5-1074
August ‘I968

     
   

, A f“
¢ \\

 i: the Effects of Certain
PREC|S|QN PRACT|CES

on the Efficiency
of Cotton Production

TEXAS A&M UNIVERSITY
Texas Agricultural Experiment Station
H. O. Kunkel, Acting Director, College Station, Texas

SUMMARY

A careful evaluation of the conventional system
of field crop production indicates that a tremendous
potential for increasing production efficiency exists
by overcoming or minimizing the following deficien-
cies:

(l) Normal yields are less than 70 percent of
the potential yield in many fields because of variations
in production among individual rows and areas
within the fields.

(2) More than 5O percent of the plants in a
typical cotton field will bear less than 25 percent
of the total yield.

(3) Non-uniform growth and plant development,
particularly during the early part of the season,
reduce the effectiveness and efficiency of many of
the cultural operations.

(4) The overall efficiency of the harvesting
operation is reduced by the non-uniform rate of
maturity among the plants along the rows and among
the rows which will either result in a delayed harvest
for the major portion of the fruit or the harvest of
a high moisture product.

Investigations and analysis of present produc-
tion procedures indicate that many of the factors
that influence the variables can be related directly
to the performance and operational characteristics
of machine components. The lack of a means of
maintaining precise control over the movements
and operational characteristics of the principal soil-
working components is one of the basic problems.
Nonuniformity of seed placement combined with
the micro-environments to which the seed are exposed
during the germination and emergence periods are
principal factors contributing to variability in emer-
gence, growth, maturity and yields.

Department of Agricultural Engineering field
experiments have shown that it is feasible to establish
and maintain precision control surfaces that can be
used by properly designed sensing and controlling
devices to maintain precise control over the move-
ments of the implements in the vertical and hori-
zontal planes. The following operational character-
istics of the machine components and equipment
indicate increases in efficiency and effectiveness that
can be achieved:

(1) From 5O to 100 percent reduction in soil
movement in field operations with an overall increase
in efficiency and effectiveness of soil working tools.

(2) More precise control over seed placement
in the vertical and lateral planes within the intended
seed zone.

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(3) Significant increase in speed an‘
(4) Significant reduction in power at

(5) Establishment and: maintenan _
favorable environmental conditions ~-'
germination and growth of the planted

Crop response to the new approa ti
indicated by the following: ‘

(1) Increased uniformity in rate of
(2) Increased total emergence. 

(3) Increased rate and uniformity
and maturity. 
(4) Reduced sensitivity of the pl:
ation to climatic factors that influence ,1
and emergence. 

(5) Increased production, ranging 
cent to 44 percent with an overall ave "
of 28.2 percent.

c o N

Summary ......................................................... .5
Introduction .............................................. .-

Analysis of the Conventional
Production System ................................. ..

Land Preparation ................................ 
Planting .................................................. ..
Post-emergence Operations ................ 
Crop Response ....  .............................. .. "

Development and Construction of Pr f
Control Surfaces ......................................... .

Forming Precision Shaped Seedbeds”:
Precision-Depth Planting ................... ..
Evaluations of Planting Methods .... 
Emergence .......................................... .. l
Soil Temperature ............................. .. 
Cultivation and Other Cultural Practic)
Acknowledgments ....................................... ... 

the Effects of Certain

PRECISION PRACTICES

on the Efficiency of Cotton Production

 
  
  
  
 
  
 
  
  
  
 
 
 
  
  
 
  
 
 
 
  
 
  
  
 
  
 
 
  
 
 
  
  
 
  
 
 
 
  
 
  
  
  
 
  
 
  
  
 
  

' D EQUIPMENT HAS PLAYED a major role in
~ ing the high degree of efficiency which is
5 d in field crop production. The most
_ tribution of mechanization to the overall
has been the dramatic reduction 0f labor
I ts. Practically all phases of crop produc-
been mechanized. That is, most of the func-
erly performed by hand labor and animal-
uipment are now being accomplished with
"ity motorized equipment and chemicals.

-. most operations have been mechanized,
 trends for the immediate future to combat
y rising cost of labor will be in the develop-
1_ use of larger equipment with higher ca-
Unless the fields and farms are sufficient
 permit efficient operation of the larger
ftional cost involved may nullify the in-
vings. The success of past research and
 ts has greatly diminished potentials for
the efficiency of present production systems
» e development of new machines.

fetbulletin reports research developments of
‘tment of Agricultural Engineering at A8cM
1.; approach to field crop production. Cotton
used as the principal test crop. However,
. should be adaptable to most major field
'- e intensive investigation and analysis of
‘entional production system defines and
 some of the major recurring problems
g i“ machines.

Qnew approach is based on the principle
achine is limited in its performance only
ill of the operator or the control plane
I is designed to follow, regardless of the
it or precision encompassed in the machine.
‘ufacturing industry has been successful in
izing many of the production systems by
 this principle. In most cases, where the
“is been automated with a machine following
‘n reference plane or pattern, the quality
quantity of the products are normally su-
_; those produiied with similar equipment
y. and operated by skilled labor. In order
achines to operate effectively as independent
i e type of guidance or control mechanism
established-such as a reference plane, track,
for template. A high degree of precision
 incorporated in the control mechanism,

Lambert H. Wilkes and Price Hobgooo|*

which in turn, determines the uniformity and ac-
curacy of the machine.

Research in the Brazos River Valley near College
Station has dealt with the establishment and main-
tenance of precision control surfaces for use in field
operations. Implements have been developed to
utilize the potentials this approach offers. Control
surfaces have been highly effective in providing pre-
cise control over critical movements in the vertical
and lateral planes. In addition to the precision that
has been obtained, a significant increase in crop
productivity has resulted.

