WEED CONTROL BY MECHANICAL ENERGY AS
A PRE-EMERGENCE SOIL TREATMENT

BY
(.9,

John Bi Liljedahl

A THESIS

Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Agricultural Engineering
195k

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ACKNOWLEDGEMENTS *

The author wishes to eXpress his sincere thanks to
Dr.'W. M. Carleton, Professor of Agricultural Engineering
who has skillfully and unselfishly supervised the investi-
gation upon which this thesis is based.

He also wishes to eXpress thanks to the other members
of the graduate committee, Dr. A. E. Erickson, Assistant
Professor of Soil Science, Dr. R. T. Hinkle, Professor of
Mechanical Engineering, and Dr. V. G. Grove, Professor of
Mathematics, for their suggestions and guidance during the
investigation.

The author is grateful to Professor A. W. Farrell, Head
of the Agricultural Engineering Department, for a smoothly.
functioning Agricultural Engineering Department which has
offered sthmulating working conditions for graduate study.

The writer sincerely appreciates the financial support
of the Farmers and.Manufacturers Beet Sugar Association of
Saginaw, Michigan for the research grant that made this work
possible. Also special thanks is due Mr. Perc Reeve of that
association for his encouragement and suggestions.

A special note of gratitude is due Dr. Buford Grigsby,
Professor of Botany and Plant Pathology for his invaluable

advice, assistance and cOOperation with many of the tests.

 

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John BYFLiljedahl
candidate for the degree of
Doctor of PhiIOSOphy

Final Examination:

Dissertation: ‘Weed Control by Mechanical Energy as a
Pro-Emergence Soil Treatment

Outline of Studies:

Major Subject: Agricultural Engineering
Minor Subjects: Mechanical Engineering
Mathematics

Biographical Items:
Born: May 20, 1919, Essex, Iowa

Undergraduate Studies: Iowa State College, BSAE, 19h6
Graduate Studies: Iowa State College, MSAE,19h7
Michigan State College, 1952-19Sh

Experience:

l9h1-l9h2 Agent USDA, Bur. Agr. Chem. and Engr., Grain
Storage Investigations, Ames, Iowa.

19h2 Inspector. U.S. Rubber 60., Des Moines Ordinance
Plant, Des‘Moines, Iowa.

l9h2-l9h5 Pilot, Engineering Officer, and Instructor.
U.S. Army Air Force, 1st Lt.

l9h6-l9h7 Instructor, Agricultural Engineering Depart-
ment, Iowa State College, Ames, Iowa.

19h7-19h9 Assistant Professor and Research Assistant
Professor Agr. Engr. and Assistant Manager of College

' Farm Service, Iowa State College, Ames, Iowa.

19h9-1952 Associate ProfessOr and'Research Associate
Agricultural Engineer, Agr. Engr. Dept., University of
Tennessee, Knoxville, Tennessee.

1952-195h Special Research Assistant, Agr. Engr. Dept.
Michigan State College, East Lansing, Mich.

Member of:

American Society of Agricultural Engineers
Gamma Sigma Delta, Agricultural honorary
Sigma Pi Sigma, Physics honorary

The Society of the Sigma Xi, Science honorary

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WEED CONTROL BY'MECHANICAL ENERGY AS
A PRE-EMERGENCE SOIL TREATMENT

By
Q.

,5
John at Liljedahl

AN ABSTRACT

Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements

for the degree of
DOCTOR OF PHILOSOPHY'

Department of Agricultural Engineering
195k

APproved 94/

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John B. Liljedahl

It was estimated that there would have been from two
to three million.man hours of hand labor expended on weeding
and thinning sugar beets in Michigan in l95h.

The best methods known to date could have reduced this
hand labor for weeding and thinning sugar'beets by approxi-
mately no percent, which would leave from one to two million
man hours of hand labor.

Since labor is the most expensive item in the pro-
duction of sugar beets, it behooves agricultural researchers,
and Agricultural Engineers in particular, to help reduce the
peak labor requirement in order that the farmers may not
be as dependent upon transient labor.

One way to reduce the weed pOpulation in the row would
be to sterilize a strip of soil approximately four to six
inches wide in which the sugar beet seed could be planted.

A review of literature indicated that it might be possible
to reduce the weed seed germination by subjecting the soil
to a high velocity impact. The literature indicated that
under certain specified conditions a substantial reduction
in the germination of seeds was obtained by impact.

Based upon the somewhat limited literature available,

a field machine was designed to mechanically process a strip
of soil approximately 3/h inch deep by five inches wide in
the row as sugar beets were being planted. The processing
consisted of feeding the soil into the centerof an impeller
which varied in speed up to 3h00 rpm. The impelhar, which

John B. Liljedahl

was 20 inches in diameter, threw the soil against an impact
plate and from there the soil was directed back on to the
planted seed.

Tests were conducted with the centrifugal machine on
muck soil in the greenhouse and in the field and on mineral
soil in the field.

The greenhouse tests using muck soil showed a signifi-
cant reduction in the weed pOpulation at low speeds of 1500
rpm and a significant increase in the weed pOpulation at
high speeds above 2500 rpm. The field tests resulted in no
significant increase or decrease in the weed pOpulation on
muck soil or on mineral soil. Use of mechanical energy in
combination with herbicides significantly reduced the weed
pepulation in.most of the tests, but the reduction was no
greater than that obtained with herbicides alone.

When the centrifugal machine was used to process
mineral soil and at the same time mix.Krilium 9 with the
soil, a significant increase in the emergence of the sugar
beets was obtained in 1953. In l95h a significant reduction
in emergence was obtained when.Krilium 212 was mixed while
processing the soil.

An impact device was constructed to hammer the soil
while in l/B-inch and l/E-inch layers. No significant
reduction in the weed pepulation was obtained at energy
levels of 60 to 7000 foot pounds per pound of soil.

 

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TABLE

INTRODUCTION . . . . .
The Problem . . . .
The Objective . . .

REVIEW OF LITERATURE .

INVESTIGATION. . . . .
Part I

0

OF CONTENTS

0

0

Functional Requirements
Impeller Design . . .
Complete Machine. . .

Part II

Field Tests in 1953 . .

Mineral Soil Tests. .

Muck Soil Tests
Discussion of 1953 Field T

Part III Greenhouse Studies. .
Centrifugal Machine Tests on.Muck

Impact Device Tests . . . . . .
Discussion of Greenhouse Tests.

Part IV

Design of Centrifugal Field

Machine

Oeie e

Muck Soil Field Tests . .
Mineral Soil Field Tests. .
Discussion of l9Sh_Field Tests. .

Btse

O
O
0

Field TOStB in 195” e e e e e e e e
Changes Made in the Centrifugal
Machine e e e e
Variables in the l95h F

ield Tests

0 O 0

CONCLUSIONS. e . e . e . . . e e e e e . e . . e

DISCUSSION AND RECOMMENDATIONS FOR FURTHER STUDI

APPENDIX 0 O O O O O O O O O O 0

GLOSSARY e e e e e e e e e e e e

REFERENCES CITED . . . . . . . .

OTHER REFERENCES . e .

Field

'0 O-O~. .-

Figure

10
ll

12

13

11L

15
16

LIST OF FIGURES

Schematic diagram of the ENTOLATOR machine made
for controlling insects in wheat and flour. .

Effect of mechanical injury on germination of
baby lima beans e e e e e e e e e e e e e e e

Effect of combine cylinder speed upon the
germination of alfalfa seed . . . . . . . . .

Distribution of germinating weeds in untreated
soil from a sugar beet field. . . . . . . . .

Detail drawing of the soil processing impeller.

Calculated particle velocity normal to impeller
as a function of the coefficient of friction.

Schematic diagram or the 1953 soil processing

machine e e e e e e e e e e e e e e e e e e e
Photograph of the 1953 8011 processing machine.

Close-up view of the right-hand side of the
planter lifted up to show the processed
strip or 3011 e e e e e e e e e e e e e e e e

Rear view of scil preceISing machine showing
rock Ecraen e e e e e e e e e e e e e e e e e

Crusting of Brookston clay loam en'check row
three days after planting e e e e e e e e e e

Crusting of Brookston clay loam on row pro-
cessed at 2600 rpm and approximately one
inch deep e e e e e e e e e e e e e e e e e e

Crusting of Brookston clay loam processed at
1600 rpm and treated with 0.1 percent Krilium

Weed growth on muck soil showing effect of
six different treatments. . . . . . . . . . .

Redesigned soil processing impeller . . . . . .
Photograph of weed growth 12 days after treat.

ments were applied. Greenhouse tests with
centrifugal machine on muck soil. . . . . . .

Page

10

ll

14
18

20

22

23

28

28

29

32
35

38

Figure

17

18

19

20

21

22
23

25

26

27
28
29
30

31
32

33

LIST OF FIGURES Continued

Page

Scatter diagram of number of grass and broad-
leaf weeds per pIOt e e e e e e e e e e e e e e

Effect of impeller speed on average number of
weeds per plot on 11th day after processing . .

Impact device for mechanically treating soil to
devitalize the entrained weed seeds . . . . . .

Effect of impact device soil treatments upon weed
counts in mineral soil 19 days after treatment.

Effect of impact device soil treatments upon weed
counts in muck soil 1h days after treatment . .

Redesigned impeller and impact plate. . . . . . e

Double exposure showing the floating action of
the soil pick-up rotor. Elevator removed . . .

Photograph of the complete centrifugal field
machine as used in 195u.e e e e e e e e e e e e

Schematic diagram of the 195h soil processing

machine e e e e e e e e e e e e e e e e e e e e

Number of broadleaf weeds 25 days after treat-‘
ment at planting time on.muck soil. . . . . . e

Emergence with various treatments on muck soil. e
Steps in mechanically processing soil . . . . . .
Comparison ofcheck row and treated row . . . . e

Soil structure dmnage immediately after '
processing. e e e e e e e e e e e e e e e e e e

Soil structure damage one year after processing .

Number of broadleaf weeds 22 days after treat-
ment of mineral soil at planting time . . . . .

Number of grass weeds 22 days after treatment
of mineral soil at planting time. . . . . . . .

Emergence of sugar beets with various treat-
ments on mineral soil at planting time. . . . .

39

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A9

A9

50

56
57
61
62

63
63

65

66

Table

II
III

IV

VI

VII

VIII

IX

XI

XII

XIII

XIV

XV

XVI

XVII

LIST OF TABLES

Emergence of sugar beets on mineral soil in 1953.

Page

26

Weed counts in 200 square inch plots on muck soil 32

Effect of pro-emergence herbicide treatments.
Sugar beets grown on muck soil. . . . . . . . .

Summary of Figs. 32 and 33 compared.with
Tables XVI and.XVII e e e e e e e e e e e e e e

1953 field test data. Mineral soil processed
With centrifugal machine. 0 e e e e e e e e e e

Analysis of variance of 1953 emergenCe of
sugar beets on mineral soil . . . . . . . . . .

Weed count and statistical analysis of greenhouse

tests using centrifugal machine on muck soil. .

Emergence per 100 inches. '195h field teats

0n.mu3k e e e e e e e e e e e e e e e e e e e e

Number of broadleaf weeds per square reot.
195).]. field teats on muCko o O o o o o o 0-. o 0

Number of broadleaf weeds per square'foot.'
l95h field tests on mineral soil. . . . . . . .

Statistical analysis of broadleaf weed ocunt
on mineral soil. 19Sh field tests. ... . . . .

