rather than on technology that promotes sustainability
and stability (mixed cropping systems, biological insect control, green manure)
(Altieri, 1992).

Increasingly today. however, traditional development perspectives are being
replaced by more sustainable approaches that are participatory and multi-disciplinary
and based on indigenous tropical cultures and environments. The reasons for this
shift are well-documented (Chambers at al, 1989; Conway, 1986; Eswaran et al,
1993; Lal and Ragland, 1993; Senanayake, 1984).

Senanayake (1984) gives an example of substituting tractors for buffaloes in
Sri Lanka in order to save time and labor. Direct losses to villagers, due to the
replacement of buffaloes, included loss of milk and manure. Indirect losses
stemmed from the disappearance of buffalo wallows, which provided, among other

things, refuge for fish in the dry season, when rice paddies were dry. The fish were

1 12
a protein source for landless villagers and were predators of the larvae of malaria-
carrying mosquitoes.

In order to shift successfully from traditional development approaches to more
sustainable approaches, scientists, development professionals and government
officials need a basic understanding and knowledge of local human systems and
ecosystems. The key to understanding complex, local systems and to developing
management systems that increase ecosystem production, while conserving and
sustainably exploiting them, is indigenous participation and knowledge. By
involving local communities in assessing their natural resource environments and in
deveIOping more productive systems, fragile socio-economic and environmental
conditions can be strengthened and enhanced (Lightfoot and Noble. 1993). Change
based on indigenous systems can ensure cultural and ecological compatibility.

Critical to the development and introduction of new technology that is also
sustainable is an emphasis on innovations that are ecologically appropriate, such as
dryland agronomic management techniques and xerophytic cultivars for arid regions
(Lightfoot and Noble, 1993). rather than high-cost irrigation, chemical and
machinery inputs. The advantage of particpatory approaches is that they can
contribute to sustainable development by adapting external technologies to local
conditions through collaboration with local people, or through simple refinement and
improvement of already existing local technologies. The disadvantage of the use of
participatory methods alone (to the exclusion of technological methods) is that the
result may be too simplistic for the situation.

Throughout the world, natural resource problems are frequently intensified by

population pressure on the environment. increasing the rate and severity of

113
degradation. Problems are further complicated by diverse human groups with
widely divergent Opinions about what the problems are, what the causes are and
how to solve them. For difficult, multiple-issue problems, technological solutions
alone can also be insufficient to deal with complex, dynamic interactions between
people and their environments.

Wilson and Morren (1990) describe a comprehensive, practical procedure for
dealing with complex agriculture and natural resource problems. It combines
participatory methods used in international development in countries of the South
(Chambers at al., 1989; Haverkort et al., 1991) with soft systems methods used in
industry and government in countries of the North (Checkland and Scholes. 1990).
Wilson and Morren present a strong case in favor of what might be called a
”participatory-systems" approach to "messy," multi-faceted population-environment
problems. Briefly and very simply, this approach requires participation of all
relevant parties to a specific situation. Through examining the situation from
different perspectives and by using a systems approach, the goal is to reach
agreement on what the problem is, what would constitute improvement and what
methods and technologies would achieve agreed-upon goals. This technique is
participatory, holistic and multidisciplinary. The method combines basic and applied
science with 'hard" and 'soft" systems science, using participatory methods.

The first step in the participatory-systems process involves conducting
quantitative and qualitative inventories of relevant ecosystems and related human
systems (Wilson and Morren, 1990). These inventories form the basis of
subsequent steps in the process. They are used to define specific human-

environment problems in a region, design appropriate research; propose and put into

114
practice feasible. sustainable and equitable solutions; monitor change and evaluate
alternative solutions prior to field testing. If done properly. initial inventories and
resulting analyses can explain a few critical relationships in both ecosystems and
human activity systems, focusing limited research and development resources on a
few key areas where significant improvements can be made. The careful use of
existing resources is particularly important in developing countries where

institutional and professional human resources are often inadequate.

BUEN HOMBRE: A TROPICAL CASE STUDY

In 1985. Stoffle (1986) conducted research in an isolated farming-fishing
village on the northwest coast of the Dominican Republic. There were two key
findings in that initial and subsequent research:

0 first, a development project that was highly successful from a technological

standpoint and was appropriate from a socio-cultural perspective, but failed

because of competition between the development agencies involved (Stoffle et

aL,1991)

O and second, villagers modified and improved introduced technology based on

expertise with and knowledge of local species and ecosystems.
Subsequent to that research and the project failure, village leaders stated that they
would not agree to any further development projects in the village unless they were
actively involved, had veto power and strong leadership roles (N. Gomez and T.
Perez, personal communication).

Another study (Stoffle and Halmo. 1991). that overlapped with the initial

stages of research conducted by this author and involved collaborative research

1 1 5
efforts, found that along the northwest Dominican coast. local ecosystem change
and the human dimensions of that change could be monitored and predicted through
interdisciplinary applications of remote sensing research. Further, such research
could be used in planning and protection of coastal ecosystems.

These two studies indicated that the village of Buen Hombre (Figure 1) and the
situation occurring there would provide an excellent example of the dynamic and
complex natural resource crises for which a participatory-systems approach to
problem-solving is appropriate. A potential crisis is developing in Buen Hombre,
involving people and their natural resources. Decisions being madeover the next
few years may have irreversible consequences for the future of this region. The
situation is complex and constantly changing. It involves subsistence villagers who
depend on fragile marine and terrestrial ecosystems for survival, outsiders who are
encroaching on the resources in these ecosystems illegally and destructively, a
potentially harmful government edict declaring the region a tourist zone (J. Serulle,
personal communication). and apathetic, corrupt local government officials.

This paper presents a case study of Buen Hombre within the framework of the
participatory-systems model described by Wilson and Morren (1990). More
specifically, it presents summaries of collaborative research and of previous
research in the village (Stoffle and Halmo, 1991) and analyses of preliminary
inventory data collected as a first step in the participatory-systems process. To that
end, using quantitative and qualitative tools from several academic disciplines. data
were collected between 1990 and 1993 during six research trips to this coastal
village to assess critical human and ecosystem resources.

Central issues of the situation in Buen Hombre will be presented from a multi-

116
disciplinary perspective. The expectation is that this background information will be
used by relevant groups of people to test and evaluate the participatory-systems
approach in developing a comprehensive ecosystem management system for the
region. Buen Hombre would serve as an excellent pilot project for the Caribbean,
because it is representative of a situation common to the islands, in which human
groups are engaged in intricate. survival-based interactions with closely linked,

stressed ecosystems that serve as a buffer between land and sea.

MARINE AND TERRESTRIAL ECOSYSTEMS
Coastal marine and terrestrial ecosystems along the northwest coast of the
Dominican Republic are intricately related ecologically and to human subsistence

activity. Both ecosystems and related human activity systems are discussed.

I. Reef and Coastal Mangrove Ecosystems: General Background

Mangroves are tropical, forested, coastal wetlands that ”thrive in the shelter of
coral reefs” and provide a spawning ground for fish, as well as a home for crabs,
shrimp and mussels among the mangrove roots (Weber, 1993). Mangroves serve
to stabilize coastlines from weather damage, protect coral reefs from silt due to
erosion and are in turn buffered from the ocean by coral reefs. In coastal areas
where mangroves have been cut, fish populations have dropped, due to the key role
mangroves play in the life cycle of fish (Weber, 1993).

Coral reefs support algae and grasses, which in turn support diverse
populations of marine animal life. Reefs are considered second only to tropical

rainforests in biological diversity, with considerable potential to contribute to

1 17
science and medicine (Weber, 1993b). However, coral reefs are easily stressed (or
'bleached") and can be killed by overfishing, abnormal temperatures, excessive
fresh water, excessive human activity or high rates of sedimentation due to erosion.
Because humans "disrupt and destroy reefs too often for the corals to recuperate
fully" (Weber, 1993b). human disturbances are more difficult for reefs to recover
from than natural disasters.

When reefs are stressed, coral polyps expel zooxanthellae, the red, yellow or
orange algae which live symbiotically in the translucent coral tissue. providing food
and oxygen from photosynthesis to the coral and receiving structural protection
from the coral in return (Weber, 1993b). When zooxanthellae are expelled, reefs
appear white. as the white calcium carbonate coral skeletons become exposed.
Because of this change in color, the process of reef degradation, or ”reef
bleaching,” can be monitored, using satellite images (Figure 2).

The worldwide trend for reef systems, documented by reef scientists over the
last two decades, is that generally only remote reefs with little human activity have
remained healthy (Weber, 1993b). The Dominican Republic is one of 18 countries,
including neighboring Haiti, Cuba, and Jamaica, with seriously devastated reef
systems, due to dense coastal populations and heavy coastal development (Weber.
1993b). Sediments resulting from deforestation, especially from mangrove clearing,
wash into the sea and block the sunlight needed by zooxanthellae to complete
photosynthesis. The sedimentation begins a chain reaction that leaves coral
weakened and more vulnerable to disease and other stresses.

Coastal development, often for tourism, drives mangrove destruction. The

destruction results not only in increased siltation in coastal waters, but the

1 18
destruction of shellfish habitats and fish spawning grounds. Sewage and urban
runoff are introduced, which degrades coastal water quality, fostering
eutrophication (influx of nutrients from soils and sewage), which in turn
overfertilizes zooxanthellae, which multiply to toxic amounts inside coral polyps

(Weber, 1993b).

ll. Reef and Coastal Mangrove Ecosystems of Buen Hombre

The village of Buen Hombre, "Good Man,” lies 44 km northeast of the Haitian
border (between 19°51 '0" and 19°52’10” N latitude, 71 °23’10" and 71 °25’30'
W longitude). offshore from a triple reef system in the middle of one of the longest
stretches of coastal mangrove growth in the Caribbean (Figure 3). The isolated
Buen Hombre reef system is one of the most vital, biologically diverse and
ecologically complex systems remaining in the Caribbean (Luczkovich, 1991). It
has been fished sustainably for a hundred years by Dominicans descended from
Cuban immigrants, and four hundred years before that by pre-Colombian Indians.
The northwest coast's triple reef system has (an inner, middle and outer reef, with a
break in the long reef system just offshore from Buen Hombre, permitting boat
passage to and from the village.