ANALYSIS OF THE CONVENTIONAL
PRODUCTION SYSTEM

A critical examination of the current production
system reveals that most of the practices and equip-
ment have evolved from those employed when animals
were used as the chief source of power. Land prepa-
ration, planting and cultivation procedures and
equipment are basically the same. Much of the human
energy and all of the animal power have been replaced
with mechanical energy. Equipment and procedures
have been modified to function at higher speeds,
which modern tractors can obtain. Larger power
units have also made it possible, in many instances,
to combine several functions into one operation.

In mechanizing field crop production, many of
the machines have retained their basic operating
principles. During the era of animal power, the
operator was responsible for the performance of a
single unit. As more power has become available,
his responsibility has increased, according to the
number of rows the power unit can handle. These
responsibilities add to those required in operating
the tractor or power unit.

In field operations, there are two distinct planes
in which the movements of the implements are
involved. These include the vertical and horizontal
planes. The effectiveness of most functions of

*Respectively, associate professor and professor, Department of
Agricultural Engineering.

3

machines depends on the machine components being
held at a relative and constant position in the two
planes to a selected reference while in operation.
Normal references used in field operations include
the soil surface, prepared furrows or seedbeds and
the planted crop. \

The lateral position of the machine components
in the horizontal plane depends entirely upon the
operator's skill while the equipment is moving.
Previously prepared furrows or ridges and the planted
crop- are normally used as the reference by the
operator to steer the tractor. Individual row com-
ponents in a multiple-row machine are mounted in
fixed positions laterally along tool bars, which the
tractor supports. This arrangement causes the entire
machine to» function as a rigid unit in the horizontal
plane. The effectiveness of practically all operations
—including cultivation, flaming, chemical and fer-
tilizer app-lications and harvesting-depends upon the
operator to maintain the operating component of
the machine in a fixed position relative to the crop.
In many cases, the effectiveness and resulting effi-
ciency of field operations can be increased by main-
taining closer tolerance-s than most operators can
maintain.

Position of the machine components in the verti-
cal plane is normally maintained at a selected distance
from the soil surface. Position of the components,
with respect to depth of penetration or height above
the surface, is normally sensed and controlled through
the tractor wheels, gage wheels on tool bars or small
gage wheels on individual row components. Precise
control over the relative position is also important
in all cultural practices, including cultivating, chemi-
cal and fertilizer applications and harvesting. Al-
though the principles of sensing and controlling the
vertical movements of the components are sound,

Figure 1. These are lister-formed seedbeds before planting.
Typical variations in sizes and shapes among the rows, along
with the rough, irregular surface, prevent using precision plant-
ing and production techniques.

4

 

  
   
   
   
  
    
   
 
 
 
  
  
   
  
   
 
 
 
  
  
   
 
   
 
 
    
 
 
 
 
  
   
    
   

conventional land preparation and cultural
do not permit effective use of the system. w
field operations, such as with sweep cultiva
ations of surface profiles make it necessary?
and use greater penetration depths than
required. This is to insure that the coma:
effective in all parts of the field.

Rate of travel is also?‘ a major factl
efficiency and effectiveness “of the machin
is critical in operations where chemical, see
tilizer applications are involved. Travel spe’
fects the effectiveness of the tillage implemi
as the cultivator. Most tractors are equir
adequate governing systemsto maintain s‘
operator selects. One of the principal fa

determines the selected speed is the operat”
and skill. 
Land Preparation

Field crop-s in the humid areas of g
normally planted on raised seedbeds to pro  i
age away from the seed in case of exce
after planting. This method is generall
to as “bed planting.” The seedbeds are f0
listers or row disks several months before
so that the normal spring rainfall will p
ficient moisture in the soil for germin“
emergence. Although the listed beds 
satisfactory in providing the desired en‘,
for the planted seed, profiles of most seedb, ,
be used effectively as control planes for i t‘
A typical field which has been prepared f0,
is shown in Figure 1. The beds appear to bee‘
uniform in shape and size. However, me:
taken at random locations in a typical 
shown that cross-sectional dimensions, 
height and width, may vary as much as 
These dimensions along a single row have 
to vary as much as 4 to 6 inches in differe
of a field. These irregularities are oft,‘
aggravated by tillage operations for control
that occur on the beds before planting.
the uniformity of the profiles may be im‘
operating the bedding equipment more f.
the rounded profile and the loose soil on 
have not satisfactorily provided the precisi’
in most operations. a
Planting '
A typical planter, which has been usedlii
ly for planting on the listed beds, appears i
Most of the planters used in multiple ro
are suspended through flexible linkages
bars attached to the tractor. A large whe
planter operates on the convex surface o
and helps control vertical movements of i,
vidual planters. Immediately behind the 
is a wide sweep, which removes loose, dryé
the crest of the beds and establishes a new,
elevation and profile. i

Because of nonuniformity of the 

  
    
   
   
 
 
  
 
 
  
  
 
 
 
 
  
  
  
 
 
 
  
 
  
 
 
  
 
  
  
  
 
 
 
  
  
 
 
 
  

a, The conventional row-crop planter used for planting
~ seedbeds uses a large sweep t0 remove loose dry soil
"_ crest of the listed beds. Amount of soil removed by
~ is determined by the depth of moist soil required for
on and emergence o-f the planted seed. A chisel type
 ener forms the seed trench. Chisel covering shovels
iigthe moist covering soil.

th to moist soil from the surface varies con-
ply. Since it is not practical to compensate
}varying depths of dry soils, maximum depths
ally selected so that all seed are placed in
h This removes more soil than necessary
 areas of the field and causes principal com-
‘ of the planter, including the furrow opener
 ering device, to operate in high moisture soil.

a nting depth is determined from the new
 the sweep establishes. The furrow opener is
"a to the desired planting depth and is secured
f ed position relative to the sweep. Small chisels
11g on each side of the seed furrow provide
covering soil for the seed.