Number of grass weeds per square feet.
19Sh tests on mineral soil. . . . . . . . . . .

Statistical analysis of weed counts of grass
weeds on mineral soil. 195h field tests. . . .

Sugar beet emergence per 300 inches.
195h field tests on mineral soil. . . . . . . .

Statistical analysis of sugar beet emergence.
195h field tests on mineral soil. . . . . . . .

Effect of pro-emergence herbicide treatments upon

all weeds in sugar beets grown on mineral soil.

Effect of pre-emergence herbicide treatments upon

weeds and sugar beets grown on mineral soil . .

58
61L
78
78
79
81
82
83
81L
85
86
87
88
89

89

INTRODUCTION
The Problem

The mechanization of a few of the farm crOps in the
United States can be considered as being complete. This
does not mean that there is a satisfactory solution to all
of the engineering problems concerning those crOps, but that
all of the hand labor has been eliminated in the production
of those crepe.

The same statement cannot be made about the production
of sugar beets, although much progress has been.made in the
mechanization of this crap in the past dozen years.

With this crep, the most progress has been made in
harvesting. Since 19h3 when harvesters were first introduced
into Michigan, the number of sugar beet harvesters has
Iincreased steadily so that in 1953 approximately 90 percent
of the acreage in.Michigan was machine harvested.

At present the greatest problem.in production is in
thinning the beets and in controlling the weeds in the row
during the first two months after planting. Johnson (18)
reports that in 19h6 this task required 32 man hours per
acre and was the largest single item in cost as well as
labor in the production of sugar beets in Michigan.

Considerable progress has been made since l9h6 in the
use of mechanical devices for thinning the beets and removing

 

 

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the weeds which are in the row. Some use has been made of
standard farm implements such as spike-tooth harrows, weed-
ers, rotary hoes and even row-crop cultivators. With the
exception of the rotary hoe, the implements are operated
across the rows of beets so as to remove some of the boots
as well as a percentage of the weeds in the row.

A more useful implement is the spring-tine thinner
developed by French (8) from the Dixie cotton chapper.
However, even this machine does not completely eliminate
the need for hand labor, but only reduces it by roughly ho
percent. Since mechanical thinners do not completely
eliminate hand labor their use has not become widespread
in Michigan. In 1953 only one acre out of 6% was mechani-
cally thinned and weeded. ‘

The April 1954 Sugar Beet Journal published at Saginaw,
Michigan by the Farmers and Manufacturers Beet Sugar Associ-
ation estimated that, there would be 95.000 acres of sugar
boots in Michigan in 19514.. Considering the rather limited
use of the thinner, it would appear. that there would be
somewhere between 2 and 3 million.man hours of labor expended
in 1951: on thinning and weeding sugar beets in Michigan.

Part of the problem is due to the unpredictable germi-
nation of sugar beet seed under field conditions. As a
result it is customary to plant approximately ten times as
many seeds as are actually desired and to thin while hoeing
to the desired stand. It does not appear that the problem

of erratic germination is primarily an engineering one. If
‘more information was available regarding the physical
requirements of germinating sugar beet seed, then it would'
be more logical for engineers to be working on the problem.
However, the problem of eliminating the weeds in the row
most certainly should occupy the attention of Agricultural
Engineers.

The Objective

This project has been directed the past three or four
years toward the study of possible methods of sterilizing a .
strip of soil in which the sugar beet seeds could be planted.
The sterilized soil would eliminate the need for any hoe
work except for thinning the boots. The need.probably is
not for complete sterilization, but for partial or temporary
sterilization of a strip approximately h to 6 inches wide.

The results obtained by Kinch (20) when using mechanical
energy to reduce the germination of seede mixed with the soil
were so encouraging that it was decided tocontinue the
investigation on the same train of thought. Some of the
results he obtained will be discussed in more detail later on.

This investigation is a continuation of the study of
mechanical energy as a means of reducing the vitality of
weed seeds in the soil. The investigation is a study of the
effects under field conditions of using a.machine which will
mechanically process a narrow strip of soil in the row for

weed control.

REVIEW OF LITERATURE

The object of this investigation was to study the _
possibilities of mechanically sterilizing a narrow strip of
soil in.which the sugar beets are planted so that some, or
perhaps all, of the hand labor of hoeing could.be eliminated.
Splinter (26) discussed the differential heating of various
parts of seeds with the idea in.mind of possibly being able
to kill the weed seeds by dielectric heating. Kinch (20)
discussed several other methods of applying energy to a
strip of soil to kill or to reduce the germination vitality
of the entrained weed seeds. Kinch listed the following
possible methods of applying energy to a strip of soil.

(a) High frequency electrical energy

(b) Heat energy by conduction

(c) Ultrasonic energy

(d) High current electrical energy

(e) Light energy

(f) ‘Mechanical energy

Kinch (20) studied three of these methods in detail,
(b), (c), and (f) and concluded that the last of these
methods had the best economic possibility; By mathematical
analysis and laboratory investigation he designed a device
which he called a ”semocidometer". This machine was unex-

pectedly similar to a centrifugal machine called an

"ENTOLATOR" (7) made by the Safety_Car Heating and.Lighting
Company Inc. of New Haven, Connecticut for the purpose of
killing insects and insect eggs in grain and flour.

The principle on which the two machines work is very
similar. The bulk material with the entrained pests, either
insects and their eggs or genuinating weeds and weed seeds,
is fed into the center of a high speed centrifugal fan which
accelerates the material toward an impact plate to injure
the pests. .

In the Patent Gazette, it was found that there are at
least seven patents issued to F. R. Smith, at _a__l_, (25) and
assigned to the Entolator Division. All of those patents
are concerned with devices for controlling insects and,
except for design details, all work on the same principle

as the one shown in Fig. 1.

There is one major difference in the design of this
machine and the machine designed by Kinch for control of
weeds and that is the use of so-called impactors in the
Entolator. From the description in the claims under patent
number 2,339,732 it appears that the object of the impactors
is to damage the insects while they are being accelerated
in addition to when they hit the outside impact plate.

Cotton (7) reports that when the machine was used at 1750 rpm
99.6 percent of the insects were killed, from which it
appears that the machine is quite efficient.

 

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Fig. 1. Schematic diagram of the ENTOLATOR machine made for
controlling insects in wheat and flour

This idea of using so-called impactors is somewhat
different from the design of the impeller in the machine
used by Kinch (20). In Kinch's machine a soil particle is
accelerated continuously from the center of the impeller to
its edge and receives only one impact when it hits the
impact plate. By studying the design of the impeller used
on the Kinch machine it is obvious that all soil particles
must reach about the same terminal velocity which is not
true of the 'Entclater”.

From information supplied by Kinch (20) regarding the
power required to Operate a small centrifugal machine, it

was estimated that a 20-inch diameter impeller running at
2600 rpm would require approximately 18 hp when processing
MOO pounds per minute of soil. This value checks quite
closely with that given by Huyett (16) who describes a
centrifugal shot peening machine used for work hardening
steel parts. This machine, when handling 300 pounds per
minute at a velocity of 3000 in. per second, requires 15 hp.

In attempting to arrive at an energy level, either
mechanical or otherwise, which will sterilize the weed seed,
it is necessary toconsider that there is.a great variation
in susceptibility to damage of weed seeds. Tools and Brown
(27) said that large weed seeds do not live more than a
year in the soil, but their final report on the Duvel Buried
Seed.ExPerhmant showed that of 107 species buried in 1902,
51 of them were still viable after 20 years. Thirty-six
species were still viable after being buried 39 Years.
Goss (9), in reporting on the same project, concluded that
depth had little effect and also that most weed seeds will
not perish when plowed under, or during a period of normal
rotation. From this it would appear thatno practical method
of sterilizing the soil in the field could expect to be 100
percent effective.

Heise (1h, 15), in a discussion of physical damage to
weed seeds, showed that by dehulling Green Foxtail seeds,
the germination was reduced from 87.5 percent to 15.5 percent

and when the tOp of the embryo was skinned the germination

was further reduced to 1.5 percent. In tests on Common
Ragweed seeds he says that "removal of the pericarp, pro-
vided the 'seed' is not damaged in the process, does not
result in excessive lowering of viability. But when the 'seed'
is even slightly damaged, viability is reduced close to zero."

Porter and.Koos (2h) concluded about the same thing in
reporting that ”hulled fruits of Sour Dock, Black Bindweed,
Small Ragweed, naked fruits of Green and'Yellow Foxtail
found in commercial seed samples showed little or no ability
to produce plants”.

Bass (2) confirms the results of other investigators
in concluding that badly injured weed seeds have their
vitality much reduced below that of uninjured seeds.

Koehler (21) has for several years been studying the
effects of mechanical damage to seed corn. He says that
'severe crown injury or an injury over the plumule resulted
in less than 10 percent germination“. Borthwick (3) and
also Barter (l3) attempted to classify the type of growth
which resulted from physical damage to Lima Beans which are
easily damaged. Borthwick (3) and Barter (13) did.not give
any values of‘mechanical energy or force necessary to cause
certain types of physical damage. _

The most complete study found of physical damage to
seed, was by Bainer and Borthwick (1) who also made their
study on seed beans of the lime type. They found when
threshing baby lima beans at 9.1 percent moisture that the

 

 

 

mechanical damage increased from 7.6 percent to 52.5 percent
as the cylinder speed of the threShing machine was increased
from 770 fpm to 1560 fpm. In order to show that the velocity
of impact was the cause of the damage they drapped the beans
from various heights to give a velocity equivalent to the
cylinder speed. The results are shown graphically in Fig. 2.

If information similar to that shown in Fig. 2 was
available for all weed seeds then there would not be as
large a problem in attempting to design a centrifugal
machine or some other type of mechanical device to sterilize
the soil. , H b

The data by Bainer (1) shows clearly the energy level
necessary to reduce germination almost to zero if the seed
is dry. Unfortunately most weed seeds, except for those on
the surface during a dry part of the season, have a rela-
tively high.moisture content and therefore are not as sus-
ceptible to physical damage as is indicated by the chart.
Also the size of the seed.must certainly be a variable which
must be considered.

A recent unpublished paper by Bunnelle (h) presents
information similar to that by Bainer (1) except that the
seed being studied was alfalfa seed. Fig. 3 is a photo-.
graphic copy of one of the charts presented in.his paper.
The moisture content of the seed is not specified, but it
is assumed that it was dry enough to store and conceivably

about 1h.percent.

 

 

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Fig. 3. Effect of combine cylinder speed upon the germi-
nation of alfalfa seed '
From unpublished paper by Bunnelle (h)..

It is, of course, risky to generalize or draw conclup
sions from.Figs. 2 and 3 in regard to impact dmnage to any
seed. However, it is logical to assume that the smaller
seeds would require a greater impact velocity to give the
same germination reduction and this appears to be true as
far as Figs. 2 and 3 are concerned.

For purposes of comparison assume that the moisture
content of both the alfalfa seed and the lima beans is at
lh.l percent. .Assmme that the genuination reduction of both
is 20 percent. Then from Fig. 2 it may be seen that the
impact velocity is roughly 1500 fpm for the lima beans and
roughly 6000 fpm.for the alfalfa seed. Under these conditions

12

the kinetic energy required to reduce the germination to 80
percent is 16 times greater for the alfalfa seed than it is
for the lima beans.

It would be very desirable to have similar information
about several sizes of weed seeds, but this information is
not available, or at least was not found.