Through ground-truthing and interpretation of time series Landsat satellite data
(1975, 1985, 1989) for the northwest coast, Wagner et al. (1991) and ERIM
(1994) reported "early indications of environmental stress due to human factors
[fishing and tourism)" in neighboring reef systems east of Buen Hombre. These
reefs, approximately 40 km to the east of Buen Hombre, at Punta Rusia, have

substantial tourist activity and very few mangroves. Reefs to the west,

1 19
approximately 40-45 km away, near the larger Dominican city of Monte Cristi, are
”fished out.” Reefs just across the Haitian border to the west are dead.
The obvious question is: what is different about Buen Hombre? Why are its

reefs healthier than those of its neighbors? There seem to be three related reasons:

A. Population

1 . Low population:

The 1981 census reports 397 people in 82 occupied dwellings in Buen Hombre
(Castillo, 1991). Eleven years later, in the middle of a 4-year drought, an unofficial
census completed under the direction of the author showed population had fallen to
329 occupants (188 males, 141 females) in 83 dwellings. Population in the village
traditionally fluctuates with rain, or anything that affects subsistence activity. In
periods of contracted drought. there is permanent and temporary migration to cities
and towns inland. Migration is the traditional method of relieving population
pressure on limited natural resources. Women tend to emigrate in greater numbers.
perhaps due to the ease with which they can find domestic employment.

2. Low population density:

The census mapping area that includes Buen Hombre is the Buen Hombre
District and includes three other villages with a total 1981 population of 929 (Table
8) over a total of 4,091 hectares, resulting in a population density of 32.4 people
per km’, or approximately one person for every 3 hectares (7.4 acres). This figure
is relatively low, compared to 277.6 peOple per km’ in El Salvador, the most
densely populated Central American country, or 65.1 people per km2 in Costa Rice,

with the second lowest population density in Central America.

1 20
8. Physical environment:

Buen Hombre is isolated and separated from the rest of the island to the south
by the Cordillera Septentrional mountains (Figure 1). The topography is
mountainous and hilly, with a gradual descent to the sea. The rugged, dirt road
north from the main highway (Highway 1, Carretera Duarte) is a one-hour drive to
Buen Hombre. The climate is semi-arid, as the village lies in the rain shadow of the
mountains. Annual rainfall is 600 to 700 mm, with an unpredictable rainy season
between October and January to March, with the driest months falling between
July and September (Portman et al, 1991). Droughts are common.

“Potable" water must be brought in by burro or motor during most of the year. '
A few houses have aljibes, simple roof water catchment systems with cement block
cisterns. The lagoon also catches and stores rainwater. for a few months after the
rainy season. The Buen Hombre well, with agua salada, saline water. is used for
watering stock and kitchen gardens, and for laundry and bathing. The closest
drinking water source, when filled by government water trucks, is the government
cistern (3 km away). Most villagers pay local moped owners to transport water
from at least 4km away in Las Canas.

Water samples from three of the four fresh ("sweet") water sources used by
villagers were sampled by the author according to standard Michigan Department of
Health (MDPH) procedures in 500ml containers provided for that purpose and were
later analyzed by the MDPH Water Supply Division. Test results validate villagers'
perceptions of local well water as being muy mal, very bad (Table 1). It is highly
mineralized. with unacceptable levels of nitrates and sulfates. Lead levels are

somewhat high, but could be naturally occurring (Williams, personal

1 21
communication). Water from district lagoons falls within acceptable limits for tested
characteristics. though bacteriological tests for coliform bacteria were impossible to
perform within the required time frame from source to testing laboratory. Intestinal
problems are common among villagers. Farm animals use the lagoons freely as their

water source and siesta spot.

C. Conservation ethic:

Village fishermen know their survival depends on reef health and conservation
of marine flora and fauna. Villagers display a strong conservation ethic, which
results from a long-term relationship between villagers and their ecosystems.
involves a sense of ownership toward local ecosystems and involves sophisticated
knowledge of the ecosystem (Stoffle et al., 1994). lnformally, fishermen avoid
fishing species with low populations for a year or two and ban the use of diving
equipment. because of the advantage it provides humans over fish.

To illustrate anecdotally, a fisherman from the neighboring village of Las Canas
was told he could not fish in Buen Hombre with his diving tank. He was then told,
”If you are willing to fish with fins and a spear, as we do. you can swim beside us,
and we'll welcome you as a brother" (T. Perez, personal communication).

In summary, isolation, low rainfall and lack of potable water all control
population and tourism, which are also responsible for keeping human activity on
the coral reefs low. Currently, low rainfall is the main factor preventing erosion and
reef degradation due to siltation, and local norms prevent unsustainable fishing
practices. City fishermen from Monte Cristi to the west do not have the direct

survival link to the health of their reefs, as village fishermen do. Based on the

1 22
behavior of these city fishermen in Buen Hombre, cultural norms in favor of

sustainable practices are weak or absent among outsiders.

lll. Terrestrial Ecosystems of Buen Hombre

Inland from the reef and coastal mangrove ecosystems is the valley of Buen
Hombre (Figure 3). flanked to the south, east and west by mountains and hills. The
main north-south road cuts through the horseshoe valley on the east edge, with
houses. shops and bars clustered along the road. There is farmland up hillsides to
the east of the road. and in the valley west of the houses. Before the road drops to
the sea at the north edge of town, branches of the road split east and west, running
parallel to the coast, with more houses and farmland adjacent to the road.

As in much of the rainfed tropics, the small-scale. low resource agriculture of
Buen Hombre occurs in a complex, diverse environment and depends on the whim
of weather, or more precisely, whether or not, when and how much it rains.
Temperatures are tropical, moderated by near constant ocean breezes, and are not
limiting for agriculture. Weather data obtained from historical accounts (Halmo et
al, 1991), historical records (Portman et al, 1991) and field research (Chapter 2)
indicate that lowest annual temperatures are approximately 19°C. Highest
temperatures reach 33°C in July and August, with mean daily temperatures of 25 to
28°C. Relative humidity generally ranges from 60 to 70%. As villagers report, the
most limiting agronomic factor in this region is low rainfall.

The goal of village agriculture, past and present, has been to reduce risk and
maintain subsistence production. Of necessity and like most subsistence farmers

worldwide, the approach of village farmers to management of their agroecosystems

123
has been multidisciplinary and holistic.

Agriculture (data collected through ethnographic interviews with two farming
association presidents) is a combination of a tobacco (Nicotiana tabacum) cash crop
grown in monoculture. with a mixed cropping system of subsistence root
vegetables, including cassava/yuca (Manihot esculenta), sweet potatoes/batatas
(Ipomea batatas), yams/flame (Dioscorea spp.), potatoes/papas (Solanum
tuberosum) and tannia/yautla (Xanrhosoma mafaffa), as well as dry beans
(Phaseolus vulgaris). broad beans/babe (Vicia faba), corn (Zea mays). pigeon peas
(Cajanus cajan) and an assortment of vegetables and fruits. Crops are rarely
chemically treated or fertilized. though some pesticides are applied to tobacco.
Labor is generally manual, involving all but the youngest family members. Village
livestock include pigs, goats. sheep, cattle, burros. chickens and turkeys. Every

family owns a few chickens.

A. Land Use

Satellite image data analyzed by Wagner et al. (1991) delineate two types of
mangroves, permanently and intermittently submerged. These analyses also show
that the most common terrestrial ecosystem surrounding Buen Hombre farmland is
forest, ranging from light to dense, varying between degraded, cactus and dry
forests. Rangelands and savannahs are the next most common land use category.
with some bare soils west of the village on mountaintops and hilltops.

In a second unpublished remote sensing project by CEUR-CARTEL (Centro de
Estudios Urbanos y Regionales - Centre d’AppIications et de Recherches en

Télédetection). aerial photos taken in 1958, 1966, and 1984 were used to generate

1 24
land use maps, land use intensity and erosion risk maps (St.-Pierre, personal
communication).1 PAMAP-GIS maps of unpublished data were provided by St.-
Pierre in machine-readable disk format and then translated to ERDAS. reformatted
and redrawn in ATLAS-GIS by the author (Figures 5, 6, 7).

Table 2, based on information provided by St.-Pierre, was modified and
translated from Spanish by the author and lists different land use categories used in
Figure 5. Categories in Figure 6 were based on subjective ranking of land use
categories in Figure 5, with forests ranked as low intensity land use and rainfed
agriculture as high intensity (St.-Pierre, personal communication). Categories in
Figure 7 for erosion risk potential were based on relative risk factors of slope,
vegetative cover and land use type (Figure 4).

Detailed land use distribution (Table 3) and total land area for each major land
use type (Table 4) between 1958 and 1984 for the Buen Hombre census district,
which is 7.6 km south, 3.0 km west and 5.0 km east of the bay, were quantified
based on CEUR-CARTEL data. Over the 26-year period beginning in 1958. there
was a decrease in farmland and a corresponding increase in grazing lands, with a
constant 25 to 26 km2 of forested area, or 62% of total district (and. Temporal
differences occurred not so much in total land area per category, but in the spatial
distribution of different land use categories (Figure 5).

The classification system (Table 2) used in Figure 5 highlights the different
types of agriculture practiced in the Dominican Republic. In Buen Hombre, for

example, no land is allocated to irrigated agriculture (Category 2.2 in Table 2).

1The author is collaborating with St.-Pierre on a paper for publication. References to
St.-Pierre’s portion of that collaborative effort are cited here as unpublished data.

125
indicating that district producers are small-scale, agriculture is low input and there is
no water source. Nationwide, increased population between 1958 and 1984
corresponded to decreases of land area in forested land and increases in agriculture
and pastureland (St-Pierre, unpublished data). In Buen Hombre, where district
population increased 87% between 1960 and 1981 (Table 5), the total forested
area remained constant from 1958 to 1984 (Table 3). but there was a 304 hectare
increase in land allocated to moderate intensity land use, with a 270 hectare
decrease in land under high intensity use (Table 6). Figure 6 illustrates the spatial
distribution of these data, showing substantial change over the 26-year period.