 eral problems related to seed placement in
 have not been solved in the mechanization
 Although some improvements have been
yd with other devices for forming the seed
 in the conventional planting system, these
“t been great enough t0 overcome the practical
f of the chisel type opener. As with most
‘implements, moisture content and soil type
 affect the performance of the opener. Scour-
let and sticky soils is the most difficult problem
 openers. It is difficult to form a clearly
 seed trench. Measurements taken at random
Ans within a field have shown that the cross-
Sal dimensions of a seed furrow are often 50
I percent greater than the opener.

in intensive study 20f seed furrows created by
nventional planting system has shown immense
on in seed distribution and in the resulting
nment to which the seed are exposed. In
‘in to the scatter within the planting zone, the
lie of this zone to the surface of the covering
 fective planting depth) has varied as much as

1 inch in different areas of the field. Bulk density
of the soil in the seed zone, which has been used to
indicate intimacy of contact between the soil and
seed, has varied as much as 78 percent. Soil tempera-
tures to which the seed are exposed are also an
apparent variable that causes nonuniform emergence.
Seed scatter in the vertical plane, coupled with vari-
able depths of the seed zone along the row, results
in the seed depth range of 1 to 3 inches. Tempera-
tures may vary as much as 1° F. to 3° F. between the
two depths. Soil samples in the seed zone have shown
that moisture content of the soil has been relatively
uniform and apparently is not a critical factor in the
conventional planting system.

Large press wheels usually compact the surface
of the beds after planting. Compacting the covering
soil retards the drying rate and improves to some
extent the soil-to-seed relationship. Extra large drum-
type rollers are also used in some instances to improve
the surface profile of the beds to help subsequent
cultural operations.

Post-emergence Operations

Many cultural operations depend on the success
of the planting operation and surface profiles. Most
common to all crops is mechanical cultivation. Other
practices include application of herbicide, flame,
fertilizers and insecticides. For maximum effective-
ness in most of these operations, a high degree of
control should be exercised. Many o-f the herbicides
are applied as directed sprays to minimize possible
crop damage. The same principle applies to the use
of flame cultivation to control weeds among crop
plants along the drill. The maximum potential and
extensive use of many of the new practices have been
handicapped by the lack of uniform surfaces, Figure 3.

Figure 3. Non-uniformity of the listed seedbeds, combined with
the lack of a suitable means of controlling the vertical and
lateral movements of the planters, results in extremely irregular
row profiles. The effectiveness of early-season cultivation is
severely reduced because it is difficult to select an ideal setting
of the cultivators to compensate for the variations in profiles
among the rows.

The only practical means of accomplishing the post-
planting operations in a field without uniform sur-
faces is to rely on the operator's skill. Speed and
effectiveness of the operation are severely affected
while the plants are small. Where the row profiles
have been destroyed, elevated sections of the rows
are normally reconstructed by gradually moving the
soil to the base of the plants with cultivating imple-
ments. In most areas a depressed area between the
rows for channeling irrigation water and for drain-
age, in case of excessive rains, is needed.

Crop Response

Difficulty in maintaining positive control over
the functions of conventional production machines
often relates to the uniformity of emergence of plants,
rate of growth, maturity and production among indi-
vidual rows and plants within a field. Variations
in plant emergence among consecutive rows that
often occur are shown in Figure 4. Rows from which
the emergence data were obtained were planted with
a four-row machine. The two areas were selected
in the field along the same rows to illustrate how
the performance of planters may vary in different
sections of the field. Usually, no established pattern
of variability exists among the rows. This makes it
difficult to detect the exact causes.

AREA NO. I

 

ROW |
ROW 3
ROW 4

3 ROW 2

O

t!

h.

o

l-

: 6 8 |o I2 l4

u_ DAYS AFTER PLANTING

o AREA NO. 2

l!

LU

O.

,"_’ now 2

z ROW 3

j ROW 4

CL ROW I

 

6 8 IO I2 I4
DAYS AFTER PLANTING

Figure 4. Variations in the performance of conventional plant-
ers is illustrated by plant emergence patterns. The data were
taken from the same four rows in two areas of a field. These
variations stem basically from the performance of the opening
and covering devices, which the moisture content and soil type
influence.

6

m YIELDS PER ROW 
n: . 
oz _‘
4° a
0-20- f
5:; F  
0.0 ’
o3 A l
J: l5" 1
m“ i
;0 a f’
fig 
<1 .

2o s»-
32 =
o .
LLI _'
I 2 3 4 5 6 7 8 9 IO ll, l2 ll‘

CONSECUTIVE ROWS

Figure 5. Graph shows typical variations in yields;
of cotton. The difference in maximum and minim

varied as much as 100 percent. Variations are;
uniformity of emergence and final stands in di I
of the row. These data indicate that the potentiaf»
be increased by approximately 35 percent by 0bta'

production among the rows. "

Yield data from individual rows all’

signficant variation in equipment perfo 
ton yields obtained from consecutive ro i
have shown that production from the r0 
as much as 100 percent in some areas o
Difference in yield is partly because of 
plant populations along the row. i

Another important variable measure
fields is the productivity range among
Other factors, in addition to planting and"
practices, could influence the plant grow i
ing habits. The productivity range amon
termined by the number of bolls per pla V,
cal cotton field is shown in Figure 6. As A



NUMBER OF sous/PLANT

'7'.» OF TOTAL PLANTS
0 N :-

I I
o
n:
ul 
5 
u| 
m 
~ 

Figure 6. Productivity among cotton plants vari p
within a given stand or field. Variations do not/
related to varietal characteristics, since similar tr
recorded in several cotton varieties. Plants that p”
bolls or less represented approximately 50 percent-
population. The yield from this portion of the sta

only 24 percent of the total. 