The above comparison was made on the basis of a 20
percent reduction in the germination of the two types of
seeds. However, for weed control a 20 percent reduction in
the weed.p0pulation would not be very useful.

How won the above type of information would apply to
weed seeds is not known. Most weed seeds are inherently
hard seeded; that is, they will not necessarily germinate
when subjected to the correct moisture and temperature con-
ditions. They usually become dormant shortly after’maturing
and.may stay that way for several years, as was shown by
the Duvel (9) buried seed experiment.

From.the standpoint of designing a field machine to
process the soil for the purpose of reducing the germination
of the weed seeds it is essential that some positive infor-
mation be obtained. Several questions have been prompted
by this literature search. 7

1. ‘What critical impact velocity will cause a specified
reduction in the germination of various weed seeds?.

2. 'What is the effect of the moisture content of the
weed seeds on the critical impact velocity?

 

 

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3. 'What is the moisture content of the weed seeds in
the soil?

h. “What is the effect on the critical impact velocity
of mixing the weed seeds with soil?

5. How much soil would it be necessary to process in
order to obtain reasonable weed control?

Of all these questions the last one is the easiest
one to answer. Chepil (6) reports that by far the highest
emergence of weed seedlings of the species studied was from
the seeds lying on the surface of the ground. However, he
does not give any percentage or exact depths from which the
weed seedlings grew. He stated that from 60 to 99 percent
of the weeds emerged before June 30.

Kinch (20) made a study of the depth from which weed
seeds sprouted on disturbed soil. From his data the dis-
tribution chart ioni . h.was plotted. It is interesting
to note that 96.3 percent of all the weed seeds which
germinated were in the tap three-fourths of an inch. From
this information it is apparent that it would not be necessary
to process more than three-fourths of an inch of soil or
perhaps one inch at the very most.

‘When using the semocidometer at #000 rpm Kinch reports
that when processing a one-inch layer of soil only h.8
percent as many weeds grew in the first 12 days in the
processed layer as did in the unprocessed plot. His work

was done with disturbed mineral soil and then exposed to

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15

fluorescent light indoors. With.the equipment which he
used the total velocity of thesoil particles leaving the
impeller was approximately lu,900 fpm.

In any complete study of the problems involved in
sterilizing the soil some consideration must be given to
the resulting changes in the soil preperties. It is quite
likely that any treatment to the soil, either mechanical or
otherwise, would result in some damage to the soil structure.
In most soils the crOp yields are reduced when the soil is
worked.more than the minimum necessary in order to prepare
the seedbed and tocontrol the weeds. Keen (19) and.many
other soil physicists have said in effect that any implement
or practice which tends to work the soil excessively causes
the tilth to become less favorable to plant growth. How-
ever, because of time limitations this related problem of
soil structure damage was only studied superficially.

Newhall (22), a plant pathologist, in a discussion of
the theory and practice of soil sterilization says that
complete sterilization is undesirable and that instead one
should “partially sterilize” the soil. He was undoubtedly
thinking of microorganisms as well as weeds and weed seeds.
It is quite unlikely that any mechanical sterilization
process, such as this project is concerned with, could ever
achieve complete sterilization even if it was desired to do

80.

INVESTIGATION

Part I
Design of the Centrifugal Soil Processing Machine

Functional requirements p

The design of a machine to process soil was actually
a secondary object in this investigation. The primary
object of the study was to determine the effects of mechani-
cal energy upon the germination and growth of weeds which
have been subjected to various treatments. However, before
any studies could be made some equipment had to be designed
and constructed which would subject the soil to the desired
treatment. ,

It must be kept in mind that a functionally adequate
machine was necessary, but that no attempt was made to
design a.machine with mush of a service life.

An experimental two-row sugar beet planter that had
been used.by Carleton gt a; (5) was available to be used on
this research project. It was decided to mount the processing
equipment on the planter in such a way as to have one row
of the planter as a check row and the other row as a treated
row. .

From the review of literature and from the equipment

available the following criteria were established:

17

l. The strip of soil to be processed should be approx-
imately 0.75 inch deep by'h to 6 inches wide.

2. The ground speed was established by the tractor
available which had a low gear ground speed of 2.8 mph at
1500 rpm engine speed.

3. The experimental planter'which was to be used as
a basis for the machine was designed for the threeepoint
hitch of a Ford type tractor. The height of the planter
could be regulated by the hydraulic lift of the tractor and
by an adjustable tail wheel. The row spacing was fixed at
26 inches.

h. It was estimated that an impeller 20 inches in
diameter and with vanes two inches high would have sufficient

capacity to handle the soil that would need to be processed.

Impeller design _ v

Kinch (20) deve10ped an equation (see Appendix) for
the velocity of a soil particle being accelerated by an
impeller of this type. The impeller shown in Fig. 5 was
first designed with no more than a rough idea of what its
speed should be in order to give the same particle velocity
as the Kinch machine. If we assume that the impeller of
the Kinch.machine is turning at too rpm and.that the
coefficient of friction of soil on steel is O.h.then it can
be shown that the total velocity of a soil particle leaving
the impeller is approximately lh,900 fpm.

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19

For the conditions of the larger 20 inch impeller the
equation.of motion of a soil particle has been worked out
and is shown in the Appendix. Since the coefficient of
friction of soil on steel very definitely affects the radial
velocity some attention was given to determining that effect.
Values for the coefficient of friction of various soils on
steel are given by Nicholgzgor several mineral soils, but no
information was found for muck soils. By using the values

given by Nichols the curve shown in Fig. 6 was calculated
for the 20 inch impeller shown in.Fig. 5 turning at 2600 rpm.

Eggplete machine

The design details of the field.machine, with the
exception of the impeller, are unimportant as far as this
study is concerned. .A few comments about the design of the
machine will suffice. _

A schematic diagram of the machine viewed from the left
side is shown in Fig. 7. A photograph of the same machine
viewed from the right side is shown in Fig. 8.

Power was transmitted from the tractor by the power
take-off and from there to the impeller by means of roller
chains, sprockets and.shafting. The impeller itself was
mounted on the pulley end of a Ford belt pulley attachment.
This made an excellent dust tight bevel gear box in addition
to having the necessary bolt holes for mounting the gear box

on the frame of the planter.

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Fig. 8. Photograph of the 1953 soil processing machine

The soil pick-up rotor cannot be seen clearly in Fig. 8
because of the soil elevator. The pick-up rotor actually
throws the soil sideways into the elevator and not backwards
as might be assumed from the schematic diagram in Fig. 7.
The rotor turns at 500 rpm.

Fig. 9 shows the planter in the raised position with
the processed row directly beneath it. The sheet metal
shield in Fig. 9 was added to the impeller housing to collect
the soil being blown out by the air.. The steps in the pro-
cessing of the soil can be seen here. At (a) the soil has
been lifted into an elevator leaving a shallow furrow. it
(b) the processed soil has been deposited in a band approxi-
mately four inches wide and at (c) the sugar beet seed has

23

 

 

Fig. 9. Close-up view of the right-hand side of the

planter lifted up to show the processed strip

of soil
been planted in the processed soil which will then be packed
down by the press wheel behind it.

Fig. 10 is a rear view of the rock screen which is
necessary to remove the larger rocks when processing mineral
soil. It was made with a wire screen having a one-inch by
two-inch mesh. in eccentric with a one-half inch stroke
shakes it at 5&0 cycles per minute.

 

 

.,'

 

 

Fig. 10. Rear view of soil processing machine showing
rock screen

25

Part II
Field Tests in 1953

Mineral soil tests
The planter with the soil processing attachment was
used to plant four replications of the following treatments
in.the Agricultural Engineering field at the corner of
Harrison Road and Forest Road.
0 - no process (on left side of planter only)
8 K - impeller speed 1600 rpm, no Krilium

l O

lel - impeller speed 1600 rpm, 0.1% Krilium 9 by
weight of soil processed

SéKo - impeller speed 2600 rpm, no Krilium

sle - impellor speed 2600 rpm, 0.1% Krilium 9 by
weight of soil processed

Each row was 80 feet long and the row spacing was 26
inches. The soil conditioner (Krilium 9) was fed by hand
into the rock screen so that it was mixed thoroughly with
the processed soil. In all the treatments, with the exception
of the check, the depth of the processed soil was roughly
one inch. These plots were planted on July third and
fourth and were preceded by a rain of about one-third of
an inch. A half-inch rain fell on the fifth of July so
that some crusting occurred. It was expected that the pro-
cessed soil would crust more than the unprocessed soil so
it was for that reason that the soil conditioner was added.

Due to late planting and the dry weather following the
planting and processing of the mineral soil plots, very few

weeds grew.

 

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26

Table V in the Appendix shows the results of the weed
count on the mineral soil plots, but it is obvious without
any statistical analysis that the information is meaningless.
There are not enough weeds in either the processed or the
check plots to be a problem.

It was expected that the processed soil would tend to
crust more than the check plots so it was decided to evaluate
this problem by counting the emergence of sugar beets.

In Table I the emergence data of all of treatment SIKO
is missing because of faulty planting mechanimm.

The analysis of variance is shown in Table VI in the

Appendix.

TABLE I

EMERGENCE OF SUGAR BEETS ON MINERAL SOIL IN 1953
(Plantslper 100 inches)
=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaEaEaaaaa====================s

 

 

 

'Treatment
Replication _ ,.i_ _

l 102 21 u? 62 66 35
2 105 100 76 hl 10h 66
3 1141 113 69 88 121* 92*
1+ 110* 72* 35 62 9b, 76

Average 116 76 57 63 96 72

Corrected ‘

average** 116 8h 57 70 96 80

 

*Missing data filled in by method outlined by Goulden (10).

Averages cerrected because right hand planter (processed
row) planted 10 percent more sugar beet seed than the left
hand planter. .

27

The F test shows the treatments to be highly signifi-
cant which.means that the averages of one or more of the
treatments is significantly different than the others.
Because of the missing data it was necessary to correct for
the treatment sum of squares and when this is done the
adjusted.mean square for treatments is found to be 1960 which
is still highly significant. By means of the "t" test where
the standard deviation is corrected for missing data it can
be shown that by using Krilium during the processing of the
soil the emergence rate of the sugar beets is significantly
higher than any of the check plots and that 82Kl is signifi-
cantly better at the 99 percent confidence level than SZKO'
There is not a significant difference between any of the
check plots and the processed plots without Krilium (SéKo),
although it should be noted that the processed plot SZKO
did have a lower emergence rate than the average of the
check plots which is as expected.

It was surprising that the use of Krilium increased
the emergence rate over_the check plots. Figs. 11, 12 and 13
illustrate the appearance of the check row, and the processed
row without Krilium and with Krilium.

The row is locatedat the three inch mark on the
measuring tape. These photographs were taken three days
after the sugar beet seeds were planted so the seedlings

do not as yet show.

 

 

t‘e

luvkl

28

 

 

Fig. 11. Crusting of Brookston clay loam on check row
three days after planting
A half-inch rain fell two days after planting.

 

#:xnmnammuemmxmmuauuhfi

 

 

Fig. 12. Crusting of Brookston clay loam on row processed
at 2600 rpm and approximately one inch deep

29

 

 

Fig. 13. Crusting of Brookstcn clay loam processed at
1600 rpm and treated with 0.1 percent Krilium

Muck soil tests

 

It has been estimated that approximately ten percent
of the sugar beets in Michigan are grown on much soils. For
the following reasons it would appear that the potential use
of this machine would be greater on muck soils than on
mineral soils.