The CEUR-CARTEL data for erosion risk potential show 40% and 55%
decreases in land area at moderate and high risk of erosion, respectively, between
1966 and 1984, and a 36% increase in land at very high risk of erosion (Table 7).
Due to the permanency of slope locations, Figure 6 shows less change in the
location of susceptible areas, compared to the figure for land use intensity, but
substantial spatial change back and forth between the four risk categories over
time. Land area at very high risk for erosion decreased from 508.5 hectares in
1958 to 421.0 hectares in 1966, increasing again to 570.5 hectares in 1984.
These data show clearly that erosion risk potential in this region fluctuates with

changing environmental conditions and human activity.

B. Soil Resources
Buen Hombre has three general soil types of agronomic importance to villagers
-- “black,” ”yellow” and "mixed.” Generally, black soils are located in the valley

and yellow soils on slopes. All are moderately fertile, calcareous and productive for

1 26
a wide variety of crops when there is rain. None appear to have physical or

structural limitations for agriculture (Chapter 2).

C. Transocts

Two parallel North-South transects of developed and undeveloped lands were
completed on walks with key informant villagers for comparison of indigenous
ecosystems to local agroecosystems. Each transect was approximately 1,250
meters in length. Land use and vegetation changes were noted as elevation
increased with distance from the sea, and composite soil samples made up of 15
samples from a 10 m’ area from the surface 0 to 0.05 m were taken at the
approximate midpoint of each major elevation/vegetation change. Soil samples
were analyzed for pH, texture and color.

The agricultural, or developed land transect, followed the main N-S road and
was surrounded by village houses and farm plots. The transect of undeveloped land
was to the west of the main road, beginning at the sea, approximately 500 m west
of the north tip of the road, and followed an alternating SW-NW pattern of four
250-meter segments to the base of and then up the village mountain, bordering the
valley farmland on the west. (See Figure 3 for transect path.) The mountaintop
(lat. 19°51’58.4" N, long. 71 °25'4.3" W) had an elevation of 144 m, lay 1,250 m
due west of the village road and 650 m due south of the sea.

As part of the transect data, a collection of indigenous botanical specimens
was started, using standard plant collection procedures (Jones and Luchsinger,
1986), in February, 1991, during the last month of the rainy season. A few

specimens were collected at each of the major elevation changes from beach to

127
foothills. A total of 23 specimens were collected initially, with the intent of
increasing the collection on a subsequent trip. However, an extended drought
prevented collection of additional specimens. Specimens were identified by the
Michigan State University Herbarium and by Dr. Thomas Zanoni. National Botanical
Gardens. Santo Domingo, Dominican Republic.

In addition. ethnobotanical interviews, using methods described by Stoffle et al.
(1990). were conducted in Buen Hombre with key informants, selected for their
knowledge of indigenous species. Data were collected on walks with key
informants, from sea level to an elevation of 140 meters. Plants and trees were
photographed; interviews were recorded. Six sets of on-site ethnobotanical
interviews were conducted on dates representing the end of the rainy season. a few
months after the rainy season, and the dry season. Interview topics included
common name, specimen location, micro-ecological zone, general soil type, growth
habit, striking botanical features, height of specimen, maximum possible height,
seasonal color variations and medicinal and non-medicinal uses. Species were
identified using two Dominican botanical dictionaries (Geilfus, 1989; Liogier, 1974),
and tolerance/adaptation to environmental limitations was noted for each.

Briefly, the results of those interviews indicated that villagers use terrestrial
vegetation (plants, cacti, scrub, bushes and trees) in multiple ways, and utilitarian
knowledge of approximately 95% of local species is comprehensive, sephisticated
and passed on orally between generations. Indigenous plant species are many and
varied (Table 8). with 38 species belonging to 26 families identified in initial
inventories as being important to villagers for stock forage, spices, human or bird

food, fence posts, medicine, lumber. etc. Adaptive strategies exhibited by these

1 28
species are rich and varied (Geilfus, 1989; Liogier, 1974), implying that to compete
effectively, introduced species need to possess tolerance and avoidance/resistance
mechanisms for dealing with the specific ecosystem limitations of this region
(herbivorous insects, low rainfall, high pH soils).

ln tree inventory walks, key informants identified 55 species from 33 botanical
families (Table 9). Most, if not all, of the most common tree species (including
bushy plants and cacti) are also adapted in one or more ways to harsh environments
(Geilfus, 1989; Liogier, 1974). Many are leguminous. Many tolerate drought,
insects or high temperature; infertile, alkaline, calcareous or saline soils; and rocky
soils or sandy soils.

The mix of native vegetation (Tables 8 and 9) in undeveloped lands (Figure 9)
suggests a more ecologically appropriate agricultural management system for
developed lands (Figure 8) of the region - multi-story mixing of diverse, high pH-
tolerant. drought-tolerant/resistant grass, plant and tree species. Concerted
management efforts along these lines have potential to increase agroecosystem

diversity and stability, production and income.

IV. Human Factors

The human factors discussed here are potentially critical factors in the success
or failure of sustainable ecosystem management in the region. Human activity
systems in Buen Hombre are based on productive (farming and fishing) aspects of
the two main ecosystems. Listed below are six cultural elements observed in the
village that appear to be both a response by villagers to their human and natural

environments, and an explanation of or motivation behind villagers' behavior in

129

interactions with both environments:
0 My - Sovereignty is highly valued throughout the Caribbean because
of the colonial history of European domination in the region. Freedom from
external control and an intense interest in and involvement with politics are
pan-Caribbean cultural elements (Stoffle, 1986).
e MOE! - There is also a conflicting tendency by many islanders to look
externally for solutions to local problems (while simultaneously resenting
foreign intervention or assistance). This is due partly to the colonial history of

enforced dependence and partly to the nature of high populations on small

 

islands, in which all the resources needed by inhabitants cannot be provided
locally.

0 MW - There is a need among islanders to be engaged in a
variety of activities to reduce risk and ensure survival under severe constraints
(Burpee and Morgan, 1986; Comitas, 1973).

0 W - This strategy maintains some production every year,
compared to the strategy of cash crop production, which is generally
characterized by instability, with high production in some years and none in
others.

e W: - Multiple, complex kinship/community networks are
maintained to reduce risk, by sharing individual good fortune with a maximum
number of family/community members (Rubenstein, 1987).

0 mjgmflgn - This is the traditional, ultimate response to extremely limiting
environments. Caribbean emigrants are usually the healthiest. best educated

and most highly motivated citizens. causing "brain drain" and slowed economic

1 30

development at home (Pastor, 1985).

To summarize. the significance of these human cultural factors is that any
changes proposed as solutions to people-environment problems in Buen Hombre
must foster sovereignty, but provide apprOpriate support, maintain occupational
multiplicity, increase production through increasing diversity and protecting stability,
foster equitable distribution of production to avoid community divisiveness, and
generate local or regional income-producing activities to prevent migration abroad or

to already overburdened cities.

V. Relationships between ecosystems and human activity systems
In Buen Hombre, human survival is tied to interdependent relationships and

complex balances between terrestrial, marine and human ecosystems. As an
example, fishing adds stability to village subsistence systems by increasing diversity
of food and income sources. However, when rough weather. overfishing by
outsiders, failure of boat motors or turbulent sea conditions curtail fishing, villagers
depend on agricultural produce or agricultural ”savings accounts" in the form of
farm animals. On the other hand, when crops fail, villagers increase fishing
activities, hunt forest fowl, take advantage of external social support networks, etc.

Another example of the complex human-ecosystem balance in coastal areas
like Buen Hombre concerns the mangrove ecosystem. During droughts, the
absence of terrestrial runoff to the mangroves results in higher proportions of salt to
fresh water in mangrove swamps. slowing mangrove growth, and causing
extremely low mangrove water levels that restrict mangrove use as fish breeding

and spawning grounds. Alternately, excessive fresh water runoff into new-growth

1 31
mangrove swamps takes away the competitive advantage of slower growing salt-
tolerant, mangrove species over faster-growing non-salt tolerant tree seedling
species. However, once established. mangrove trees grow faster in greater fresh
water concentrations. And without periodic additions of organic matter and
nutrient-carrying clay sediments, nutrient-poor coastal sands slow mangrove
growth. Yet an excess of clay sediments impedes mangrove root aeration and soil
drainage and causes coral reef damage (Hutchings and Saenger, 1987).

Thus, mangroves serve as a checkpoint between marine and terrestrial
ecosystems, regulating coastal physical and biological interactions, providing
biological habitat for birds and insects, fish and shellfish, and adding stability to
human subsistence activity by supporting marine and terrestrial fauna, and by
providing lumber. Changes occurring in either the human activity systems, the
marine or terrestrial ecosystems can affect the mangrove interface and ultimately

the whole system.

VI. The natural resource situation in Buen Hombre

During the last fifty years. two major changes in Buen Hombre have jeopardized
village subsistence activity - one affecting the terrestrial ecosystem and one, the
marine ecosystem. Village reports, verified by regional rainfall records, indicate that
since the 1940's, agricultural production has changed both in terms of the species
planted and in decreasing overall production. Elder villagers tell of "sufficient” rain
prior to the 1940's. Many crops were grown, including bananas and upland
(dryland) rice. Both these crops require an annual minimum of approximately 1,000

mm of evenly distributed precipitation for moderate yields (Da Mata, 1980; Stansel,

1 32
1980; Soto. 1985). These crop rainfall requirements coincide with available
climatic records for the region. which report average annual rainfall amounts of
1,200 mm for an unspecified 7-year period, sometime between 1900 and 1926. as
well as separate estimates of average annual amounts of 1,000 to 1,500 mm prior
to 1941 (Portman et al., 1991).

But since the 1940’s, precipitation has decreased to an average of 600 to 700
mm per year (Portman et al, 1991), making cultivation of bananas and rice. as well
as many other crops, impossible under rainfed conditions. During the period of this
study, the region underwent a four-year drought. Whether or not the higher annual
rainfall of the early 1900's will return, is debatable. According to Huke (1976), the
period between 1890 and 1945 was the most benign period for world climate in the
last thousand years. It encouraged humans to extend cultivation into areas that
were previously beyond the outer limits of production.

Cuban immigrants settled the village of Buen Hombre at the beginning of the
benign period in 1897. By 1950, when precipitation levels in Buen Hombre had
gone from marginal to unacceptable for rice and bananas, villagers began cultivating
species requiring less water, such as tobacco, pigeon peas and cotton. Many
villagers expect an increase in precipitation at some point, but the past, not the
present, may be the meteorological aberration.