  
   
 
 
  
 
  
  
  
 
  
  
 
 
  
  
 
  
 
  
 
 
 
  
  
 
 
  
  
  
  
  

/
/
I
/
/
/
/
/
\’ /
\0€t /
/
/
/
I / 
, / \-
/
I
/
I
l l l l l l | I l
IO 2O 3O 40 5O 6O 7O 8O 9O IOO
PLANTS" °le

i 7. Percent of yield, as distributed among the plants
‘factual field conditions, contrasts with an ideal stand, in
itotal yield is distributed uniformly among the plants.

l. of the plants produced no fruit at all. Plants
iroduced eight bolls or less represented 49.9 per-
 the total plants. However, the yield from this
i,» of the stand represented only 23.8 percent
if total yield. Actual distribution of the total
among the plants is contrasted to an ideal stand
fich the yield is distributed uniformly among
ants in Figure 7. Identifying factors that cause
fl or non-productive plants, which would either
ve the productive capacity or be eliminated
s seed stage before planting, has a tremendous
M itial for increasing production efficiency. It
rd be emphasized that the low producing plants,
 as the low producing area of the field, received
N e cultural treatments during the production
as the more productive plants and areas.

 DEVELOPMENT AND CONSTRUCTION or
 PRECISION CONTROL SURFACES

he initial phase of this research was for obtain-
ore precise control over the planting depth.
he research progressed, approaches and techniques
in obtaining precision in the planting were also
ed to other cultural operations.

n developing an overall system, special consider-
 was given to the following objectives: (1) de-
ing and maintaining uniform surfaces to control
fl and lateral movements of the implements;

lion that is expected and required by machines
'ng the surface; and (3) developing row profiles
provide the environment required for germi-
‘n, emergence and, growth of planted crops in
i'd areas. i“ "

 he fields in which this research was conducted
been prepared with listed beds formed in the
ntional manner. Several methods and machines
f, used in the initial stages of the research to
lish a flat, smooth surface on the crest of the

fveloping control surfaces which exhibit the.

listed beds. Equipment included drum-type roller,
bed planes (drags) and conditioners. In some fields
with uniform listed beds, using bed conditioners
followed by the drum-type rollers provided a satis-
factory surface on the beds for adapting precise
planting techniques, when compared with conven-
tional planting equipment and practices. Although
flat surfaces formed this way were satisfactory in
some instances for controlling planting depth, the
beds did not provide suitable surfaces which could
be used for controlling lateral movements of the
planter and other implements.

Forming Precision Shqped See-dbecls

The most effective control surfaces were obtained
with precision formed or shaped seedbeds. The De-
partment of Agricultural Engineering designed a
bedshaper, Figure 8, for listed beds in the humid
areas. This was because commercial shapers were not
available in the area. “Bedshaping” has been asso-
ciated with a wide variety of bed-forming equipment.
However, in this research, it refers to forming seed-
beds with precise dimensions in the horizontal and
vertical planes. The implement used in forming the
beds is basically a leveling and molding device, which
creates the desired profiles with smooth surfaces.
Forward components of the shaper accumulate soil
from the high points along the sides and tops of
the listed beds. Soil which is accumulated is then
deposited in the low sections along the row, establish-
ing beds with uniform profiles throughout the field.

Several operational characteristics to be con-
sidered for successfully using this equipment in soils
in the humid areas have been established. Listed

Figure 8. The two-row precision bedshaper was designed and
built at A8t-M. Four-row shapers have been constructed and
used in a wide variety of soil types. A dry soil mulch is neces-
sary in the heavy clay soils to prevent moist soil from coming
in contact with the shaper. A

7

beds must be relatively uniform in height and shape.
The shaper can compensate for variations of 3 t0 4
inches in height and width for distances l0 to 15 feet
along the row. One of the principal problems en-
countered was scouring in heavy soils. Using drum
rollers in heavy soils immediately ahead of the shaper
to reduce the bed height reduced this problem
in most cases. The generation of a loose, dry soil
mulch over the listed beds with mechanical equip-
ment has been necessary in some fields to reduce
the scouring problem and to help operate the shaper
properly. A way to adjust the pitch or attitude at
which a shaper is operated must be available, since
this feature can be critical in moist soils. Adjusting
the top link in a standard three-point hitch system
was suitable.

Design of the shaper determines desired shapes
of the row profiles, including height, width and
slopes of the beds. Much experimentation with
various configurations showed that most listed beds
contained sufficient soil to form a bed 4 to 5 inches
high and 20 inches wide. The 20-inch horizontal
surface has been adequate for maintaining precise
control over the movements of the implements in
the vertical plane during planting and other produc-
tion operations. Height of the precision beds was
adequate for maintaining lateral stability of the pro-
duction implements.

Precision shaped seedbeds have been formed
with the A8cM bedshaper in several soil types, includ-
ing Lufkin Fine Sandy Loam near College Station;
the Miller Clay and Norwood Silt Loam in the Brazos
River Valley; and the Houston Clay in the Blackland
areas of Texas. The beds have been highly effective
in providing the desired control surfaces for planting
and the various cultural operations. It should be

CONVENTIONAL ,, BED-SHAPING
m 4O |

I "l

DECEMBER-JANUARY
I

 

APRIL

Figure 9. The conventional planting system is compared sche-
matically with the precision system. Research shows that the
beds should be shaped in enough time before planting, so that
normal rains will provide the moisture required for planting.
Moisture must be available at a uniform depth from the surface
at planting time. A precision depth planter should be used on
the shaped bed to realize the maximum potentials of the system.