1. In general, the weed problem is greater on muck
soils than it is in mineral soils.

2. The bulk density of muck soil is roughly only one-
half that of mineral soils. Assuming that the volume of
soil is the same in both bases, then the power requirement
to run_the impeller would be approximately one-half.

3. Since muck soil has no structure then there would

30

not bevany damage to the soil from that standpoint.

1&0 Since there are no rocks in muck soil, the design
of the machines could be simplified.

The machine was used on muck soilto plant eight rows
of sugar beets that were 200 feet long. Four of the rows
were check rows, two rows were processed at 1600 rpm and
two rows were processed at 2600 rpm. These planting were
made on July 20. ‘

Because the soil was quite dry when the above plantings
were made and because it was difficult to control the depth
of the processed soil it was decided to process some small
plots of 200 square inches.from which the soil was sc00ped
up manually, processed and laid back down manually. No
sugar beet seed was planted with these'plots. The following
treatments were replicated three times.

SOD1 - no process, soil disturbed 3/11. inch deep

SODZ - novprocess, soil distrubed 1% inches deep

31Dl - impellor 1600 rpm, soil processed 3/11 inch deep

81D2 - impellor 1600 rpm, soil processed 1% inches deep

:3le ".' impellor 2600 rpm, soil processed 3/)... inch deep

32D2 - impellor 2600 rpm, soil processed 1% inches deep

These manually lifted and replaced plots were on the
same muck soil as was used for machine planting. All of the
muck plots were located on Dr. Buford Grigsby's weed control

field on Abbott road. These small plots were processed on

31

July 23 and since the soil was quite dry at the time 1.2
inches of water was applied to the plots on July 27. On
August 2 approximately 2 inches of rain fell so that there
was an ideal growing condition for the weeds. The muck
plots which were planted and processed with the machine
on July 20 did not receive any rain or irrigation water
until it rained 13 days later.

The dry weather following the machine planting and soil
processing on the muck soil plus the difficulty experienced
in regulating the depth of the processed soil resulted in
very erratic sugar beet emergence and weed growth. The
observation showed that there was no measurable difference
in any of the treatments, or between the treatments and the
check rows.

The manually lifted and replaced small plots (200 square
inches) also gave disappointing results, but were not com-
pletely worthless. These plots were replicated three times,
but one of the replications was ruined by a.mo1e and a
second replication was badly flooded and covered with trash
so all of the resulting information is from one replication
only.

The small plots shown in Fig. 1h.were treated on July
23 and the weed counts (Table II) were made on August 10
which was 18 days later.

Since there were no replications of the above tests

there is no way in which an analysis of variance could be

 

H“

I'LlEI..I

. 11nd

32

 

Fig. 1h. Weed growth on muck soil showing effect of six
different treatments
Photograph taken 1h days after treatment.

TABLE II
WEED COUNTS IN ZOO-SQUARE INCH PLOTS ON MUCK SOIL

 

 

 

 

Treatment
I’130 D2530 D131 D231 D132 D232
Grass 1&9 108 88 162 116 69
Broadleaf weeds 325 223 217 282 125 33?
T0931 h7h 331 305 huh Zhl #06
Total each
speed a 805 7H9 6H7

 

a /_

 

33

made. It is apparent that the weed count does go down as

the speed of the impeller has been increased. The wood.
pepulation has decreased approximately 20 percent where the
impeller speed is 2600 rpm (82) as compared to the check plot
(3,).

Discussion of 1953 field tests

. s..- -h'”
' a

l. The results of the tests on mineral soil were
negative as far as the weed control is concerned. This may “
be due partly to the dry weather, the lateness of the season I
and the poor depth control of the processed soil.

2. The results of the emergence data on the mineral
soils were surprising. The data showed that by using Krilium
in combination with this machine the sugar beet emergence
was increased significantly over the check row or the pro-
cessed row which was not treated with.Krilium.

3. There were no observable differences on muck soil

where the planter with the soil processing attachment was
used as a field machine. The weed growth was adequate for
the tests, but there was no difference in the treatments.
Again difficulty was experienced in maintaining the proper
depth of processed soil. Also considerable contamination
of the processed soil was observed, coming from the furrow
cpener. This latter problem existed when the machine was
used on both mineral and muck soil.

h. The processed.muck soil, when it was acceped up and

replaced.manually, had fewer weeds than the unprocessed soil,

but the difference was not large.

3h

Part III

Greenhouse Studies

Centrifugal machine tests on muck soil
In order to eliminate as many of the field variables
as possible it was decided to hand feed.muck soil with the
entrained weed seeds into the centrifugal field machine and in
then catch the processed soil in a bucket. The processed
soil would then be spread out in frames in the greenhouse vi.
and kept moist, to germinate the weed seeds. I
The equipment used in connection with the greenhouse
tests using the centrifugal field machine was essentially
the same as was used in the field tests during the summer
of 1953. However, some slight changes were made in the
design of the impeller. These are shown in Fig. 15.
When the cover was taken off of the impeller housing
of the field machine after being used during the summer of
1953. it was observed that some soil tended to stick to the
impact plate above the region in line with the impeller.
Thus, it would seem that some of the soil was not being held
in contact with the blades of the impeller until reaching
the outside edge, but instead slipped off the blades.
To improve upon this apparent difficulty the impeller
was redesigned as follows:
1. A short piece of angle iron was welded to the tOp
edge of each blade to form a trough to guide the soil while

 

 

 

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36

it was being accelerated._

2. The center post of the impeller was lowered.

3. The inner ends of each blade were lowered. This in
addition to lowering the center post allowed the soil to drOp
further into the center of the impeller before being accel-
erated outward.

Procedure. Muck soil was brought into the greenhouse

 

from.a field which had a high pepulation of weeds and was.
allowed to soak for a period of 11 days before processing.
The treatments applied were as follows:

Code Depth in inches Impeller rpm

21:1 % luoo
9132 1 1870
0133 i 2600
”131. it 3&70
D231 1 lhOO
D282 1 1870
n253 1 2600
Dzsu 1 3470
0331 2 luoo
D382 2 1870
D383 2 2600
D33“. 2 314.70

Each of the treatments was replicated three times and
within each of the replications the treatments were random-
ized.

Each plot consisted of a rectangular frame Open at the

tap and bottom, u.inches wide by 25 inches long so that each

 

37

contained 100 square inches. Three days after the treatments
were applied all of the plots were watered lightly to keep
the surface from drying out before the weed seeds had a
chance to sprout.

In order to get the correct depth of processed soil,
each plot was partly filled with unprocessed soil and then_
filled to the top with the correct depth of processed soil.
Thus, the depth of processed soil was controlled quite
closely, and since the soil was placed in the plots manually,
there was very little chance of it being mixed with any soil
from another treatment. This last item was one of the most
difficult variables to control in the field and.made com.
parison of treatments difficult.

Results. Weed counts were made eleven days after the
treatments were applied. Grass and broadleaf weeds were
counted separately in order to determine whether or not
there might be any differential killing effect by the cen-
trifugal machine. The complete data for this test are
shown in.Appendix Table VII.

Fig. 16 is a photograph of the second replication taken
12 days after the treatments were applied. It isspparent
that there are some differences in the treatments.

A scatter diagram is shown in Fig. 17 comparing the.
number of grass and broadleaf weeds in the various plots.

It was thought that this ratio might change as the speed of

38

 

 

Fig. 16. Photograph of weed growth 12 days after treatments
were applied
Greenhouse tests with centrifugal machine on muck
soil.
the impeller was increased, but this is apparently not true.
In other words, there was not any differential effect so far
as treatment was concerned and the ratio remains constant.
The curve in Fig. 17 was sketched in by eye.
A statistical analysis of this data was made and is
shown in Appendix Table VII. It should be noted that impeller
speed is highly significant, but that the depth of processing
appears to have no effect. If the depth of processing had
been much less then it might have had an effect.
Even though the speed of the impeller was highly signifi-
cant, the results were not those desired.' Fig. 18 shows the

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count at lhOO and 1870 rpm, but at the higher speeds this

trend was reversed.

Impact device tests L4

One of the problems involved in using the centrifugal

a- . . ‘r -..u.

machine is that there is no convenient way to actually : 4

“l "

measure the power absorbed by the soil. As a result the
soil particle velocity and the energy per unit weight of
soil could not be determined except by approximation. The
soil particle velocity could be calculated rather closely
if the coefficient of friction for the soil in question was
known, but for muck soil this information was not available.

A more basic way of approaching this problem of mechan-
ically sterilizing the soil was to use an impact device by
which a predetermined amount of energy could be applied to
a known.weight of soil. The impact device shown in Fig. 19
.was constructed for this purpose.

The impact device consists of a weight of 82.2 pounds
which can be lifted to a height of eight feet. It is guided
by 2 one-inch pipes which are welded to a steel plate which
in turn is bolted to the floor. The weight is lifted to the
desired height by a fork lift truck which can be seen in the
background in Fig. 19.

 

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Fig. 19. Impact device for mechanically treating soil to
devitalize the entrained weed seeds

The die to hold the soil_during the impact is 10 inches
long by 2.32 inches wide by 0.5 inch deep. When full the die
holds about llu grams of muck soil or about 215 grams of
mineral soil.

The following treatments were applied to both mineral
and muck soil, and replicated three times in both cases.

 

Code Depth of soil in inches Drop height in inches
d 0 one}; ' h 5
1 e
dig; 1/8 9.0
d1h3 1/8 18.0
011: 1/8 36.0
0112'; 1/8 68.0
d h 1 2 .5
can: 172 15.0
<12 1/2 18 .0
dzbfi 1/2 36.0
can; 1/2 68 .0

#3

Thehtreatment 9f the 1/8 inch depth of soil consisted
of four pooled samples so that the amount of soil for the
1/8 inch treatment and the 1/2 inch treatment were the same.
The hammer which in Fig. 19 is standing on end beside
the die was made to fit inside the die with about l/6h inch
clearance. . 1
Both the muck soil and.mineral soil used in this ‘
experiment were taken from fields badly infested with weeds.
The moisture content of the muck soil was approximately 150 a
percent and the mineral soil was approximately 15 percent.
The treated soil samples were each placed in a lZ-ounce
cottage cheese carton and pressed with a weight which
applied a pressure of approximately three psi. The Open
cartons were placed in a greenhouse and the soil was watered
daily so that the surface remained moist.
The results of these two tests are shown graphically
in Figs. 20 and 21. Because of the small size of each treat-.

ment the total number of weeds in each carton was quite small.

Discussion ofggreenhouse tests

There appeared to be no selective effect upon the grass
weeds and the broadleaf weeds when using the centrifugal
machine at various speeds. This is indicated by the straight
line relationship between the grass and.broadleaf weeds as
the number of each increased.

‘When using the centrifugal soil processing machine to

treat muck soil in the greenhouse the effect was to decrease

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1&5

the total number of weeds when the impeller was running at
slow speeds, while at high speeds the number of weeds was
significantly increased. There are two possible explanations
for this result.

1. The data may be from a sampling freak, but this
possibility is rather remote since the "F" test shows that
the effect of impeller speed is highly significant.