Thanks in part to possibly erroneous expectations of future climate trends,
village response to recent droughts has been decreased reliance on terrestrial
ecosystems and increased reliance on marine ecosystems. There is no evidence of
a conscious shift among villagers to dryland agriculture as a viable, permanent mode

of production, with the exception of the selection of some drought-tolerant species.

1 33
Under such circumstances, maintenance of healthy reefs as productive fisheries has
become vital to village well-being. Unfortunately, a shift to increased fishing is
problematic from several perspectives.

Fishermen from towns and cities east and west of Buen Hombre have been
encroaching on local fishing grounds since before 1985, using large nets with
illegally small netting to catch relatively profitable shrimp. Though Buen Hombre
reef systems are healthier than reefs directly to the east and west, the chinchorro
nets have damaged marine vegetation and decreased fish and shellfish populations
by entrapping the youngest and smallest of many fish and shellfish species. By
1987, populations of certain species were severely diminished or had disappeared
entirely. Although the degradation was reversed, at least temporarily, through an
intervention effort in 1993, the productive capacity of these reef and mangrove
ecosystems appears to be easily overstressed.

The second major factor that may jeopardize village subsistence activity,
specifically village fishing activity, is related to a 1990 government edict declaring
the northwest coast between Puerto Plate and Monte Cristi a tourist zone (Dr. J.
Serulle, personal communication). Local sources predict construction of a coastal
access highway within approximately ten years (Ing. R. Serulle, personal
communication). Beyond the possible negative short-term impacts of mangrove
destruction and increased human activity resulting from this declaration, there is an
additional long-term factor with potential to affect local coastal ecosystems
adversely. Global warming has been predicted. and its effects include rising sea
levels. differential ocean warming. stronger storms, and increased, harmful

ultraviolet radiation in equatorial regions (Weber. 1993b). These changes are

134

expected to threaten existing tropical reef systems worldwide.

CONCLUSIONS

Significant findings of this initial analysis of the Dominican coastal district of
Buen Hombre include the following:

0 Due to the combined factors of isolation, low rainfall, low population, lack of
potable water, and conservation-conscious villagers, local reef and mangrove
ecosystems are currently biologically diverse and productive, unlike degraded and
deteriorating coastal ecosystems in the remainder of the island of Hispaniola.

0 Local terrestrial ecosystems include a diverse mix of trees and plants
(adapted to local climate and soils) within diverse landscapes.

0 Diversity in subsistence production depends on vitality and diversity in a
continuum of near-shore marine to near-shore terrestrial ecosystems.

0 Stability of village subsistence production depends on some measure of
success in both fishing and farming activities. Neither activity alone is sufficient for
survival under significant perturbations to either relevant productive ecosystem.

O Districtwide, population has doubled over the two decade period beginning
about 1960 and was accompanied by shifts in land under moderate and high
intensity land use.

0 Village agricultural production of moderately fertile entisols and inceptisols
has recently been constrained by recent droughts and has resulted in out-migration
of non-fishing, farming-only families.

0 Illegal net fishing by ”outside” fishermen has caused visible harm to coastal

reef flora and fauna populations in Buen Hombre.

135

O Socio-cultural, anthropological, economic, historical and political factors, as
well as eloquently-stated opinions by village leaders, indicate the necessity of village
involvement and/or leadership in any further research and development efforts.

These findings indicate that in Buen Hombre key relationships between humans
and their most economically productive ecosystems are threatened by increased
population, increased human activity, the vagaries of local weather and most likely
global climate change, as well. These findings also suggest two areas where a few
key changes have the potential to make a significant positive impact on the
productivity, stability, equitability and sustainability of human-ecosystem
interactions:

0 With training provided by local agricultural scientists in simple techniques of
experimental design, theory and statistics (as has been done successfully in Bolivia
and Ecuador by Ruddell and Beingolea (1995)), villagers could evaluate and test
low-input. sustainable dryland agronomic techniques for local use.

0 A mariculture project involving ”farming" of non-aggressive shellfish and
algal food supplies in sea cages could provide subsistence and market production.
Villagers have expertise in this technology (Stoffle, 1986), readily available markets,
and an operating fishermen’s association for oversight and leadership, but lack
loans/funding for initial costs.

These improvements are recommended in response to specific local conditions:
previous and potential climate change, increased human pressure on coastal
ecosystems and difficulty of villagers in meeting basic survival requirements. Taken
into account are issues of sovereignty, dependency, occupational multiplicity,

diversity and stability of production, sustainability of ecosystems, equitability,

136
income generation and empowerment.

In the final analysis. though, successful improvement of the situation in Buen
Hombre will depend on the ability of villagers. scientists and policy makers to agree
on both the nature of the problem and on what constitutes improvement, as well as
their ability to evaluate and test the solutions they propose. The National Research
Council (1993) has stated that worldwide, any unmanaged ecosystems will be lost
through overuse. In cases like Buen Hombre, where human activity systems are
extensively and intricately involved in complex, dynamic local ecosystems, the
participatory-systems model has potential as an effective vehicle for improvement

and change.

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139

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Ruddell, Edward D. and Julio Beingolea. 1995. Towards farmer scientists. lLElA
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140
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141

Table 1 . Quality of drinking water in Buen Hombre district, sampled April 15, 1992

 

 

 

Chemical Las Canas Las Huberas Unacceptable

Element or Buen Hombre lagoon lagoon levels for

Compound well (mg L") (mg L") (mg L") drinking
water (mg L")

NO, (nitrate) 12.3 ND‘ ND > 10

Cl (chloride) 1 908 10 1 3 > 250

FI (flouride) 1.1 0.1 0.1 >4.0

Hardness 1945 132 95 > 250

as CaCO3

Fe (iron) ND ND ND >O.5

so3 (sulfate) 916 ND ND > 5002

Na (sodium) 1043 ND ND > 250

Ca (calcium) 194.5 40.6 28.3 ---3

Mg (magnesium) 277.0 7.5 5.7 «-

Pb (lead) 0.024‘ 0.004 ND

pH 7.0 7.1 7.2

 

1Not detectable. ’T he EPA (Environmental Protection Agency) is considering a
sulfate limit of 400 to 500 mg L". 3Non-toxic element, water softening may be
appropriate. ‘Unacceptable Pb level for municipal well.

142

 

Table 2. Land use classification system for Buen Hombre (based on CEUR-
CARTEL system) (Source: St.-Pierre, personal communication)
1. HUMAN SETTLEMENTS

1.1 W
1.2 W: Villages, towns, etc.
2. AGRICULTURE

2.1

2.2

2.3.1

2.3.2

2.3.3

2.4

2.5

2.6

2.7

MW: Typical subsistence cultivation on
small landholdings, generally intercropped; minimum of 50% land
area in production. No irrigation equipment identified.

MW: Crops in constant production. Irrigation

equipment identified.

W: Small cultivated parcels surrounded
by forest. At least 75% of area is forested.

WW: Intensified
use of soils, the fallow cycle has been shortened and does not
allow re-establishment of forest. At least 75% of area is covered
with bushy vegetation.

WW: Cultivation cycles are

shortened, fallow is reduced to less than 5 years, and bushy
vegetation cannot re-establish. At least 75% of total area is
covered with pasture/grazing lands.

W: Coffee, cocoa, coconut are found in
forested patches, often interspersed with human settlements. Also
found are lengthwise gullies of running water.

WWW: Export crops.
managed with industrialized technology.

Em: All types of terrain are in production, landholdings greater
than 8 hectares.

ngg: Predominantly monoculture, different field sizes and forms of
production.

143

Table 2. (Cont'd.)

 

2.8

W: These fields are used only for sugar cane production: large-
scale production.

PASTURELANDS
3.1 MW: Areas that have been cleaned, developed,

maintained for grazing, normally fenced.

3.2 MW: Areas that have not been cleaned for
cultivation or grazing and show no evidence of being maintained.
Usually unfenced and found within areas that contain patches of
bushland and/or forests. Used extensively by cattle ranchers in the
mountains, with an initial fallow period. Less than 25% covered
by bushy vegetation.

3.3 W: Generally natural, permanent pasture with
approximately 25% scattered trees (e.g., palm trees).

FORESTS

4.1 mm: Canopy cover of 50% or more, does not include
cultivated perennials. Includes coniferous, mixed and dry forests.

4.2 magmas: Coastal woodlands.

4.3 W: Land with a wide variety of
bushes and small trees. Normally this type of tree has little or no
commercial value. Generally used for household consumption,
such as for firewood. Usually natural vegetation in the process of
recuperation. Canopy cover greater than 50%.

WATER
5.1 W: Includes rivers, lakes, lagoons, dams. Natural or
man-made.

WETLANDS, LAND SUBJECT TO FLOODING: (Swampland, marshes)
Can be connected to the sea. Frequently associated with lowlands.
Aquatic, water-tolerant vegetation as a result of flat, lowlands.

BARREN LANDS: (Includes saline soils, highly eroded areas, etc.) Areas
barren of vegetation, not including land devastated by mines.

OUARRIES, MINES: Includes rock/mineral deposits, areas where
vegetative cover and soils removed to expose rocks, limestone, bauxite.

144

Table 3. Land use distribution, Buen Hombre District: 1958, 1966, 1984
(Source: St.-Pierre, unpublished data)

 

 

 

1958 1966 1984
TYPE OF LAND USE km2 % krn2 % km’ %

Non-irrig. agriculture' 13.2 32.4 11.9 29.0 9.3 22.6
Temp. agric./scrubland 0.1 0.3

Temp. agric./pasture 0.8 1.9 1.2 2.9 3.7 9.0
Perennial tree crops 0.3 0.6
Natural pastureland 1.2 3.0
Pastureland with trees 0.9 2.2 0.1 0.2
Forest 25.6 62.6 24.7 60.4 25.3 61.8
Mangroves 0.9 2.3 0.9 2.3 0.9 2.2
Bushy vegetation 0.2 0.6 1.0 2.5

Wetlands 0.2 0.4 0.2 0.4 0.2 0.5

 

'See Table 2 for complete descriptions of land use categories.