8

 
   
 
 
  
  
     
  
   
  
  
   
   
 
  
    
    
    
  
   
   
    
    
  
  
 
 
  
  

emphasized, however, that maximum pot
the precision shaped seedbeds will not be
unless planters and cultural equipment desi
this approach are used. ‘A

The time at which beds are shaped in;
to planting is an important factor. Equip
ployed to maintain a uniform planting dep
adequate moisture for germination and i
at uniform depth from thelsurface of the sh
The most practical way to achieve this ob
the humid areas has been to shape the beds
planting, Figure 9. The time interval bet
two operations depends upon the expected:-

Once the precision beds have been f0 
in the intended seed zone should not be 
Preplant weed control should be accompli
soil-incorporated herbicides, flaming or 
oils. The firm, undisturbed surface must su
planters and provide positive control over
ing depth. The dry surface also mini
scouring problem with the furrow openers,
the openers to form a precision shaped seq

Precision-depth Planting L

The need for greater precision in pl
been demonstrated in some basic studi
involved the effects of certain micro-envii
factors upon germination and emergence 
seed. These factors include soil temperatl
ture and intimacy of contact between the;
soil. The principal problem in these studies
relating laboratory findings to field resul
of varied conditions that often occur ‘A
rows, as well as along a given row, in diff
sections. if

This research has chiefly tried to obt 
precision in seed placement in lateral . i‘
planes of the seed zone. No efforts have:
voted to longitudinal seed placement, since’
commercial seed were used in the research.’

A planter was designed and constructe;
the top surface of the precision-shaped b
reference plane to maintain precise contro
penetration depth of the furrow opener, ;
Two semi-pneumatic gauge wheels were 
the depth control mechanism. Gauge p
placed as close to the opener as practi
mediate response to surface variations.

The seed furrow opener is the most f
ponent of the planter. After the seed »
metered from planter hoppers, they are l’
free-fall into the soil. The shape or co ‘A
of the furrow is, therefore, the chief facto;
trols lateral and vertical seed displacem
intended placement zone. Field evalua
several types of openers show that the -=‘
opener, along with its ability to scour in y
are the principal factors that govern the fu f,

 

~l A precision-depth planter was designed and con-
‘for precision-shaped seedbeds. Only the furrow opener
 or disturbs the soil. Penetration depth is controlled
' wheels adjacent to the modified runner opener. A seed
Peel may be used to press the seed into the mo-ist soil to
 the relationship between the soil and the seed. An
“ter press wheel is used to cover the seed. A piece of
g resistant plastic on the trailing edge prevents moist
 from sticking to the opener.

lative effectiveness of three types of openers
ing seed furrows on precision shaped beds are
irted in Figure ll by resulting seed distribution
 Furrows formed by the standard chisel
y resulted in only 33.3 percent of the seed
pg] ed in the desired zone. The double disk
3 _- provided good seed control in the vertical

SEED FURROW OPENERS

DOUBLE
DISK

CHISEL

 

*1'/el~
SEED CONCENTRATION
IN TARGET ZONE

64.5 °/.>

33.3 ‘v.

 Design and operational characteristics of seed fur-
jfners in various soil types are principal factors that
 e seed distribution in the horizontal and vertical planes
Iseed furrow. When operating on pre-shaped seedbeds,
fified runner opener gave the highest seed concentration
he intended planting zone. Poorest concentration was
Q with the chisel opener. Field emergence of cotton
little differences between the modified opener and the
ers, even though the seed were scattered more in the
lane.

    
  
    
  
   
 
  
  
   
  
  
   
   
  
   
   
   
    

  
     
    

Seed Tube

  

iRear Mounting
Bracket

Begin Taper at
Leading Edge

30° (angle of seed furrow)

Figure l2. Diagram illustrates principal construction features
of the modified, runner-type furrow opener. The shape of the
opener was designed to act as a sliding wedge to minimize soil
disturbance and to fo-rm a firm “V”-shaped trench. The point
of the wedge started at the leading edge of the opener and
expanded gradually to the trailing edge.

plane. The seed, however, were scattered over a
l-inch lateral span. Approximately 65 percent of
the seed were located in the intended zone. The
highest degree of uniformity was obtained with the
modified runner opener. Approximately 80 percent
of the seed were concentrated in a cross sectional
area of 1/3 inch square. The modified opener, Figure
l2, moves like a sliding wedge in the soil, forming a
“V”-shaped furrow. An open center press wheel easily
closes the furrow after the seed have been deposited.
Seed press wheels pressed the soil around the seed
to retard the loss of moisture and obtain positive
contact between the soil and seed. This attachment
was used effectively with the modified and double
disk furrow openers. It was not effective with the
chisel opener.

Evaluations of Planting Methods

The precision-depth planting system has been
evaluated in field experiments to test pro-cedures and
equipment against the principal variables that nor-
mally affect the performance of the equipment and
crop being planted. Variables included soil types,
soil temperatures and rainfall following planting.
In each field experiment, the conventional planting
system was included for comparison. Such factors
as seeding rate, seed quality and variety, planting
depth and operating speed were the same for the
two planting methods. Performance of the planted
crop has been used as the main indicator to evaluate
the planting system. Measurements of micro-environ-
mental conditions in the seed zone were made where
feasible.

Emergence

Plant counts were made at periodic intervals
during the emergence period to evaluate effects of

9

i PRECISION BEDS

noo-
[I] couvzuruoum.

b Q
o o
I I
J_
_ 
J
—?;l

20*-

TOTAL EMERGENCE, ‘k PLANTEO SEED

O1
O
I
1
iii__»__ __ _ __v_ I

I 2 3 4 5 6 7 8
FIELD EXPERIMENT NO.