2. An explanation which seems much more reasonable is
that there may be considerable scarifying of the hard-seeded
weed seeds at the higher Speeds, while at the low speeds
the germinating weed seeds are killed. It should be remem-
bered that muck soil was used for this test. It is reason-
able to assume that the abrasive action of mineral soil
would cause much more damage to the weed seeds than.muck
soil, and therefore, the expected results may be consider-
ably different.

It was quite disappointing to find that there was no
effect on the weeds when using the impact device. The range
in the amount of energy being imparted to the soil was much
'greater‘with the impact device than it was with the centrifu-
gal machine. Using the impact device, the energy ranged
from approximately 60 footLpounds per pound of soil to
7000 foot-pounds per pound of soil. The energy imparted to
the soil in the centrifugal machine was about 1100 foot-
pounds per pounds of soil when the impeller turned at
2600 rpm.

 

 

 

 

A6

Compared to the diameter of a weed seed, the thickness
of soil in the impact device was quite thick. This may
have protected the weed seeds during the impact by supporting
the weed seeds on all sides. In the centrifugal machine
the layer of soil striking the impact plate was much thinner
and therefore the weed seeds received.much less protection.
Also in the centrifugal machine there was a shearing and
abrasive effect because the seeds would hit the impact

plate at an angle of roughly no degrees from the tangent.

#7

Part IV
Field Tests in l95h

Changes in the centrifugal field machine

After using the centrifugal field machine in 1953 it
was obvious that its functional design could be improved.

‘When using it on mineral soil there was a tendency for
soil to build up on the impact plate so that the impeller
actually rubbed on the deposit of soil. This was improved
by placing the impact plate at a 30 degree angle from.the
vertical. Reference to Figs. 22 and 25 will show how this
was accomplished. 'With the impact plate at an angle, the
soil particles are directed downward when they hit thereby
keeping the impact plate clear. According to Kinch (20)
this soil deposit on the impact plate had no effect on the
damage to the seeds which hestudied. However, in the 1953
field machine it did build up so much that it had a serious
clogging effect. The change in the impact plate made it
similar to the design of the impact plate of the ENTOLATOR
shown in Fig. 1.

Another difficulty experienced was in maintaining a
constant depth with the soil pick-up rotor. It was mentioned
in the review of literature that it was desired to process
a strip of soil approximately three-fourths of an inch deep,
but because the soil pick-up rotor was attached rigidly to
the frame of the planter in 1953 it did not closely follow

 

Fig. 22. Redesigned impeller and impact plate

the contour of the soil. Reference to the schematic
diagram in Fig. 25 and the photograph in Fig. 23 shows how
this difficulty was overcome. The soil pick-up rotor and
suspension were redesigned so that the soil pick-up rotor
would float with respect to the soil surface by use of a
parallel linkage and an adjustable depth gage wheel.

In the 1953 field tests Krilium was added to the pro-
cessed soil by manually shaking it onto the rock screen as
the machine was traveling across the field. The accuracy of
this method was questionable. A knapsack sprayer was added
in 195k to spray the soil conditioner and herbicides onto

the rock screen before the soil had been mechanically processed.

#9

   

Fig. 23. Double exposure showing the floatfhg action of
the soil pick-up rotor
Elevator removed.

 

Fig. 2h. Photograph of the complete centrifugal field
machine as used in 195h

 

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51

To avoid any possibility that emergence Of the sugar
beet seedlings might be affected by a lack of fertilizer
two fertilizer boxes were added to place the chemical
fertilizer with the seed at a depth of one and one-fourth
inches below the surface. They were calibrated and adjusted
to apply approximately 200 pounds of h-l6-16 fertilizer per
acre. f

In the 1953 field tests the processed soil was replaced
in front of the furrow opener. After the 1953 tests it was
thought that replacing the soil in front of the furrow
Opener might have resulted in some contamination of the
processed soil because of some unprocessed soil having been
picked.up by the furrow Openers from below the processed
soil and then drOpped on tOp of the processed soil. The
easiest way to correct this was to add an auger to move the
processed soil from the impeller housing to the rear of the
furrow Opener to be followed by the press wheel. Obviously
a better way to have accomplished this would.have been to
locate the soil processing impeller housing behind the
planter furrow Opener, but to do sO after the machine had
been constructed would have required.much work and time. The
use Of the auger appeared to be functionally satisfactory,
and therefore was added.

During the 1953 field tests a tractor was used which
traveled approximately 2.8 mph in low gear at an engine
speed of 1500 rpm. It was Obvious when using it that it did

52

not have sufficient power to always maintain correct engine
speed when processing a strip Of soil three-fourths of an
inch deep by five inches wide.

By referring to Appendix I it can be seen that the soil
particle velocity is approximately 275 fps when the impeller
runs at 2600 rpm. Under the above conditions approximately
7.h pounds of soil per second would be processed. It can be
shown that the theoretical power under these conditions
would be 15.8 hp to run the impeller. Since some power was
needed to run other parts of the machine and to prOpel the
tractor, it is conceivable that the requirements might exceed
the power available from a Ford tractor.

. For the 195% field tests it was decided to use a
different Ford tractor which had a special transmission
which allowed the tractor tO travel at 0.9 mph in low gear
at 1500 rpm engine speed. At this speed the power needed
was approximately one-third of what was required in the
1953 field tests. .

These changes just described are shown in Figs. 2M and 25.

Variables in the 1954lfield tests

From an examination of the 1953 field tests and the
greenhouse tests which followed, it appeared that the mechan-
ical treatments alone have very little or no beneficial
effect for controlling weeds.

It was therefore decided to devote the 195h field work

53

to a study of mechanical treatments in combination with
chemical treatments.

It was thought that this machine offered an excellent
means for mixing a soil conditioner with a narrow strip Of
soil. In the 1953 field tests this appeared to give a
promising increase in the emergence Of sugar beets, there-
fore it was decided to enlarge upon these tests.

It had been suggested that there was a possibility that
some herbicides might be more effective if thoroughly mixed
with a layer of soil instead of being sprayed on the soil
surface as is the usual custom. The hypothesis is that
there would be more area Of the weed in contact with the
herbicide and therefore there would be a better chance Of
killing it. In addition it was thought that the mechanical
action upon the weed seeds would tend to make them more
susceptible to injury by the herbicide.

In summary the variables in the l95h field tests were
as follows:

1. Two soils (Brookston clay loam and muck)

2. Five herbicides (CMU, CIPC, TCA, Dalapon, Endothal)

3. Three herbicide rates

h. Two impeller speeds (1730 and 2600 rpm)

5. Three Krilium rates (18, 36, and 72 pounds per acre)

(for crust control, Monsanto recommends 18 pounds
per acre)

6. Two crOps (sugar beets and onions)

The herbicide rates were determined by using the rate

5h

suggested by the manufacturer plus one rate greater and one

less.

Muck soil field tests

It was decided to again include tests on.muck soil
because there is a greater weed problem on muck soils than
on mineral soils and also because muck soil is more adaptable
to mechanical treatments than mineral soil.

The procedure in these tests was as follows: The depth
gage wheel in front of the soil pick-up rotor was adjusted
to pick up a strip Of soil three-fourths Of an inch deep.
This strip was approximately five inches wide and in the
shape Of a segment Of a cylinder.

The furrow Openers were adjusted so as to plant the
seed approximately 1.25 inches below the surface for both
the treated and the untreated row. Since the machine was
originally constructed as a two-row planter with only one
row being treated there were as many check rows as there
were treated rows. The row spacing was fixed at 26 inches.

The planter was adjusted to plant approximately 96
sugar beet seed segments per 100 inches in both treated and
untreated rows. The sugar beet seed used was US MOO.

The same planter box seed plates were used for onion
seed, and since the seed was smaller and the adjustment was
not changed there were approximately 200 onion seeds planted

per 100 inches.

55

To pull the planter a Ford tractor was used which had
a 3 to 1 underdrive so that in low gear with the engine
running at 1500 rpm the ground speed Of the tractor was
approximately 0.9 mph.

Each treatment consisted Of one BOO-foot row from which
four samples were taken.

The moisture content Of the soil was not ideal for these
tests or for the growth Of sugar beets and weeds. Only 0.3
inch of rain fell from June 1 to June 29. The sugar beet
seed was planted on June 1h, 15 and 17. .

The results of these tests are shown graphically in
Figs. 26 and 27. The original data is in the Appendix. A
more complete description Of the herbicides used is in the
Glossary.

It was assumed that the weed seed pOpulation and the
soil were uniform, and.that it would not be necessary to
randomize each treatment within each block. However, it
was Obvious when looking at the plots three weeks after the
treatments had been applied, that there was considerable
variation in the weed pOpulation in the field. It was
observed that there was more variation due to location in
the field than to treatments so that Fig. 26 is not a true
representation of the effects Of the treatments. In other
words, the treatments also include an effect due to location
in the field which in this case is impossible to separate

from the treatments.

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58‘

The check plots used for comparison were not selected
at randmm. The entire area that had been planted to sugar
beets and onions was divided into two areas which by obser-
vation apparently had different weed pepulations. From the
center of each of these two areas a check plot was selected
to be used in comparing other treatments in that area.

For comparison Table III is included. The data are from
an unpublished report by Grigsby (11) and is. the only .
information which could be found to compare with Fig. 26.

_ TABLE III
EFFECT OF PRE-EMERGENCE HERBICIDE TREATMENTS”

(Sugar beets grown on.muck soil)

 

 

 

Treatment ‘Weeds per square foot Percent
Broadleaf Grass Total °f total
TCA - 10 lbs/A 37» 2.6 39.6 75
TCA - 20 lbs/l lu.6 o_ 1a.6 28
Check h6.h 6.3 52.7 100

 

*Data from unpublished report by Grigsby (11).

By comparing Fig. 26 and Table III it is apparent that
the percentage reduction in weeds by using mechanical treat-
ment plus TCA is no greater than TCA alone.

‘When using CMU, for example, with the mechanical treat-
ment the weed counts were actually greater than the check
plots in five out of the six treatments. Since it was not
possible to calculate the LSD it is not possible to state

59

whether or not any one treatment is significantly different
from.another. However, since most of the treatments have
roughly about the same weed counts as the check, it would
appear that the combination of mechanical treatments plus
the herbicides is no better than the herbicides alone.
Therefore it would seem that the combination of mechanical
plus herbicide is less effective than the herbicide by
itself. A possible explanation for this apparent phenomenon
is that the organic matter in soil “ties up"cr neutralizes
the herbicides before they have an Opportunity to affect
the weeds.

This possible neutralizing effect seems to also be an
eXplanation for the small reduction in the emergence of
sugar'beets even at the rate of two pounds per acre of CMU
which on.mineral soil appliedto the surface of the soil
is usually fatal to sugar beets (see Fig. 3h).

The emergenceof the sugar beets and the onions shown
in Fig. 27 is of no particular value in this test since the
weed control was not an improvement over that which could .
have been obtained by surface application of the herbicide.
However, had there been a significant improvement in the
-weed control by any of the herbicides then it would have been
useful information in determining the tolerance limit of
the sugar‘beets to that particular herbicide in combination
with the mechanical treatment.