Table 4. Type of land use by general category, Buen Hombre District (Source: St.-
Pierre, unpublished data)

 

115311651935

 

Type of land use (km’) (km’) (km’)
Farmland, non-irrigated 13 12 9
Forest 26 25 25
Pastureland, grazing lands 1 1
Grassland with trees 0 1 0

Mangroves 1 1 1

 

145

Table 5. Population for Buen Hombre District“, 1935-1981 (Source: Castillo,
National Census, Dominican Republic, 1936,1951 , 1961 , 1971 , 1982)

 

 

Population 1935 1950 1960 1970 1981
Males 141 1 55 390 No data 739
Females 125 123 320 No data 587
TOTAL 266 278 710 1,053 1,326

 

“Buen Hombre Census District includes Buen Hombre, Los
Conucos, Las Canas and Las Brigidas (Figure 3).

146

Table 6. Degree of intensity of land use, Buen Hombre District: 1958,
1966, 1984 (Source: St.-Pierre, unpublished data)

 

 

1.9.53 4 193.6 1.933
Degree (hectares) (hectares) (hectares)
Low 2,713.76 2,677.29 2,642.68
Moderate 78.37 213.24 517.60
High 1,299.47 1,201.06 931.33

 

Table 7. Degree of erosion risk potential, Buen Hombre District: 1958,
1966, 1984 (Source: St.-Pierre, unpublished data)

 

 

1_S_53 1.9.6.6 1.9.83
DEGREE (hectares) (hectares) (hectares)
Low 3,282.39 3,360.75 3,360.76
Moderate 147.63 140.34 83.84
High 153.09 169.50 76.55

Very High 508.49 421 .02 570.46

 

147

Table 8. Plant species" * identified by villagers, Buen Hombre

 

 

Family' ‘ " Botanical Name Common
Name
Acanthaceae Justicia sessilis Jacq.“9 Carpintera
Rue/lie tuberosa L.‘ Guaucf
Amaranthaceae Philoxerus vermicularis Verdolaga
(L.) R. Br.° del Mar
Amaryllidaceae Frucraea hexapetala Cabuya
(Jacq.) Urb.°
Apocynaceae Echites umbellata Jacq." Curamaguey
Asclepiadaceae Mate/ea maritime (Jacq.) Guanabanita
Woodson°°
Asteraceae Artemisia domingensis Urb.“9 Altamisa
Mikania papillosa Klatt" Bejuco
Blanco
Parthenium hysterophorus L. " 3" Hierba
Amarga
Boraginaceae Heliotropium angiaspermum Alacrancillo
Murray"6
Brassicaceae Lepidium virginicum L." Matuerso
Chenopodiaceae Chenopodium ambroisioides Caledonia
L.'458
Euphoribiaceae Jatropha gossypifolia L."° Tuatua
Chamaesyce hirta L.‘ Malcasa
Lamiaceae Leucas martinicensis (Jacq.) Molenillo
R. Br.°2
Leguminosae- Senna angustisiliqua (Lam.) Carga Agua
Caesalpinioideae Woodson & Barneby'”
Cassia occidentalis L." Bruca
Liliaceae Aloe vera (L.) Burm. f.” Sébila

Table 8. (Cont'd.)

148

 

Malpighiaceae

Malvaceae

Nyctaginaceae

Orchidaceae

Papaveraceae
Plumbaginaceae

Poaceae

Rubiaceae

Scrophulariaceae

Solanaceae

Verbenaceae

Stigmaph yllon periplocifolium
(Desf.) Juss.6

Abutilon abutiloides (Jacq.)
Garcke'1
Gaya occidentalis IL.) HBK.’

Boerhaa via scandens L. "

Vanilla barbella ta Rchb. F.‘

Argemone mexicana L.’1
Plumbago scandens L. "

Cenchrus spp.’

Digitara decumbens Stent’
Eragrostis spp.’2

Panicum maximum Jacq.3

Spermacoce assurgens
Ruiz & Pavon ‘

Capraria biflora L.°‘5
Scoparia dulcis L.‘

Datura inoxia Miller'1

Lycium americanum Jacq."
Salanum americanum Miller'3
Salanum polyacanthum Lam.‘

Lanata sp."‘°
Lanata camara L.°
Stach ytarphe ta jamaicensis L.‘

Bejuco de
Cascarita

Escoba
Blanca
Escoba Dulce

Bejuco de
Lombriz

Cardo Santo
Pega Pollo

Cadillo
Pangola
Grama
Hierba de
Guinea

Juana La
Blanca

Feregosa
Cancharagua

Cornicopio
Gri Gri
Hierba Mora
Doncella

Oreganillo
Dona Sanica
Verbena

 

*Plant species collected in Buen Hombre, and subsequently identified by Dr.

Thomas Zanoni, National Botannical Gardens, Santo Domingo

"Botanical references: Geilfus, 1989: Liogier, 1974: Weniger and Robineau, 1988.

 

 

 

149

Table 8. (Cont’d.)

 

* * " The Code of Botanical Nomenclature was adhered to for family names (those
with -aceae suffixes) of plants in this table, except in the case of the Fabaceae
family. For this family, the traditional name of Leguminosae was used to emphasize
the nitrogen-fixing capabilities of certain species.

Numeric superscripts indicate ecozones where specimens were encountered
(species may occur in other ecozones):
'Cleared agricultural field ’Edge of agricultural field
3Fallow field ‘Sandy coastal, or beach, zone I5Coastal salt flats
aFoothills, scrub vegetation 7Roadside “Household yard/garden
“Mountain

150

Table 9. Tree species“ identified by villagers, Buen Hombre

 

 

Family Botanical Name Common
Name
Anacardiaceae Anacardium occidentale L.9 Cajuil
Annonaceae Annona muricata L.” Guanabana
Annona squamosa L. Andn
Boraginaceae Cordia curassavica Juan Prieto
(Jacq.) R. & S.
Cordia laevigata Lam. = Muileco
Cordia nitida Va hl°
Burseraceae Bursera simaruba = Bursera El Almacigo
gummifera = Elaphrium simaruba9
Cactaceae Cereus jamacaru DC.267 Cayuco
Harrisia divarica ta (Lam.)° Yaso
Nopalea cochenillifera Tuna de
(L.) Salm-Dick” Espai’la
Capparaceae Capparis flexuosa L.‘ Mostazo
Combretaceae Conocarpus erectus Mangle Prieto
(Vahl) R. & S.‘5
Laguncularia racemosa (L.) Mangle
Gaerth. f.‘ Blanco
Euphorbiaceae Jatropha Curcas L. Pinon de
Leche
Ja tropha multifida L.“ Pinon
Extranjero

Leguminosae
Leguminosae-

Caesalpinoideae

Leguminosae-
Mimosoideae

Diph ysa r'obinoides5
Parkinsonia aculeata L3”
Peltophorum berteroanum Urb.2
Tamarindus indica L.“

Acacia farnesiana IL.) Willd."’
Prosopsis juliflara (Sw.) DC
Samanea saman (Willd.) Merrill"

Palo Amarillo

Cambron
Guatapanal
Tamarindo

Aroma
Bayahonda
Saman

Table 9. (Cont'd.)

151

 

Leguminosae-
Papilionoideae

Liliaceae

Malpighiaceae

Malvaceae

Meliaceae

Moringaceae

Myrtaceae

Oxalidaceae

Palmaceae

Phytolaccaceae

Polygonaceae

Punicaceae

Rhamnaceae

Rhizophoraceae

Adenanthera pa vonia L.9
Rh ynchosia pyramidalis
(Lam.) Urb.’

Sesbania grandiflora (L.) Pars.8

Yucca aloifolia L.”
Bunchosia glandulosa
(Cam) L. C. Rich”
Malpighia domingensis Small°
Abutilon american L.“
Trichilia pallida Sw.
Azadirach ta indica =
Malia azadirach ta8
Moringa oleifera Lam.8
Cryptorrhiza haitiensis Urb.‘
Eucalyptus deg/up ta"
Eugenia foe tida Pers.’
Eugenia glabrata (Sw.) DC.9

Oxalis barrelieri L.

Cocco thrinax argentea
(Lodd.l Sarg.’

Petiveria alliacea L.
Coccoloba diversifolia Jacq.“
Coccoloba uvifera (L.) L.‘
Punica grana tum L.’
Krugiodendron ferreum

(Vahl) Urb.”
Ziziphus reticulata (VahII‘

Cassipourea obtuse Urb.’

Coralillo
Pega Palo

Gallito
Jenco
Cabra

Cereza
Cimarrona

Yerba Blanca
Palo Amargo
Nim

Libertad
Canelillo
Bagras
Escobdn
Arraijan

Vinagrillo

Guano

Anamu
Uvero
Uva de la
Playa
Granada
Ciguamo

Sopaipo

Parrilla

Table 9. (Cont’d.)

152

 

Rosaceae
Rubiaceae

Rutaceae
Sapindaceae

Solanaceae

Staphyleaceae

Ulmaceae

Zygophyllaceae

Cra taegus mexicana‘
Antirhea lucida
(Sw.) Benth. 8: Hook.‘
Chiococca alba (L.) Hitchc.’
Exostema caribaeum (Jacq.)
R. 81 S.9
Ste vensia buxifolia Poit.‘

Amyris elemifera L.’
Melicoccus bijugatis Jacq.‘
Solanum umbella tum Mill.‘
T urpinia panicula ta Vent.”

Ph yllostylon brasiliensis
Ca pa nema”

Guaiacum officinale L.“

Manzanilla
Aguacatillo

Timaque
Ouina

Cuabilla
Guaconejo
Limoncillo
Friega Platos
Violeta

Baitoa

Guayacan

 

*Botanical references used: Geilfus, 1989: Liogier, 1974; Weniger and Robineau,

1988.

Numeric superscripts indicate ecozones where specimens were encountered
(species may occur in other ecozones):
‘Cleared agricultural field 2Edge of agricultural field 3Fallow field ‘Sandy coastal, or

beach,zone

sCoastal salt flats °Foothills, scrub vegetation 7Roadside °Household yard/garden

9Mountain

153

 

 

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Figure 4. Graphic representation of combined factors of slope, land use and
vegetative cover, used to determine erosion risk potential

maul-cow----

--I...I-mun.