Figure 13. Effects of planting methods on total emergence of
cotton are shown. Soil types, minimum soil temperatures and
rainfall conditions encountered in each experiment are sum-
marized in Table 1. Overall average emergence was 74.4 percent
for cotton planted on precision beds with the precision depth
planter, as compared with 46 percent with the conventional
planter.

planting methods on rates of emergence and total
emergence. Plant emergence data have been expressed
as percent of planted seed. Effects of the two planting
systems on maximum plant emergence in eight of
the field experiments are given in Table 1 and pre-
sented graphically in Figure l3. Principal variables,
including soil types, minimum soil temperatures and
rainfall, during the emergence period for each of
the experiments are given, Table 1. Typical emer-
gence patterns obtained with the two planting systems
under different climatic conditions are illustrated
in Figures 14 and l5. Maximum plant emergence
obtained with the conventional planting system

TABLE 1. A SUMMARY OF THE FIELD EXPERIMENT IN WHICH THE PRECISION PLANTING SYSTEM 
PARED WITH THE CONVENTIONAL PLANTING SYSTEM 

I00»- PRECISION sens
---- convzunount

LU
2 °°P
3
K
UJ
I
u 60»-
b-
Z
DJ
U
I
a’ 40-

2o-

L l 1
o 2 4

DAYS AFTER PL ANTIN 6

Figure 14. Graph shows emergence rate of cotton "
by the two planting systems when the average of.‘
minimum temperatures at seed depth was 64.5° F. w‘ A
during the germination emergence period. Alth
emergence was equal, the emergence rate was grea
pre-shaped precision beds. "

ranged from 23.4 percent to 72.6 percen
the same climatic conditions and soil types, u;
emergence ranged from 67.3 percent to l7
with the precision-depth planter on shal”
Overall average emergence of the eight
was 46 percent of the planted seed with th‘
tional planter, as compared with 74.4 perce
precision planting system. The greatest Q‘
between the two systems were obtained i‘
periments where low soil temperatures '
occurred during the emergence period. T_
gence data reflected little differences between;
methods where the mimimum soil "I
averaged 64.5° F. or higher with no rain. 4'

Field Soil Maximum
experiment Soil temperature Rainfall Planting emergence

no. Year type °F1 inches’ system percent
l 1964 Norwood 66.4 .00 Conventional 72.6
Silt Loam Precision beds 79.3
2 1965 Norwood 63.5 .00 Conventional 67.8
I Silt Loam Precision beds 67.3
3 1966 Norwood 58.2 .76 Conventional 41.3
Silt Loam Precision beds 80.0
4 1966 Norwood 59.4 4.12 Conventional 23.4
Silt Loam Precision beds 78.4
5 1966 Miller Clay 58.2 .75 Conventional 39.0
Precision beds 72.4
6 l966 Houston Clay 1.25 Conventional 24.2
Precision beds 68.4
7 1967 Norwood 61.2 .45 Conventional 57.2
Silt Loam Precision beds 74.5
8 1967 Miller Clay 62.5 .55 Conventional 52.5
Precision beds 74.7

‘Average of the minimum daily soil temperature at 2-inch depth during the germination and emergence period.

zTotal rainfall during the first 5 days after planting.

l0

 
   
  
 
  
 
  
 
 
  
   
 
  
  
 
  
 
 
  
 
 
 
 
  

   

PRECISION BEDS

,/" couvsunouna.

   
   
   
 
 
 
 
 
  
   
  
  
   
  
 
  

I I I I I I I
a no I2 l4 l6

I’ z
' DAYS AFTER PLANTING

U. Emergence rate of cotton appears as affected by
ilanting systems, when minimum daily soil tempera-
 ged 62° F. during the emergence period. Total rain-
'proximate1y 3 inches during the germination period.
' g caused significant reduction in rates and total
 of cotton planted with the conventional planter.

e faster, however, with the precision system
 periments, even under favorable climatic
ns.

iperuiure

‘ eased effectiveness of the new planting system
uted to the improved micro-environmental
} s into which the seed were introduced.
icontrol over the vertical movement of the
. ow opener results in uniform planting depth.
mbined with the high seed concentration

sou. TEMPERATURE - ‘F
2"DEPTH
APRIL 2o, use:

.0 /,/'4:\

i‘ so / \

l / \

.. / \

1 \

D

I; 1o \-
K /

h]

l

z ‘N

:1‘ so

' convzunonnl. esos
PRECISION BEDS -i-——-u1iu—
5O
I I I 1 I I I
2 4 6 B IO l2 2 4 5 9 |Q |g
ILM. NOON RM,
Figure 16. Soil temperatures were recorded on an hourly basis

at the 2-inch depth in the conventional and precision seedbeds
after planting. Temperatures indicated that a greater amount
of radiant energy was absorbed and retained in the precision
shaped beds, when compared with the conventional beds.

within the planting zone, as in Figure 11, exposes
more seed to the same micro-environment within the
seed furrow. The precision seed trench also permits
more intimate contact between the seed and soil,
which, in turn, increases the absorption rate of heat
and moisture.

The increase in radiant energy absorbed by soil in
precision beds, as compared with conventional beds,
has been a major factor in the effectiveness of
the new planting system when soil temperatures are
a limiting factor. Soil temperature records were kept

i.‘ SOIL TEMPERATURES DURING TWO 8-DAY PERIODS RECORDED IN THE CONVENTIONAL AND PRE-
iiB-EDS DURING THE 1965 PLANTING SEASON IN THE BRAZOS RIVER VALLEY

Soil temperatures — °F — 2-inch depth

ES

Minimum Maximum Averagel Degree-Hours Per Day’
Conventional Precision Conventional Precision Conventional Precision Conventional Precision
Planting No. 1. March 27, 1965
47 45 71 75 59.0 60.1 27 55
62 62 79 84 67.5 69.0 94 131
55 54 81 86 66.3 67.1 115 148
56 55 80 84 65 .5 66.4 86 116
54 55 78 81 65.5 66.0 101 118
64 64 72 74 67 .5 68.3 66 86
66 66 69 70 67.1 67 .5 52 60
66 66 79 82 71.5 72.3 150 169
58.8 58.3 76.1 79 .5 66.2 67.1 86.4 110.4
Planting No. 2. April 16, 1965