60

Mineral soil field tests

The procedure in the mineral soil field tests was much
the same as it was in muck soil with the following exceptions.
There were no tests made on onions on mineral soil and
therefore the chemical CIPC was not used. Two impeller
speeds were used whereas on.muck soil only one was used.
On the muck soil it was impossible to use the fertilizer
boxes because there was not enough traction for the drive
wheel to turn both the fertilizer boxes and the planter ‘
boxes. Therefore the fertilizer boxes were disconnected.
However, on the mineral soil the traction was adequate so
fertilizer was applied at the same time at the rate of 200
pounds of n.1e-1e per acre in the same furrow with the seed.
In Part II? it was mentioned that in the 1953 field tests
the use of Krilium resulted in a considerable increase in
the emergence of the sugar beets. In the 1953 tests Krilium 9
was used, whereas in the tests being described the newer
Krilium 212 was used since it could be sprayed and therefore
could be used.more easily. According to Monsanto Chemical
00., Krilium 212 is two to five times more effective than
Krilium 9. _

The original data and the statistical analysis for the
mineral soil tests are shown in the Appendix.

A clear picture of the process to which the soil is sub-
Jeeted is shown in Fig. 28. At (a) the strip of soil to be
processed has been picked up and at (b) the sugar beet seed

rim. " A

 

 

 

61

 

 

Fig. 28. Steps in mechanically processing soil

has just been planted. At (c) the processed soil has again
been deposited upon the ground after the seed has been
planted. At (d) the soil has been compacted by the press
wheel. In this photograph the movement of the machine is
away from the observer. _

The next photograph (Fig. 29) was taken a week after
a 2.5-inch rain. The processed row on the right received a
mechanical treatment plus one pound per acre of GNU. It is
obvious that the mechanical treatment has increased the
amount of crusting of the soil. The crusting is not severe,

but is obviously more than the check row 0 on the left. lo

 

62

 

Fig. 29. Comparison of check row and treated row

attempt has been made here to evaluate this crusting except
by the emergence of the sugar beets.

Figs. 30 and 31 show the damage to the structure more
clearly. The first photograph (Fig. 30) was taken immediately
after the soil was processed, while Fig. 31 is a photograph
taken one year after the soil was processed. It is interesting
to note that in this second photograph of soil structure
damage the soil has partially reaggregated while it remained
in a closed container with no other treatment. This would

indicate that the damage to the soil structure is not permanent.

 

I N0 ,OEOCESSEO .

 

Fig. 30. Soil structure damage immediately after
processing

pEOCESSrJL) NO _
56 OEFM '

 

 

 

Fig. 31. Soil structure damage one year after
processing

61+

In the mineral soil test each block was randomized so

that in the statistical analysis the effect of location in

the field could be removed from.the treatment effect.

Figs. 32 and 33 summarize the weed counts on the mineral

soil. It is obvious that the herbicides have a greater

effect on mineral soil than.on muck soil.

The LSD is rather

large, yet most of the treatments were significantly lower

than the check plots.

To have made this test more complete

the chemical tests by themselves should have been included,

but this would have created more work than could have been

accomplished in the allowed time.

For comparison purposes the work of Grigsby (12) and

Ilnicki (17) is included in Tables XVI and XVII in the

Appendix. However, in this form these tables are somewhat

difficult to compare with Figs. 32 and 33 therefore the

information from the two tables and the two figures has

been combined into Table IV for easy comparison.

TABLE IV

swam OF FIGS. 32 AND 33 COMPARED WITH TABLES XVI“ AND XVII*

 

 

Sum of grass and broadleaf weeds
expressed as percent of check

 

 

Herbicide Herbicide
alone plus mechanical
TCA 10 lbs/acre hB 26
CMU % lb/acre 70 108
Endothal 2 lbs/acre 50 9h
Endothal h lbs/acre h2 llO

 

“From data by Grigsby (12) and Ilnicki (17) respectively.

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67

Only four of the treatments could be compared, but
these are sufficient to show that the effect of the mechanical
treatment in combination with the herbicides is no greater
than the chemicals by themselves.

The emergence of the sugar beets with the various
treatments is shown in Fig. 3h. It was stated earlier that
the purpose of this information was to show the tolerance
of the crOp to the treatment. However, the emergence of
the sugar beets is of no particular value since the combination
of the herbicide and mechanical treatments has been shown
to be no more valuable than the herbicide treatments alone
as far as weed control is concerned. I

In Part II it was mentioned that the mechanical plus
Krilium treatments resulted in a significant increase in
the emergence of sugar beets in the 1953 tests. However, in
l95h all treatments resulted in a decrease in the emergence

as compared to the check plot.

Discussion of lfiShgfield tests

In Fig. 33 it is disturbing to note that most of the
treated plots contained more grass than the check plot. It
is possible that this was the result of a mischance in
sampling of the check plot, or perhaps the scarifying effect
on the weed seeds more than offset the effect of the herbi-
cides.

In three of the four comparisons on mineral soil the

6'6

 

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69

combination of herbicide plus the mechanical treatment
resulted in less weed control than the herbicide alone. In
one case the apposite was true. When TCA at 10 pounds per
acre was applied in combination with the mechanical treatment
it resulted in better weed control than the herbicide alone.

“=1

However, since this is an isolated case it would appear, if

:- "7"?

we consider all the paired data, that the mechanical treat-
ments did not add anything to the herbicide treatments.

“_"77- 1“.“ 2

In Fig. 32 an interesting, but disconcerting phenomenon
is observed. The mechanical treatment alone at 1730 rpm
resulted in a greater'broadleaf weed count while at the
higher speed of 2600 rpm the weed count was much less than
the check plot. In neither case is the difference from.the
check plot significant. However, the difference between
the two mechanical treatments is significant. .The discon-
certing aspect of this phenomenon is that the result is
Opposite to that obtained in the greenhouse tests using
muck soil (see Fig. 18). .

The emergence of the sugar beets is shown in Fig. 3h.
It should be noted that all the treatments reduced the
emergence of the sugar beets as compared with the check
plot. However, in only one-third of the treatments was the
reduction in emergence significant.

A reduction in the emergence of the sugar beets as a
result of some weed control treatment is not necessarily

serious. A reduction in the pepulation of the crap being

.q

 

/‘l

70

grown will not necessarily reduce the yield unless the pOpUp
laticn drape below the optimum. In the case of sugar beets
the Optimum pOpulation is about one plant per ten inches of
row when the rows are spaced 28 inches apart. However, if
the weed control treatment seriously stunts the plants, then
the yield.may be reduced even though the plant pOpulation is
at the Optimum. A betteereasure of the effect of the weed
control treatment upon the cr0p being grown is to actually i
measure its yield, but time did.not permit this. Therefore,
the next best measure of the effect of the treatment upon
the crop was used. That next best measure is the emergence
of the planted crOp.

The treatments of Krilium plus mechanical processing
reduced the emergence for all three rates of Krilium. Two
of the three Krilium treatments significantly reduced the
emergence. This reduction in emergence is in contrast to
the results obtained in 1953 when the Krilium significantly
increased the emergence of sugar beets. In 1953 Krilium 9
was used while in l95h.Krilium 212 was used. .

No explanation can be given for the fact that the effect
of the Krilium plus mechanical processing in 1953 was
opposite to the effect in 195k. The weather may have had
an effect. In 1953 a one-half inch rain fell soon after
planting followed by dry weather. In l9Sh the planting was
followed by two weeks of dry weather and then a 2.5-inch
rain fell. There is also the possibility of a mischance in
sampling.

 

CONCLUSIONS

1. There was no reduction in the weed pOpulation in
the 1953 field tests when using the centrifugal machine to
process muck and mineral soil in the field.

2. A significant increase in the emergence of sugar
beets was obtained in the 1953 field tests when the mechan-
ically processed soil was mixed with Krilium 9‘at the rate
of 0.1 percent by weight of the soil processed.

3. In the greenhouse tests the centrifugal machine
significantly decreased the number of weeds at low impeller
speeds and significantly increased the number of weeds at
high impeller speeds when processing muck soil.

R. No significant changes in the weed pOpulation
could be detected when using the laboratory impact device
to process the soil. Neither the height from which the
weight was drcpped or the thickness of the soil being pro-
cessed had any effect.

5. During the l95h field tests the mechanical treat-
ments alone resulted in no significant weed control in both
muck and mineral soil.

6. During the l9Sh field tests most of the chemical
treatments in combination with mechanical treatments signifi-
cantly decreased the weed pepulation. However, the decrease
in weed pOpulation was no greater than that obtained by

chemical treatments alone.

72

7. During the 195# field tests the Krilium 212 soil
treatments applied by use of the centrifugal machine signifi-
cantly reduced the sugar beet emergence in two of three
rates. This is in contrast to the 1953 field tests in.
which the emergence was increased when using Krilium 9.

8. The review of literature indicates that for each

seed there is an impact velocity which will reduce the

~. 84’. A .- ofi‘esunq

germination of that seed a specified amount depending upon

its moisture content.

4" ‘-. A

DISCUSSION AND RECOMMENDATIONS FOR FUTURE WORK

Although the data presented here is almost entirely
negative, it isfelt that the possibilities have not been
exhausted for using mechanical energy to process soil for
‘weed control.

1. Research most certainly should be continued on the
engineering aspects of weed control with emphasis upon the
control of those weeds which grow in the row.

2. Equipment should be devised to subject the soil to
shear to determine its effect upon the weed seeds.

3. Tests should be conducted with mineral soil similar
to those described in Part III of the investigation using
the centrifugal machine at a wider range of impeller speeds.

h. Static crushing tests should be made on several
sizes of seeds including weed seeds to determine the force
and energy required to fatally crush theseeds.

5. If the equipment can be devised, impact velocity
tests on various seeds should be made to determine the per-
cent reduction in germination. These impact velocity tests
should determine the effect of seed size and the moisture
content as well as the impact velocity upon germination
reduction. Seventy-five to 100 percent germination reduction

would be required for satisfactory weed control. However the

 

.mnm;._v_

 

,1

71+

same type of infonmation applied to grain grown for seed
should include the range from zero to 20 percent reduction
in germination. This type of information applied to field
crOps would be useful in the design and Operation of seed
handling and processing equipment including combines.

6. In order to use the type of information listed
under item 5 for weed control, it would be necessary to
determine the equilibrium moisture content of weed seeds
in the soil. .

7. When.mechanically processing the soil, the damage
to the soil structure becomes important, however no
attention should be given to this subject until a practical
method has been found to mechanically sterilize the soil.

Fig.1 .1... Val: .mJ .

. J ILL

APPENDIX

Mathematical Analysis of Soil Particle Velocity Attained when
Accelerated on a Centrifugal-Impeller

Kincgmderived this equation of motion (1)

(Id - [4/131 —/- Z ’L/ at.» Va " J‘ Jack :7. c/ +,(,.' Sir/ff.) : C 0)
for a partigle being accelerated by a centifugal tLade rotating
on a vertical axis.. This equation is a general equation which
considers the shape and the length of the blade, but does not
consider air resistance. For a straight radial blade, which

the design described in this report closely approximates, he

shows that this equation reduces to:

Z .
,{J‘ - ... 7 , 15'
[£2 + w /~/ ‘ [/1 " a-“ V : C' (II)

t «It

This equation applies to a centrifugal impeller illustrated

by this schematic diagram.

The solution to equation (2) is:

—rr/L:J/Z73/Jt' ._u'(,L“-VLI+7) 1‘ \3)

l ' ...- ’ __ _s ‘ J
_. — K . I .g\ K -. K .
\

and when differentiated yields

...}

xwm; A.- _—

.D' l p

P.” _.
,.
"_ .

_...

«c.