-----_--—-

157

 

LAND USE: 1958
Buen Hombre

  
    
   
       

 

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LAND USE: 1966

Buen Hombre

  

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LAND USE: 1984
Buen Hombre

 

 

 

 

Figure 5. Buen Hombre land use: 1958, 1966 and 1984. (Modified and redrawn
from unpublished CEUR-CARTEL data provided by St.-Pierre)

158

 

LAND USE INTENSITY: 1958

Buen Hombre

 

 

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I 1. more“
I 1. It...

 

 

 

 

 

 

 

LAND USE INTENSITY: 1966
Buen Hombre

 

 

 

 

 

 

 

 

 

LAND USE INTENSITY: 1984
Buen Hombre

 

 

 

 

 

 

 

 

Figure 6. Buen Hombre land use intensity: 1958, 1966 and 1984. (Modified and
redrawn from unpublished CEUR-CARTEL data provided by St.-Pierre)

159

EROSION RISK: 1958

Buen Hombre

 

      
 

    
 

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EROSION RISK: 1966
Buen Hombre

 

 

 

 

 

 

 

EROSION RISK: 1984

Buen Hombre

 

 

 

 

 

Figure 7. Buen Hombre erosion risk potential: 1958, 1966 and 1984. (See Figure 3
for factors used in category designations.) (Modified and redrawn from unpublished
CEUR-CARTEL data provided by St.-Pierre)

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SUMMARY AND CONCLUSIONS

This research addresses the use of vegetative cover in harsh tropical
environments. similar to those found in the semi-arid farming-fishing village of Buen
Hombre in the Dominican Republic. Three major constraints to the introduction and
use of vegetative cover in tropical subsistence agriculture are -- technical agronomic
constraints. socio-economic constraints and ecological constraints. A key technical
constraint for aerial broadcast seeds is species selection for limiting conditions of
high temperature and insufficient water at the soil surface. Therefore, the first goal
of this research was to develop a rapid screening technique in the laboratory to
identify species that would be suitable for such environments. The second goal
was to conduct field tests of species showing promise in growth chambers and
evaluate the effectiveness of the rapid screening procedure as a selection tool.

Laboratory germination experiments, which were conducted over a wide
range of temperatures and water potentials. characterized boundary conditions of
germination for eight tropical species and were reasonably good at predicting
germination response in the field. Subsequent field tests identified six species with
potential for the Dominican Republic field site -- jack bean, Iablab bean. sorghum,
sunnhemp, tepary bean and tropical velvet been.

The laboratory technique worked well, and with some modifications, the rapid

screening technique could be adapted for use as an on-Iocation screening procedure

162

163

at small research institutes in the tropics. (Large, costly growth chambers would be
replaced by small, inexpensive, simply designed ones for germination studies.) In
another modification, the negative effects of biotic interactions in field studies could
be avoided or decreased by overplanting, insecticide applications or by conducting
large-scale field studies lrelegating biotic interference to edges).

Assuming that the technical constraints above are surmountable, the next
level of constraints to the use of vegetative cover in subsistence agriculture include
sociological, cultural and economic factors. Initial survey research indicated that in
this village, mean annual income of responding farmers was $381 or less,
subsistence conditions for families in terms of food. health and nutrition were
severely limiting and villagers were very open to the possibility of change. Current
constraints to the use of vegetative cover include lack of knowledge and expertise
on use and management within the village, lack of previous experimentation by
village farmers, lack of access to seeds and possible labor constraints during certain
months of the year. There appear to be no cultural norms against the use of beans
of different colors in the diet. though incorporation of leafy greens might be
problematic, as they are considered a condiment, rather than a crucial part of the
diet. Food-producing vegetative cover planted in the off-season has great potential
to alleviate food shortages and malnutrition. it also has potential to diversify and
increase subsistence production, increase villagers' self-sufficiency and reduce
emigration. Villagers appear eager to adopt this technology. If given some
assistance, in my opinion, villagers are capable of conducting both simple selection

studies and larger field-scale experiments. evaluating results and fine-tuning this

1 64
technology for their environment. Ultimately, the effects of increased use of
vegetative cover in this village would be better land management, modest increases
in productivity and greatly increased ecological stability.

From an ecological perspective, constraints to the use of this technology are
related to the interdependence and delicate balance that exists between land-based
and marine-based ecosystems. Pressure applied to one ecosystem (e.g., through
drought or unsustainable fishing by outsiders) results in excessive strain to the
productive capacity of the other. This causes negative consequences within the
ecosystems and for villagers who cannot survive on one ecosystem alone. The
fragile balance between subsistence agriculture, an undependable water supply and
subsistence fishing can be strengthened and stabilized by drought-tolerant
vegetative cover, which would prevent excessive, damaging erosion to mangrove
and reef ecosystems and would relieve some fishing pressure on reefs by providing
an additional food source for villagers. Because change, possibly dramatic change,
is imminent in this region, villagers must improve their ability to manage local
ecosystems.

Strategic directions for the future include combined research and
development in the village, possibly using the participatory-systems model to define
problems, design research, propose solutions and evaluate resulting projects. A
combined project involving the two key ecosystems and their related human activity
systems is recommended: a fish mariculture project (to relieve marine ecosystem
pressure, provide dry season sustenance and increase cash income) with vegetative
cover and mixed-system dryland agriculture project (to provide stable, increased

yields over a longer time period).

165

This recommendation would meet the implicit objectives of the author to
strengthen subsistence production and stabilize the local environment. It would
also be consistent with the high priority placed by villagers on income generation.
Future research needs to address rates of change, ecosystem management by
villagers, indicators villagers could use to monitor ecosystem change, issues of
adoption of sustainable technology and use by villagers, as well as agronomic
issues (surface and below-surface germination, monocropping versus intercropping
with species of introduced and indigenous vegetative cover, planting times and
labor requirements). Critical to the success of future intervention in this village is

development combined with research and strong village involvement.

APPENDIX I:

BUEN HOMBRE SURVEY QUESTIONNAIRE

166

ENTREVISTAS EN BUEN HOMBRE
BUEN HOMBRE INTERVIEWS

BUENOS DIAS/BUENAS TARDES:
'ME GUSTARIA BACERLE ALGUNAS PREGUNTAB SOBRE AGRICULTURA, LAS

PLANTAB, LOS ANIMALES Y SU VIDA AQUI EN BUEN HOMBRE. aTIENE

USTED TIEMPO DE HABLAR CONMIGO Y RESPONDER ALGUNAS PREGUNTAS?
NO NECESITA DARME SU APELLIDO, ASI SUS RESPUESTAS SERAN

CONFIDENCIALES. LAS RESPUESTAS SERAN COMBINADAS CON LAS

RESPUESTAB DE OTRAB PAMILIAB, LO QUE RACE DIPICIL IDENTIFICAR EL

ORIGEN.

(GOOD MORNING/GOOD AFTERNOON: I WOULD LIKE TO ASK YOU SOME
QUESTIONS ABOUT AGRICULTURE, PLANTS, ANIMALS AND YOUR LIFE HERE
IN BUEN HOMBRE. DO YOU HAVE A LITTLE TIME TO TALK TO ME AND I
ANSWER SOME QUESTIONS? I WILL NOT ASK FOR YOUR LAST NAME, SO
YOUR REPLIES WILL BE KEPT CONFIDENTIAL. YOUR ANSWERS WILL BE
COMBINED WITH ALL THE OTHER FAMILIES AND WILL NOT IDENTIFIED.)

IDENTIFICACION DE LA ENTREVIBTA (INTERVIEW IDENTIFICATION)

 

Nunoro do In ontrovista (Interview i)

 

Hombre del ontrevistador (I’vwr’s name)

 

Pocba do 1: ontrovista (Date of i'vw)

167

C1. aCual as an nombra? (What is your name?)

 

C2. aCuantos afios tiana Ud.? (Age?)

C3. Baxo (Sex)

 

aQuian mas viva aqui? Bolamanta tiana qua dacirma sus nombras
tianan, sus adadas, su saxo y qua ralacion con ustad. (Who else
lives here? Just tell me their first names, ages, sex and how
they are related to you.) (LLENE LAB RESPUESTAS EN LA CAJA

ABAJO.)
C3. aNombra? (First name)
C4. aCuantos anos tiana (an qua aio nacio)? (Age)

C5. Baxo (Sex)

cs. aQua ralacion tiene el/ella con Ustad? (How is he/she related
to you?)

C7. aAlguian mas? (Anyone else?) 80 SI (RBPITA C3 - C7)

C8. anay otras persona: tamporalmanta ausanta, pare qua
ragrasaran a vivir aqui pronto, parsonas qua no tianan case an
otro lugar? (Are there others who are away for awhile, but will
return to live here soon, people who do not have a main home

anywhere else?)

NO SI
CONTINUE A 58: al/alla un miambro da la familia, tambian?
C9 (Then he/she is really a part of your family,
too.)

(REPITA C3 - C7 Y ENTRE EN LA CAJA ABAJO.)

Nombra Afio Nacio Ralacion con
Primaro o Edad Baxo Informanta ahgricultor? azsposa?

 

 

168
BUEN HOMBRE INTERVIEW

ANONYMOUS COVER SHEET
(To replace original cover sheet after interviewing)

Interview Number

 

Name of Interviewer

 

Date of Interview

 

Anyone listed, but temporarily away?

1. No
2. Yes

Relisting of this family only, with farmer first and
relation to farmer. (Put youngest children laSt.)

Relation Check in row if:

Line
Informant Farmer Spouse

Number Age Sex to farmer

 

1 Farmer

 

2

 

 

 

 

 

 

 

 

10

 

ll

 

 

 

 

12

 

 

 

 

 

169

ENTREVISTA oz acnrcanroa
(FARMER’S INTERVIEW)

9.1. 533 ad. un miambro da la asociacion da agricultOIOS? (Are
you a member of the agricultural association?)

 

 

1. NO 5. SI

 

 

 

 

 

 

a o cultiva una parcala de tiarra?

9.2. adiana Ud. suLpropia finc
e a parcel of land?)

(Do you have your own farm or do you cultivat

 

 

1. NO 5. SI

 

 

 

 

VAYA Ni PIN

9.2a. aCuantas parcalas tiana Ud.?
have?)

(How many plots do you

 

I”.