61 63 75 76 67.4 68.3 72 84
64 64 86 86 72.0 72.2 170 174
67 67 87 89 75.9 76.9 162 285
70 71 85 87 75 .6 7 6.9 254 285
71 72 83 85 75.9 77.4 262 297
72 72 81 83 75 .4 76.7 249 281
72 72 86 89 77.4 78.7 297 333
72 72 92 95 79.9 81.9 359 406
68.7 69.1 84.4 86 .6 74.9 76.1 241 268

  
 

iiof hourly temperatures during 24-hour day.

ours represent number of degrees above 65° F. accumulated each hour during the 24-hour period.

l1

0n an hourly basis during the germination and emer-
gence period for several small scale plantings. Ther-
mocouples used as sensing elements were placed with
the seed in the soil 2 inches deep with both planting
methods. Soil temperature records were normally
valid for periods up to 8 days after planting. After
the seedlings began to emerge, soil around the
thermocouples was disturbed. Erratic readings were
obtained after this period. Typical soil temperatures,
which were recorded during a clear day, are shown
in Figure l6. Table 2 summarizes daily soil tempera-
tures recorded during two germination and emergence
periods.

Minimum daily soil temperatures at seed depth
were approximately the same in both planting
methods. Maximum temperatures at seed depth,
however, ranged from 1-4° F. higher in the precision
bed. The average of the daily maximum temperatures
for the first planting, Table 2, was 34° F. higher in
the shaped beds than in the conventional seedbeds.
In the later planting with higher daily temperatures,
the difference was 22° F. Additional heat energy
absorbed by the shaped beds was retained and re-
sulted in a temperature differential of 14° F. for
periods up to 1O hours per day. Heat energy accumu-
lated each day in the seed zones is expressed in degree-
hours in Table 2. The degree-hour system of indi-
cating differences in heat energy absorbed in the seed
zones reflects differences in temperatures and the
time in which higher temperatures occurred. Values
are determined by accumulating total number of
degrees each hour that the temperature was above
65° F. An overall average of 26.5 more degree-hours
were accumulated per 24-hour day in the precision
beds than in the conventional beds, Table 2.

Further evidence of crop response to the precision
system of production has been indicated in the rate
of plant growth, root development and rate of ma-
turity and yields. Differences in plant growth rates
are usually quite apparent in the first 3O to 45 days
after planting, Figure 17. Plant measurements on two

Figure 1'7. Difference in rate and uniformity of cotton growth
experienced in several plantings is evident. Cotton on the left
was planted in shaped beds. That on the right was planted in
conventional beds. The test was in the Blackland area near
Thrall.

12

PRE-SHAPED. esoa
uoomeo PLANTER
[Icouvaunouat PLANT,
PERCENT or YliEfii-‘D
I000 —
w
q; 72.2 54.0  
o 
< 800- 
\ 
m -
2
s00 -
:>
a T‘
ii 400- T‘
Z
_l
200 -
SEPT. 9 00T. ||

HARVEST DATES

Figure 18. An increase in the maturity rate has been p,
with the precision planting system, as reflected by the pe I
of the total yield harvested in the first mechanical f’
These data were taken from the planting made in ex
No. 2 in Table 1. Eight hundred and twenty-five p0
lint cotton, representing 72 percent of the total yield, A
at the first harvest in the precision planted plots, as c 
with only 550 pounds representing 54 percent of the t0 _
in the conventionally-grown cotton. f’

of the plantings have shown that the average?
heights on the precision seedbed were 25 "i
percent greater than the plants which emeri
the conventional system. Final plant hei 
harvest have been approximately equal. In s i,
the experiments, the increase in rate of pl
velopment has been reflected in maturity 
cotton, Figure 18. 

In 1967, cotton plants from both planting 
were extracted by hand from adjacent rows 
replicated blocks. The soil was Norwood Silt
Tap root length was measured from the If
soil contact on the stems to where the rootsi
when pulled from the soil. Average lengthi
main roots on the plants from the plots on ,
cision beds was 9.12 inches, as compared wi;
inches for plants grown in the conventional
tion system. Besides difference in root leni
percent of the roots from the conventionally-p 
cotton had some deformity. Only 17 percent]
plants from the precision beds had similar d?
tap roots. The malformed roots consisted of‘ j
twisted roots, abrupt changes in direction of
and plants which had no main tap roots. 

   
  
   
 
  
  
  
  
 
 
  
 
 
  
 
  
 
  
  
 
  
  
  
 
 
  
 
  
 
  

INCREASE m PRODUCTION
g as
15ml |s.a I 2&5] ate I 44.1 I 3a.: 2a.:
.51 2 a 4 s 1 AVERAGE
_   PRECISION sens
Ii couveunoum.
e, ll U“
l f l. _
2 I a 4 I a 1 AVERAGE

FIELD EXPERIMENT NO.

9. Cotton yields were obtained with the two planting
‘ r six experiments. Increase in yields obtained in the
3 planted system over the conventional system ranged
 to 44.7 percent.

 were obtained from six of the eight field
lents, in which the two planting systems have
ympared. These data are given in Table 1
isented graphically in Figure 19. Yield in-
if cotton planted in the precision beds with
 ision-depth planter ranged from 13.8 percent
ifpercent with an overall increase of 28.2 per-
” ield increases were attributed primarily to
 niformity established along and among the
 typical comparison of yields from individual
"tween the two planting systems is shown in
20. In other experiments, variation among
ftive rows in the conventional system have
ifas much as 72 percent, as compared with ll
in the new planting system.