, / ____ \‘ -(I'(/(—‘+ix/"Iz'fl‘ x,
I: — -r-c¢-,c-+Jx»u») e: ,

 

mil. , e- / J\

.Je / . . _ \ 3 /
---—-—-- -..“, —/,J J it . (4)

 

.\

"' / 0 " |
_.. C ..J, ‘ ,7 , c— ‘y ' ? ' I ‘D’ .I
,_ ‘ (.4. ‘x. [L [[1 I / / 2

These two equations (5) and (4) cannot be solved directly

J

forft'in terms ofrr, but by trial substitution for values of

I
w-

and by applying boundary conditions, it can be shown that the

second term can be ignored when considering slide rule accuracy,

so that we have:

_J_J-_'“ : 'r ' (1’ ......

Lit [v'f’l/i'z’}./
For example, when

 

f: : If.) #31717...) (1/.:"/ l3~ / /'/'
u: a Z’ Ki: I'c’?c'//rr//,r:3/J .1“

IL) 3' C" 4 if!" 90-f/j‘5/i», 7L (7" //'/.. 5/} [,4
\ J

thenJJL' . 1540 inches/sec.

dt .
The velocity tangent to the impeller is
V2.: f‘U‘ =- 2720 inches/sec.

and the total velocity is 3270 inches/sec.

 

TABLE V

1953 FIELD TEST DATA. MINERAL SOIL PROCESSED

WITH CENTRIFUGAL MACHINE

78

Number of weeds in each sample of 100 in. row by h in. wide
Count made on July 22, 18 days after planting

 

 

 

 

 

 

 

 

Replication Treatment
SIKO c1 SlKl C2 SzKo ° 82K1 on
1 l 0 1 0 0 h 0 l
2 0 3 l 5 2 0 0 S
3 l 2 2 3 2 0 -
h 1 5 0 0 l 2 1
TABLE VI
ANALYSIS OF VARIANCE OF 1953 EMERGENCE 0F SUGAR BEETS
0N MINERAL SOIL”
Source of Degrees of Sum of Mean
error freedom squares square
Total 19 21,258
Treatment 12,571 2,51h
Replications 3 6,h01
Error 11 2,286 208

 

*See Table I

 

tl

TABLE VII

79

WEED COUNT AND STATISTICAL ANALYSIS OF GREENHOUSE TESTS
USING CENTRIFUGAL MACHINE ON MUCK SOIL

 

 

Replication l

Replication 2

Replication 3

 

Grass Broad— Total Grass Broad- Total Grass Broad- Total

 

 

 

 

leaf leaf leaf
0 9* 9 3o 39 35 166 181 21 62 83
D181 8 38 #6 9 73 82 20 63 83
D182 _8 36 in 22 87 109 19 67 86
D133 23 #3 66 111 201 312 9 52 61
Dish 58 1&4 202 66 201 267 22 159 181
D281 6 32 38 no 63 103 25 85 110
D232 8 21 29 39 92 131 15 E2 57
D283 13 27 no 188 218 366 25 61 86
Dash 76 128 206 108 173 277 105 286 391
D381 15 26 81 11 E1 52 22 hz 6h
D332 11 26 37 11 MO 51 11 SO 61
D333 5h 33 87 35 32 67 36 93 129
DBSu 63 68 131 65 68 133 u? 108 155
Analysis of Variance of Total Weeds per Plot
Source of Degrees of Sum of Mean
error freedom. squares squarepA‘ ”F"

Total 35 321,888 9,200

Replications 2 h0,h28 20,21h

Speed 3 132,950 uu.300 9.5**

Depth 2 29,077 18,500 3.1

s x D 6 15,950 2,660

Error 22 103,883 h,700‘

(10) in the 1%

**Indicates that speed is highly significant or that this
value of F is larger than the tabulated value given in Goulden

column

_ '00 .51

80

TABLE VII Continued

Table Summarizing Data from Greenhouse
Centrifugal Machine Test

 

 

 

 

 

 

Depth in Impeller speed in rpm
inches 31 g 32 33 Sh Total Average
lhOO 1870 2600 3470
D1 = 1/2 211 239 1139 650 1539 128
D2 = 1 251 217 1192 872 1832 152
D3 = 2 157 1119 283 819 1008 811
Total 619 605 12111 19111 11379
Average 69 67 135 215 122

 

Pa,- -.:__~.v yum. Aim-s

k--

 

«IA-Elam)“

Al-

.‘ Sly-1 :

.....-

 

TABLE VIII

EMERGENCE PER 100 INCHES.

81

1958 FIELD TESTS 0N MUCK

Treatments 1-13 on sugar beets and 1h—l9 on onions

 

 

 

 

Treatment” Replication Average
1 2 3 h
1 30' 31 3o 28 29.8
2 31 21 20 8 20.0
3 32 2h 25 30 27.8
u 30 28 22 25 26.2
Ch- ' 35 L10 21. 28 31 .8
5 33 31 13 26 25.8
6 12 32 23 29 24.0
7 6 13 19 19 lh.2
8 15 10 10 8 10.8
9 22 u 19 13 1h.5
10 a 10 10 6 7.5
11 17 18 11 20 16.5
12 13 19 1h 16 15.5
13 6 19 6 10 10.2
In 125 118 106 172 130.2
15 180 1h? 122 11A 130.8
16 103 88 10h 89 96.0
016 19h 186 160 108 151.0
17 93 33 #6 Sh 56.5
18 185 139 108 Sn 120.5
19 100 59 60 50 67.2

 

*See Fig. 26 for eXplanation of treatments

Fl.__n-

a new -q mam—“.3
r’"

‘14—.
fl

82

TABLE IX

NUMBER OF BROADLEAF‘WEEDS PER SQUARE FOOT.
1958 FIELD TESTS ON MUCK

 

 

 

 

Treatment* 1 RZplicatiog h Average

1 56 58 72 60 61.5

2 81 73 68 55 69.2 J
3 66 35 28 38 60.8 3
L|_ 27 33 37 ' 1+2 311-8
Ch 3h 28 57 125 60.0 i
S h? 33 26 55 A 80.2

6 15 13 21 28 19.2

7 10 7 2h Bk 18.8

8 29 30 81 56 89.0

9 56 20 28 17 29.2

10 19 10 13 17 18.8

11 31 17 9 In 17.8

12 22 11 12 13 1h.5

13 9 22 18 11 15.0

14 12 h 7 6.8

15 6 11 u 5 6.5

16 7 6 10 86 17.2

016 12 37 23 18 22.5

17 23 88 16 10 28.2

18 10 82 21 26 28.8

19 12 55 81 15 80.8

 

”See Fig. 26 for eXplanation of treatments

l.>sml a. ..

 

33

TABLE X

NUMBER OF BROADLEAF'WEEDS PER SQUARE FOOT.
1958 FIELD TESTS ON MINERAL SOIL

 

 

 

Treatment” Replication Average
1 2 3 A 5
1 18 27 1 8 3 11.8
2 18 8 5 16 3 9.2
3 1 2 2 u u 2.6
L. 22 27 6 12 2 13.8
5 23 15 1 8 6 10.6
6 20 33 u 10 1 13.6
7 3O 81 6 18 5 28.0
8 20 13 12 8 7 12.0
9 31 h 19 3 3** 12.0
10 E7 30 10 25 3 23.0
11 20 u 7 10 5 9.2
12 11 25 O 7 1 8.8
13 63 83 7 1h 13 36.0
1h 21 29 3 u 17 18.8
15 21 28 0 25 16 18.0
16 22 26 7 15 13 16.6
17 30** AZ 5 19 10 21.2
C 29 67 19 18 16 29.8

 

“See Fig. 32 for explanation of treatments
**Missing data supplied by Goulden's (10) method

*2‘_
.3
,r
i

r” 19“ :1 .‘lr‘fi‘:
.Iu
-—_ .. .

 

81+

TABLE XI

STATISTICAL ANALYSIS OF BROADLEAF WEED COUNTS
ON MINERAL SOIL. 1951+ FIELD TESTS

T 1
_L L

H

Analysis of Variance
(completed values)

 

 

 

 

'58;;;;_;E_¥ Degree§kof Sum of;
variation freedom squares
Total 87 23.381
Treatments 1? S,hSl
Blocks n 8,113
Error 66 9,817

 

Analysis of Variance
(corrected for.missing data)

 

 

 

 

Source of Degrees igaaggs 333820 "F“
variation freedom
Total (original) 87 23,008
Error (completed) 66 9,817 lh8.7
Blocks + treatments 21 13,191
Blocks (unadjusted) a 7,989 .
Treatments (adjusted) 17 5,202 306 2.06
051.713)...— W733) = ;/ 118-«3 = 7.72
LSD = (t) ((51-53) (2.0) 7.72 = 15A

for comparing any two treatments except 9 and 17

 

 

—“1_—‘

TABLE XII

Replication

NUMBER OF GRASS WEEDS PER SQUARE EOOT.
19511 TESTS 0N MINERAL SOIL

 

 

 

85

 

Treatment” 1 2 3 h 3:; Average
1 A7 '76 15 17 76 52.2
2 56 118 12 511 611 116.8
3 2 16 u, 9 30 12.2
11 19 27 L1 35 30 23.0
5 113 30 9 36 38 31.2
6 35 13 3 15 10 15.2
7 22 72 6 79 113 1411.11
a 31 31 28 52 78 15.2
9 65 78 38 17 63** 52.2

10 £19 33 26 211 1411 35.2
11 7 2 12 9 6.8
12 10 2 1 15 22 10.0
13 27 53 38 65 36 13.8
11+ 27 65 21. 26 67 111.8
15 28 38 10 76 65 213.1,
16 19 6E 50 59 51 14.8.6
17 60“ 87 20 76 79 611.11
c 13 39 6 55 38 30.2

 

*See Fig. 32 for eXplanation of treatments

issing data supplied.by Goulden's (10) method

7
I
h.

 

!
gz

TABLE XIII

STATISTICAL ANALYSIS OF WEED COUNTS OF GRASS
0N MINERAL SOIL. 1951; FIELD TESTS

86

 

 

 

 

Analysis of Variance
(completed values)

 

 

 

EEE;:;_3? Degrees of Sum of
variation freedom squares
Total 87 50,263
Treatments 1? 23,326
Blocks A 10,8hh
Error 66 16,093

 

Analysis of Variance
(corrected for missing data)

 

 

 

 

Degrees Sum of Mean
Source or of squares square "F"
variation freedom
Total (original) 87 h8,920
Error (completed) 66 16,093 2th
Blocks + treatments 21 32,827
Blocks (unadjusted) h 10,652
Treatments (adjusted) 17 22,175 1’304 5.3**
K. W _—
"" = 2A.“. 1 l = 9093
T -T ._ .-
( 1 3) L 5 + 5
LSD = (t) r = (200) 9093 = 1909

(Ti-T3)

for comparing any two treatments except 9 and 17

2?