1. UNO 2. DOS 3. TEES (. CUATRO S. CINCO O MAS
l_______, L_____——
9.3. 5Como obtuvo la tiarra
farmland?)

 

 

 

 

 

 

 

 

 

 

qua cultiva? (How did you obtain your

 

 

cual as al tamano total da sus parcalas? (In

9.4. aEn taraas,
r all your plots together?)

tareas, what is the total size 0

 

9.5. aSon suyas todas las parcalas qua cultivo asta ano? (Do you
own all the plots you farmed this year?) '

 

 

1. NO 5. SI

9.5.? (81 38 TERRATENIENTB) aAlquila algunas
parcalas a otras parsonas? (IF A LANDOWNER: Do you
rent any of your other land to other people?)

 

 

 

 

 

 

 

1. NO 5. SI

 

 

 

 

 

b
9.5b. aCuantas taraas alquila Ud.?

 

9.5:. aPaga al alquilar an pasos,
parta da su cosacha, animalas o

algo mas?

 

varn a 9.6 varn a 9.7

 

170

9.6. (BI CULTIVA PARCELAB QUE PBRTENBCEN A OTRA PERSONA) D:
0d. algo al duano an intarcamhio por cultivar 1a tiarra?

(IF RESPONDENT CULTIVATES LAND BELONGING TO SOMEONE ELSE: Do
you give anything to the landowner in exchange for farming

 

 

 

 

 

 

 

 

 

 

the land?)

1. NO 5. SI
9.6*L Paga an pasos, da parta da la cosacha,
animalas o algo mas? (Do you pay cash, give
part of your harvest, animals or something
else?)

I! 1. neon] [2. coascm I; mmzs B.ALGO m
\ ,

 

 

 

 

 

 

 

 

9.7. Son sus tiarras, 0 Ian tiarras qua 0d. cultiva, planes 0
cuaatas o anhos? (Is your land flat, sloped or both?)

 

 

 

1. PLANAB 2. CUESTAS 3. AMBOB

 

 

 

 

 

 

 

 

 

9.7a. Aqui‘hay cuatro éfiadroa da cuaatas con
difaranta cantidadaa da inclinacion. aPuada
moatrarna cual sa paraca mas a la mayoria da las
cuastas an su tiarra? (Here are 4 pictures of
slopes with different amounts of steepness. Can
you tell me which is like most of the slopes on
your land.)

5. MRS QUE 25*

a. mo (upliqua) :

 

 

 

 

 

\V'

Ahora voy a hacarla algunas praguntaa acarca da los cultivoa qua
ustad sianbra.

9.8. LCuando hay lluvia, cualaa cultivos sianbra Dd. usualnanta?
(When there is rain, which crops do you plant?)

! dal Nombra dal I dal no-hra dal

 

 

171

9.8a. ahlguna mas? (are there more?)

 

 

 

 

9.0b. acuando no hay nucha lluvia, cualas cultivos aiambra
04.? (When there’s not much rain, what crops do you plant?)

 

 

 

 

 

9.9. aCualaa oultivoa paracan craoar major aqui an Buan Hombra
ouando hay lluvia? (Which crops seem to grow better here in Buen
Hombre when there is rain?)

 

 

 

 

9.9a. (81 EA! CULTIVOB SSCRITO an 9.9 ARRIBA) aPorqua pianaa qua
astoa oultivoa oraoan major qua otroa an Buan Hombra? (Why do you
think these crops grow better than other crops in Buen Hombre?)

 

 

 

 

 

9.9b. a! cuando no hay nuoha lluvia, cualas cultivoa paracan
craoar najor an Buan Hombra? (And when there isn't much rain,
which crops grow better in Buen Hombre?)

 

 

 

 

Q.9c. (BI KAY CULTIVOB BBCRITO EN Q.9b ARRIBA) {Y porqua piansa
qua astoa cultivoa oraoan major cuando no hay nucha lluvia an
Buan nolbra?

 

 

 

 

9.10. Leia-pro sianhra 0d. aus oultivoa al nismo tialpo dal afio o
oanbia al tialpo da Ila-bra? (Do you always plant your crops at
the same time of year, or do you change the time of planting?)

 

 

 

 

 

[1. :1. ratio umo s. ovum: umo a. mo

 

 

 

 

 

'172

9.10a. aPorqua?

 

 

 

9.11. asiambra los nismos cultivos an las mismas parcalas cada
ano, o cambia loo cultivos qua aiambra an cada parcala? (Do you
plant the same crops in the same fields each year, or do you
change the crops that you plant in each field?)

 

[1: nos xrsxoa cunrxvoii][§:nxrsnsumns conrzvoa].[§. 01307]

 

9.11A. aPuoda dacirma porqua siambra aus cultivos asi? (Can
you tell me why you plant your crops this way?)

 

 

9.12. asianbra Dd. solamonto un oultivo por parcala o oiambra mas
do un cultivo por parcala? (Do you plant only one crop in a
field or more than one crop in the same field?)

 

1. an cunrrvo][s. MAB our on cunrrvo_]|_7. omno ]

9.12a. LPorqua sianbra 9.12b. aporquo loo siambra juntos?
un solo cultivo?

 

 

 

 

 

 

 

 

9.12c. 1Canbia algunas vaoas la
conbinacion do cultivos? (Do you
change the combination of crops

somet' es?
d. a orquo?

0.12

 

 

 

 

9.12o. aCualao cultivoo
aianbra juntoa? (Which
crops do you plant
together?)

 

 

 

 

 

 

 

 

173‘

9.13. asianbra todas sus parcolas cada ano o parnito la tiorra a
quadar ariasa algunos anos? (Do you plant each field every year
or do you let the land lie fallow some years?)

[1. arm» can moJ [5. annzo memos mos] La. 01110 ]

9.13a. aCon qua froouoncia as la tiarra oriasa?
(How often is the land fallow?)

 

9.13b. Leo-o dacida 0d. ouando cultivar y cuando
no cultivar? (How do you decide when to cultivate
and when not to cultivate?)

 

 

 

\l/

9.14. Leonaralnanto, an oualas moses dal ano haco astas taraas --
(Generally, in what months of the year do you do these tasks --)

9.14a. linpia los oampos? (clear the fields?)
9.14b. labra al sualo? (till the soil?)
9.14s. dashiarba? (weed?)

9.14d. oosacha? (harvest?)

9.15. 19uo notodos usa Ud. para linpiar los campos antas do
sombrar los cultivos? (What ways do you use to clear land before

planting crops?)

 

 

9.15a. arorqua usa astos notodos para limpiar? (Why do you
clear the land this way?)

 

 

9.15b. zuorlalnanta quian linpia sus oanpos? (Usually, who
clears your plots?)

174»

9.1a. Leo-o cultiva al sualo antos do oambrar sanillas? (How do
you cultivate the soil before planting seeds?)

 

 

 

9.16a. arorquo propara los sualos asi? (Why do you prepare
the soil this way?)

 

 

 

9.1ob. Normal-onto, quian labra la tiorra antos do sambrar?
(Usually, who tills the land before planting?)

 

9.16c. aHay alguian mas? (Is there anyone else?)

 

9.17. aCono siambra sus sanillas? (How do you plant your seeds?)

 

 

 

9.17a. aCuando sianbra sus sanillas, qua distanoia hay antro
las sanillas? anay un disano rogular o no? anay surcos?
(When you plant your seeds, what distance is there between
seeds? Is there a regular pattern or not? Are there rows?)

 

 

 

 

9.17b. aHornalnonta, quian siambra las sonillas? (Usually,
who plants the seeds?)

 

9.17o. clay alguion mas qua ayuda? (Is there anyone else who
helps?)

 

9.18. aCono doshiorba sus cultivos -- a lano, con una asada
o do qua otra nanara? (How do you weed your crops -- by
hand, with a hoe or what?) .

 

 

9.18a. arorqua doshiarba an asta Ianara? (Why do you weed in
this way?)

 

 

 

175

9.10b. 1Cuantas vooas duranta la ostacion do crociondo
doshiarba Ud. sus cultivos?

[1. nun vzz][g. 2 vzcss][§. 3 vscss] 4. 4 veers ]

[}. MAB gas 5 vscss "7. NUNCAJ

 

 

9.10s. aUsualnanta, quian doshiarba los cultivos? zAlguion
mas?

 

9.19. 1Cono cosocha sus cultivos?

 

 

 

 

9.19a. aUsualnonta, quian ayuda con la oosacha?

 

9.20. 19ua tipos do tratanionto haco a sus cultivos daspuos do Is
cosacha? (How do you process your crops after harvest?)

 

 

 

9.20. 19uion haco ol tratanianto do los cultivos?

 

9.21. Leo-o al-acana sus cultivos? (How do you store your crops?)

 

 

9.21a. LPor ouanto tianpo duran?

 

 

9.21b. 19uo problolas tiana con almaconaja? (What problems
do you have with storage?)

 

 

 

 

 

 

9.22. aVonda algo do on cosacha?

9.22a. alas o nanos, cuanto dinaro gana do la
cosacha tipioananto an un ano?

 

10

176

9.22b. aDa algo do la cosacha a otras parsonas?
9.22s. aCuanto pionsa as al valor do la

parta do la cosacha qua da a otras
parsonas?

 

9.23. anay tipos difarantas do sualos da tiarra an ol campo qua
labra Ud.? (Are there different types of soils in the fields you
work?

)
9.23a. aruada dascribir los tipos difarantas?
ggglo [1

gualo [2

Sualo t3

 

 

 

 

 

 

Suglo I4

 

9.23b. aCambia sus matodos do labrar o los cultivos qua
siambra do acuardo al tipo do sualo?

9.23s. aComo?

 

 

 

 

VI’

9.24. aAfiada algo al sualo a majorarlo, como astiarcol, hojas,
canizas, plantas muartas o abono? (Do you add anything to improve
the soil, like manure, leaves, ashes, dead plants or fertilizer?)

9. 4a. LQua anada?

L1. ssnsnconj 2. 30.1173] [1 cmzasj [4. 21mm nonsuj

 

 

 

 

 

Ls. nos?) [3. om COBA](Bspacifiqua:)

 

 

 

9.24b. (81 USA A3080) aCuanto cuasta al abono y donda
la compra?

 

 

9.24s. anaca algo mas para protagar o najorar al sualo
an sus parcalas?

 

11

 

177

9.25. aUsa Ud. algunos pasticidas/quimicos para matar
insactos of dashiarbas?