ATION AND OTHER CULTURAL PRACTICES

cision shaped seedbeds, which were used to
Ygreater precision in seed placement in the
A also be used effectively for control planes
pal production operations. Horizontal surfaces
‘A crest of the bells} as well as in the furrows,
3v used as the control plane for vertical
ents. Slanting vertical surfaces on the sides
en used effectively as control planes for lateral
tents. Both gauge wheels and sliding skids
1 en used effectively on the horizontal surfaces
trol mechanisms for the vertical movements.

The basic machine consists of a multiple tool bar
arrangement, from which the various implements
and tools are suspended. The height of the tool
bars can be adjusted in relation to the controlling
mechanism to accommodate the crop and the tools.
Sled-type runners, as controlling mechanisms, have
maintained the selected vertical position of the tool
bars in relation to the soil surface while operating.
They also support the machine weight. Because of the
weight, the horizontal surfaces of the furrows between
the shaped beds have provided the most effective
reference plane for movements in the vertical plane.

Required lateral movements of the machines
were controlled with cone-shaped guide wheels,
Figure 21. The convex surface of the wheels, operat-
ing against the sides of the shaped beds, senses the
changes in the direction of rows. The wheels, which
are fixed in a rigid position to the tool bars, cause
the entire machine to shift laterally in the required
direction.

Field evaluations with this approach for main-
taining control over the critical lateral and vertical
movements of the machine have shown that the
tool carrier must be completely independent of any
tractor movements, except for the required draft in
the longitudinal plane. Machine components are
interconnected to where the entire machine performs
as an independent rigid unit. In these evaluations,
the standard three-point-hitch system without the
stabilizer linkage satisfactorily provided the required
free movement for normal operations.

Four cultivations have been made during a

single growing season with the mafiine shown in
.___ g

YIELD AMONG ADJACENT ROWS
I966

ROW LENGTHS-675' ROW LENGTHS-675'

eo-_cpq_y,‘— _ _

40-

l

20-

YIELD-POUNDS SEED COTTON/ROW
l

ROWS ROWS
BED SHAPED CONVENTIONAL

Figure 20. One of the major factors contributing to yield in-
creases, which have been obtained in the precision planting
system, has been the uniformity of production along the
rows as well as among the rows. Yield increases along the rows
in the precision planted cotton have been attributed to the
uniformity of emergence and final stands. Yield variations
among consecutive rows was 42 percent in conventionally-planted
cotton, as compared with 4.5 percent in the shaped bed in this
experiment.

13

Figure 22. QpLerating frequency was determined by
weed infestations, which usually develppeTl after rains
5E irri ationsd. The shape of the original row profile
was maintanied durng the season with the cultivating
tools so that the beds could be used as reference
planes for subsequent cultivations.

Subjective observations in this research have
indicated that this approach has potential for in-
creasing efficiency in the production operations.
These observations were made concurrently with

Figure 22. This is a side view
of the precision cultivator de-
signed for precision shaped seed-
beds. The cone-shaped guide
wheels maintained positive con-
trol over the lateral movement
of the machine. Precision type
sweeps were used to cultivate the
top surface of the beds. Standard
cultivating disks cultivated sides
of the beds and kept the desired
shape for subsequent operations.
The furrows were cultivated with
standard sweeps. The entire
machine functioned as an inde-
pendent unit.

14

Figure 21. Cone-shaped N‘
wheels operating against:
sides of the beds are 
control lateral movements i
four-row precision planter;
to center the planter drill 
top surface of the pre-
beds. Height of the tool‘.
is maintained in a c0?
position relative to the "-
face by the skid runners. i
complete machine operates-
pendently from the tract‘
cept for the required dra 

a
y, .

conventional equipment operating in the

planted and produced in the conventional m L. a

One of the most obvious differences be *
the two systems was the power requirements i 5 ~
cultivating and planting operations. Approxi;
230 tons of soil per acre being displaced durini’ '
conventional planting operation in removing
crest of the listed beds confirms this. Coverinf
over the seed is also pressed in a separate oper.
from planting in the conventional production sy

  
    
   
   
  
    
   
    
   

i, 'on only is required in the precision
ft the soil that contacts the precision
_ er is displaced or disturbed. Lack of
ofiles, combined with poor depth control
lements, displaces approximately 200 tons
i- acre for each conventional cultivating
This is compared with less than 100 tons
an the precision system, where uniform
crmit the implement to be operated at
gepths without sacrificing the effectiveness
i» ivators.

‘fexperience with this equipment has also
L ed that the cultivator sweeps could be
i closer tolerances than in the conventional
A ich relies upon the operator's skill. In
g» the increase in effectiveness, it was pos-
ltain practical operating speeds of 4 to 6
>hour for the early season operations. This
i v with 2.5 to 3 miles per hour with con-
Picultivators. Increased speeds have indi-
‘ the precision production system can obtain

increases in capacities in acres per hour of 35 to 50
percent per machine.

Two other precision operations have been per-
formed, utilizing the control surfaces of the precision
beds. These include applying systemic insecticides
to the plant stems and in the soil. A rotary brush
applicator developed at A8cM successfully applied
65 percent of the material to the stems of cotton plants
in the precision system. A maximum of only 15 per-
cent was successfully applied in the conventional
production systems. Using precision beds for positive
control, continuous bands of systemic insecticides
have been placed 8 inches deep and 5 inches laterally
from the base of the growing plants. Without a
guidance system, the latter treatments were impracti-
cal. Significant plant damage resulted.

ACKNOWLEDGMENTS

The project in which this research was conducted
is contributing to the Southern Regional Cotton
Mechanization Project S-2.

15

Texas Agricultural Experiment Station

Texas A8cM University
College Station, Texas 77843

H. O. Kunkel, Acting Director- Publications

“'4"5’§‘I'5?”-"F-"
A, , ,

P‘ 
U. S. Depart