F277”? 3: r. n P“ can- rm.r

_...“

_..—A.-

‘1

37

TABLE XIV

+
SUGAR BEET EMERGENCE PER 300 INCHES.
1958 FIELD TESTS ON'MINERAL SOIL

fl
__-t “'7

#:-

 

 

Replication Average
Treatment” 1 2 3 h 113;. 1066is.
1 30 39 70 63 99 2091
2 25 73 82 98 88 Zhoh
3 1 1 1h 3 No 3.9
A 6A 130 55 106 A6 26.8
5 17 21 89 111 67 20.6
6 23 It 69 95 A6 26.5
7 17 17 113 120 AB 21.0
8 80 102 ~ 131 111 108 35.2
9 33 105 115 132 103** 32.6
10 16 an 116 90 100 27.1
11 61 7A 116 116 70 29.2
12 26 311 79 119 73 25.11
13 E6 38 83 101 86 23.?
1h 67 23 105 106 6N 21.3
15 L10 35 ‘ 100 50 1211 23.3
16 10 32 81 17 65 13.6
17 29** 30 88 83 107 20.6
c . 5 170 112 117 88 36.8

 

:Sum of three loo-inch samples
*See Fig. 32 for explanation of treatments
“*Missing data supplied by Goulden's (10) method

 

88

TABLE XV

STATISTICAL ANALYSIS OF SUGAR BEET EMERGENCE.
195k FIELD TESTS 0N MINERAL SOIL

 

 

Analysis of Variance
(completed values)

 

 

 

Source of Degrees of Sum of Mean
variation freedom squares square "F"
Treatment 17 31,8hh. 1,850 1055*
Blocks A 19.751
Error 66 78,u67 1,190
(7’1 ._ = 1 190 1 1 = 21.9
(Ti'Tj) W' ('5' + 3')
LSD (300 inches) = (t) ar' = (2.0) 21.9 = 13.3
LSD (100 inches) = h3.8 = 18.6
3

”The Treatment sum of squares has not been corrected
for missing data, but this is not necessary since the
correction.wou1d make the Treatment sum.of squares smaller
and therefore "F" would be smaller. "F" is not significant
unless greater than 1.8.

 

89

TABLE XVI

EFFECT OF PRE-EMERGENCE HERBICIDE TREATMENTS UPO§
ALL WEEDS IN SUGAR BEETS GROWN ON MINERAL SOIL

 

 

Number of broadleaf

Herbicide Rate . and grass weeds
(percent of check)

 

TCA 5 lbs/acre A 67

TCA 10 lbs/acre A8 ??

Endothal 2 lbs/acre 50 E)

Endothal h lbs/acre 42 .

Check 100 A.
L}

 

 

*Data from unpublished report by Grigsby (12)

TABLE XVII

EFFECT OF PRE-EMERGENCE HERBICIDE TREATMENTS UPON
WEEDS AND SUGAR BEETS GRowN 0N MINERAL SOIL”

 

 

 

 

 

 

 

 

Sugar beets

 

Herbicide Rate (% of stand) Weed control

CMU 2 lbs/acre 10 ---

CMU l lb/acre 85 I ---

CMU i lb/acre 100 70 percent

TCA 5 lbs/acre -- Good grass and
smartweed control

TCA 7% lbs/acre -- Good grass and
smartweed control

TCA 10 lbs/acre stunted

TCA 15 lbs/acre stunted

 

*Data from unpublished paper by Ilnicki (17)

IIIIIIIA

  

3“ . ,1
M; . 4 pl.

Jr MUNLHM H

GLOSSARY

Definition of units and terms

 

Impact Velocity - The velocity with which the soil
particles and weed seeds hit the impact plate

K E = Kinetic Energy = %MV2

Theoretical horsepower z iMVZ/sec.
550 ft-lbs/Sec.

where mass is in slugs
and V is in fps

 

LSD Least Significant Different

(to 05) x (Standard Deviation for the difference
0

between two treatment averages)

Difference for significance between averages of
any two treatments unless a one in twenty mis-
chance in sampling has occurred.

Herbicide - A chemical known to be toxic to some
chlorophyllebearing plants

Soil Conditioner - A material which improves the
physical preperties of the soil

Pre-emergence applications - Those made after the crOp
is planted but before it emerges

Emergence - The number of plants per 100 inches of row
which emerge from the soil and continue to live
Description of chemicals used

Krilium 9 - A soil conditioner made by Monsanto Chemical
Co. A carboxylated polymer in powder form.

Krilium 212 - A soil conditioner made by Monsanto
Chemical Co. A carboxylated polymer powder
soluble in water.

CMU - 3-p-ohlor0pheny1-l-l-dimethy1urea, a herbicide.

 

91

CIPC - IsOprOpyl-N-(3-chlor0phenyl) carbamate, a
herbicide.

TCA - Trichloroacetic acid, a herbicide.

Endothal - 3,6-endoxohexahydr0phthallic acid, a
herbicide.

Dalapon - DichlorOprOpionic acid, a herbicide.

l.

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3.

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5.

7.

8.

9.
10.

11.

REFERENCES CITED

Bainer, Roy and H. A. Borthwick. Thresher and other
mechanical injury to seed beans of the lima type.
Calife Ag. EXPO Stae Bull. 580, JUly, 1934.

Bass, C. M. Viability of injured weed seeds. Proc.
Assoc. Official Seed.Analysts 30:

Borthwick, H. A. Thresher injury in baby lima beans.
Je Agre R08. uh: 503-510, 1932.

Bunnelle, Philip R. Combine performance in small
legume seed harvesting. Unpublished paper presented
at ASAE Annual Meeting. Minneapolis, Minn. June 21-
2A, 1954. Dept. Agr. Engr., U. of Calif., Davis, Calif.

Carleton,‘Walter M. Principles affecting the perform-
ance of mechanical sugar beet planters. Unpublished
Ph.D. Thesis. Michigan State College, l9h8.

Chepil, W. S. Germination of weed seeds; the influence
of tillage treatments on germination. Sci. Agr. 26:

317-157. 19116.

Cotton, R. R., and J. C. Frankenfeld. Mechanical force
for the control of flour mill insects. Amer. Miller,
OCtOp 19u2.

French, George W. A double-counter rotating-head
mechanical sugar beet thinner. Mich. Agr. Exp. Sta.
Quar. Bull. 3“: “OB-ull, May, 1952.

Case, W. L. The vitality of buried weed sedds.
Jo Agr. ROBe 29: 3&9'3929 192“.

Goulden, Cecil H. Methods of statistical analysis.
2nd ed. .JothWiley'& Sons, Inc., New York, 1952.

Grigsby, B. H. Unpublished Annual Report.’ Weed
Division, Bureau of Plant Industry, USDA. Submitted
Feb. 1, 1951 from Michigan State College, East
Lansing, Michigan.

 

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13.
. 1A.
15.
1.;

17.

18.

19.

20.
21.

22.
23.

2h.

25.

93

Grigsby, B. H. Unpublished Annual Report. Weed
Division, Bureau of Plant Industry, USDA. Submitted
Feb. 1, 1953 from Michigan State College, East
Lansing, Michigan.

Harter, L. L. Thresher injury a cause of baldhead in
beans. J. Agr. Res. AO: 371-38u, 1930.

Boise, A. C. "Germination of common ragweed seeds.
Proc. Assoc. Official Seed Analysts 35: 67-68, 19AM.

7:21

Heise, A. C. Germination of green foxtail seeds.
Proc. Assoc. Official Seed Analysts 3h: AB, 19h2.

Huyett, R. B. Shot peening. Steel Processing 33:
553-557. 19h7.

Ilnicki, R. D. and Willard, C. J. Unpublished paper
presented to North Central Weed Control Conference.
Kansas City, Mo. Dec. 8-10, 1953. Workers from
Ohio Agr. Exp. Sta. Ohio State Univ., Columbus, Ohio.

’ f“ it" u '0 ‘V‘mt'h:

C-

Johnson, C. E. and Wright, K. T. Reducing sugar beet
OOfitSe Miche Agr. EXPe Sta. Ciro. B‘Jlle 215. June,
19 9.

Keen, Bernard A. The physical properties of soils.
Longman, Green Go Co., New York, 1931. p. 272.

Kinch, D. M. Physical factors affecting the germi-
nation vitality of weed seeds. 'Unpublished Ph.D.
Thesis. Michigan State College, 1953.

Koehler, Benjamin. Corn seed-coat injuries increase
seedling blight. Ill. Agr. Exp. Sta. 95Year Report,
1938-19h7. pp. 28-29.

Newhall, A. G.‘ Theory and praCtice or soil sterili-
zation. Agr. Eng. 16: 65-70, 1935.

Nichols, M. L. The dynamic preperties of soil. II.
3011 and metal friction. Agr. Eng. 12: 321-32h, 1931.

Porter, R. H. and.Katherine Koos. Germination of
injured weed and crap seeds. 'Proc. Assoc. Official
Seed Analysts 28: 68-73, 1936.

Smith, F. R. Method and apparatus for destroying
insect life. U.S. Patent NUmber 2,339,732, 19th.

911

26. Splinter, W. E. A consideration of weed control through
physical prOperties of seeds. Unpublished.M.S. Thesis.

27. Tools, E. H. and M. Brown. Final results of the duvel
buried seed experiment. J. Agr. Res. 72: 201-210, l9u6.

 

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2.

3.
h.
S.
6.
7.
8.
9.

10.

11.

12.

OTHER REFERENCES

Bainer, Roy and J. S. Winters. New rinciples in
threshing lima beans. Agr. Eng. 1 : 205-206, 1937.

Chepil, W. S. Germination of weed seeds: longevity
periodicity of germination and vitalit of weeds in
cultivated soils. Sci. Agr. 27: 307-3K6, 1986.

Church, Austin.H. Centrifugal pumps and blowers.
John.Wiley & Sons, Inc., New York, l9uh.

13‘7““ '1 -.J 703—,—

Cross, HOpe. ’Laboratory germination of weed seeds.
Proc. Assoc. Official Seed Analysts 2h: 125-128, 1931.

Plain-e... -‘ Ai"~7
i _
w '3. .

Entoleter. Continuous insect control. Engineering
Specifications. Form No. 399hc-6-u7. Entoleter
Division. The Safety Car Heating and Lighting Co.,
Inc., New Haven, Conn.

Heise, A. C. Report of sub-committee on the evaluation
of weed seeds. Proc. Assoc. Official Seed Analysts

323 81-h2. 1980.

Hibbs, Arthur H. and R. B. Dodds. Continuous insect
infestation and insect fragment control. Modern

Hentschel, Herbert E. A study of principles affecting
the performance of mechanical sugar beet planters. '
Unpublished.M.S. Thesis. Michigan State College, 19h6.

Hodgson, J. M. Electrocution of weeds, widely adver-
tized, not successful in Idaho field experiments.
CrOps and Soils 3: 25, Dec., 1950.

Koehler, Benjamin. Corn pericarp injuries and seedling
diseases. PhytOpath. 36: h03,

Koehler, Benjamin. Seed-coat injury in hybrid corn
causes yield losses. I11. Agr. Exp. Sta. Ann. Report,
1937-1938. p. us.

Lambert, D.‘W., et a1. Devitalization of cereal and
weed seeds by‘EIgE—frequency. Agron. J. 82: 30A-
306. 1950.

13.

1A.

15.

16.

96

Patten, H. E.‘ Heat transference in soils. U.S. Dept.
Agr. Bull. 59. 1909.

Swanson, S. L. w. and H. G. M. Jacobson. Influence of
cultivation and weed killers on soil structure and
crOp yield. ’Soil Sci. 69: hhS-hS7, 1950.

Thompson, V. J. Sub-committee report on the viability
of injured weed seeds. Proc. Assoc. Official Seed
Analysts 31: 70-71, 1939.

Whitney3'W. A. Mutilated seed - a Contributing factor
in defective stands of lima beans. (Abstract).
PhytOpath. 20(1): IBM-135. 1930.

 

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