9.25a. aCualas quiniooa usa, y los usa contra los

insactos o para dashiarbar o qua?

 

 

 

 

 

9.25b. Lcuanto ouastan?

 

 

v

9.25. 19ua tipo do aquipo usa para labrar al sualo?

 

 

9.2sa. zoo donda viana astos aquipos -- do vacinoa, do

 

familia o ya los tania o qua?

 

 

 

9.27. annsaya Ud. algunas vooas matodos nuavos do oultivo, como
diforantas matodos do sambrar o dasharbar o nuavos oultivos? (Do
you ever try out new methods of farming, like different ways of
planting or weeding or new crops?)

9.27s. aPuada pansar do un ajamplo do un natodo nuavo
qua uso?

 

 

 

 

 

I,

9.20. aConoca algunos agricultoras quianas ansayan matodoa nuavos
do hacar sus taraas an la finca, o qua pruaban matodos difarontas
do labrar? (Do you know any farmers who try out new ways of doing
their farm tasks, who test different methods of farming?)

m—

9.20a. aQuian?

 

9.29. ariana animalas, como vacas, ovajas, ohivos o pollos?

9.29a. 9ua tipos, y ouantos do oada tipo?

 

 

 

 

[ 12
‘

178

9.29b. 19ua coman, sus animalas, duranto al tiampo do
lluvia?

 

 

 

9.29s. 19ua coman duranto los nosas ouando no hay
lluvia?

 

 

9.29d. aaiambra Ud. algo qua los animalas puadan coaor?

 

 

9.29a. 1Cuando ooapra aliaantos para los animalas,
cuanto ouaatan? '

 

9.29f. aVanda los animalas o cosas qua los animalas
producan, coao huavos o locha?

9.299. alas o manos, ouanto dinaro gana Ud.
an un ano tipioo por sus animalas?

 

9.299. aDa algunos animalas, o cosas producido por los
animalas, a otras parsonas?

m—

9.29h. aCuanto piansa as al valor an pasos do
astas cosas an un afio?

 

9.30. aQuian o quianas on la familia haco las dacisionas para la
finca -- ouando haoar las taraas agrioolas, cuantas saaillas so
siaabran, ouando sambrarlos, atc.?

 

 

9.31. anaooga Ud. plantas silvastraa, utilas, qua oraoan an otros
lugaras?

1.xo

9.31a. aCon qua fraouanoia racoga plantas - cada dia,
una vas por samana, una vas por aaa, duranto ostacionos
aspaoialas o qua?

 

 

 

 

13

 

179

9.31b. aQua tan lojos do Buan Hombra va a racogarlas?

 

 

9.31s. anay algunos plantas silvastros qua Ud.
oonsidara utilas para sambrar oarca do la oasa?

9.31d. aCualas, y porqua son importantas?

 

 

 

9.31a. 13a sambrado Ud. algunas coroa do su
oasa? aCualas?

 

 

 

 

\I/

 

9.31f. aHay plantas silvastras qua son mas importantas
duranta ciartos pariodos dal ano?

9.319. aCualas, y ouando? '

 

 

 

9.31h. arorqua son importantas, astas
plantas?

 

 

 

\V

 

9.32. 181 podria Ud. pudiara saabrar un cultivo qua fuara
parfacto para Buan Hombra, parfaoto para al olima, loo sualos y
los problamas do Duan Hombro, qua caractaristicaa tandria asta
planta? Por ajamplo, podria crooar con auy pooo agua, podria
produoir.aliaantoa para parsonas, animalas o qua piansa?

 

 

 

 

9.33. LPodria dacirmo do donda o do quian obtiana sus saaillas?

 

 

 

9.33a. ariana qua pagar laa saaillas?

14

(9.34 Q33"

180

' i

9.33b. aCuanto cuastan?

 

 

 

 

W

9.34. aIntorcambia algunas samillas o racortos con otros
agricultoras?

m—

9.34s. aQua tipos do samillas o racortos?

 

 

 

9.35. aGuarda algunas samillas do un ano para otro?

9.35a. aCualas?

 

 

Ahora, quisiara hablar un poco do la aducacion do las parsonas an
la familia y dal ingraso familiar.

9.36. aHasta qua grado asistio a la ascuala?

 

9.36a. aCual qua ol ultimo grado do las otras parsonas an la
familia con 16 o mayoras do 16 aios?

Hombra Grado final do ascuala

 

 

 

 

 

 

 

9.37. axas o manos, cual fua su ingraso total on ol afio pasado?

 

9.37a. aCualas fuoron las mayoros fuantas do osta dinaro?

 

 

9.38. 181 cualquiara cosa fuara posibla, qua quisiara Ud. var
para al futuro do su familia?

 

 

 

 

15

181

9.39. a! s1 cualquiora cosa fuara posiblo, qua quisiara var para
al futuro do Buan Hombra?

 

 

 

 

 

 

 

No hay mas praguntas por ahora. Huchas gracias para su tiampo y
su colaboraoion rapondiando a las praguntas.

16

182

0.40. ariene Ud. o tuvo un jardin este ano?

rm: 1

0.40a. Tiene un jardin
en anos cuando hay lluvia?

 

 

 

 

 

 

 

 

 

1. NO

0.40b. aCuales plantas siembra Ud. en su jardin?

0.40c. aCuando hay bastante lluvia, siembra

plantas diferentes que cuando no hay mucha lluvia?
0.40d. aCuales plantas siembra cuando
hay lluvia, y cuales plantas siembra
cuando no hay mucha lluvia?

W
l

 

 

 

0.41. aDurante que moses tiene un jardin?

 

0.42. aComo prepara el sualo en su jardin antes de sembrar?

 

 

0.43. aOuien trabaja en el jardin? aAlguien mas?

 

 

0.44. aAnade algo al suelo a mejorarlo, coma estiercol. hojas,
canizas, plantas muertas o abono? (Do you add anything to improve
the soil, like manure, leaves, ashes, dead plants or fertilizer?)

0.4ka. aoue anade?
1. ESTIERCOL 2. HOJAS 3. CENIZAS 4. PLANTAS HUERTAS

5. ABONO 8. OTRA COSA (Especifiqua:)

 

 

17
Jr

183

0.44b. (81 USA ABONO) gCuanto cuesta el abono y donda
la compra?

 

 

0.44c. aHace e190 mas para proteger o mejorar e1 suelo
en su jerdin?

 

0.45. aUsa Ud. algunos quimicos o pesticides para meter insectos
o deshierbar?

1. NO

0.45a. aCualea quimicoa usa, y los usa contra los
insactos 0 para deshierbar o que?

 

 

 

0.45b. LCuanto cuastan?

 

 

 

0.46. aoue tipo de tretamiento hace a sus plantas despues de la
cosecha? (How do you process your craps after harvest?)

 

 

 

0.46s. acuien haco a1 tratamiento de las plantas?

 

0.47. aComo almecana sus cultivos? (How do you store your crops?)

 

 

0.47s. aPor cuanto tiempo duran?

 

 

0.47b. Laue problemas tiana con almacenaje? (What problems
do you have with storage?)

 

 

 

0.48. avande algo do so cosacha?

[:Jx-«o
0.4: . aflas o manos, cuanto dinero gana de la
coaacha tipicamanta en un ano?

 

 

W

18

184

0.48b. 5Da elgo de la coseche e otres parsonas?

0.4Ec. aCuento piensa es el valor de la

parte de la coseche que de a otres
parsonas?

 

0.49. 5Com que frequencie trabeja en su jardin?

 

 

0.50. aoue es el probleme mas grande que tiene creciendo plantas
en su jerdin?

 

 

 

 

0.50e. aComo treta este probleme?

 

 

 

0.51. aCueles otros problemes tiene creciendo cosas en su jerdin?_

 

 

 

 

0.51a. aComo treta estos problemes?

 

 

 

 

0.52. 451 Ud. pudiera sembrar una plente que era perfecte pare
Buen Hombre, perfecto para el clima, los suelos y los problemes
de Buen Hombre, que ceracteristices tendrie esta planta? Por
ejemplo, podrie crecer con muy poco agua, podrie producir
alimentos para parsonas, enimeles o que piensa?

 

 

 

 

0.53. aPodria decirme de donde 0 de quien obtiene sus semillas?

 

 

 

19

185

0.53a. aTiene que pager las semillas?

0.53b. aCuento cuastan?

 

 

 

0.54. alntercambie elgunes semilles o recortes con otres
parsonas?

0.54e. aoue tipos de semilles o recortes?

 

 

 

 

bf
0.55. aGuarde elgunas semillas de un ano para otro?

mm-

0.55e. aCuales?

 

 

0.56. aHey elgo mas respecto a su jardin que quisiera decirme?

 

 

 

 

0.57. aCuendo hay bastante alimento, cuantas comidas prepare Ud.
cede die?

 

0.58. a? normelmente, para estes comidas, que cosas prepare?

 

 

 

 

 

 

 

0.59. aY cuando no hay mucho alimento, cuantas comidas prepare
pare cada dia?

 

0.60. acne cosas prepare para comer cuando no hay mucho alimento?

 

 

 

 

20

186

0.61. aPrepara elimentos diferentes para los muchechos? (SI SI)
aoue prepare?

 

 

 

 

0.62. aAlgunes veces prepare plantas silvestres que colegio Ud.
pare comer? (SI SI) aCuales?

 

 

 

0.63. aCon que frecuencie tienen enfermededes los muchechos en la
femilie?

 

 

0.64. a? los adultos, con que frecuencia tienen enfermededes?

 

 

0.65. aoue tipo de enfermededes tienen los muchechos?

 

 

 

 

0.66. aQue tipo de enfermedades tienen los adultos?

 

 

 

0.67. aOuien o quienes en la familie hecen las decisiones para la
familia -- cosas como donde gaster e1 dinero, como cuidar los
nines enfermos, cuando arreglerla 1e case, cuando visietar al
medico, etc.?

 

 

 

0.68. 181 cuelquiera cosa fuere posible, que quisiere Ud. ver
para el futuro de su femilia?

 

 

 

 

 

0.69. a? si cuelquiera cosa fuere posible, que quisiere ver para
el futuro de Buen Hombre?

 

 

 

 

 

Huches gracies para su tiempo y su colaborecion repondiendo a les
preguntas.

21

"‘Tlilli'lllllWilli“