LIBRARY»
A 8: M COLLEGE.
CAMPUS.

A23-1139-7M-L180

TEXAS AGRICULTURAL EXPERIMENT STATION

A. B. CONNER, DIRECTOR
COLLEGE STATION, BRAZOS COUNTY, TEXAS

BULLETIN NO. 580 DECEMBER 1939

DIVISION OF AGRICULTURAL ENGINEERING

Mechanical Harvesting Qf Cotton As
Affected By Varietal Characteristics
And Qther Factors

 

L 1 E3 R A R Y
Agrisultural 8x Mechanica! ﬁollege of Texas
Callege Statian, Texas.

i-

AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS
T. O. WALTON, President

It.
Q:-
3D

The inﬂuence 0f cotton’s varietal characteristics on the eﬂiciency of
mechanical harvesting, extracting, and cleaning equipment has not been
fully realized until recent years. During the past ten years the Texas
Station Cotton Harvester has been improved so that it will harvest 94
to 98 per cent 0f the cotton from varieties developed for mechanical
harvesting. Experiments indicate that an ideal plant type is one having
relatively short, short-noded fruiting branches, no vegetative branches,
an open type growth, light foliage,‘ storm resistance, and large strong
bolls spread open enough to permit the locks of cotton to protrude from
the bolls in a ﬂuffy condition and borne singly on peduncles (boll stems)
that will snap easily under tension but withstand plant agitation. In
an effort to combine these qualities into one strain, new types of cotton
are being developed through the process of breeding and selection. Some
new strains developed compare favorably with most of the better known
vlfrieties in quality and lint turnout and, in addition, have the desired
c aracteristics from the standpoint of mechanical harvesting. Many high

/

‘yielding varieties are not adaptable to mechanical harvesting because of

unsuitable vegetative characteristics.

One of the major unsolved problems in harvesting cotton by machinery
is the lack of adequate equipment to remove the green-leaf trash from
mechanically harvested cotton. Improvements in the Station Harvester
and Extractor have resulted in greatly reducing the amount of green-leaf
trash left in the harvested cotton, but further improvements are neces-
sary before the cotton can be carried directly to the gin or bulked without
danger of heating.

Varietal characteristics affecting the eﬂiciency of mechanical cotton
harvesters are shape and height of plant, length and number of branches,
density of foliage, type of boll, whether bolls are borne singly rather than
in fused clusters, storm resistance, ﬂuﬂiness of the cotton, brittleness of
branches and boll peduncles, and height of ﬁrst branches above ground.
Spacing of the plants in the row has also been found to be inﬂuential.

Physical factors and varietal characteristics inﬂuencing the eﬂiciency of
bur extracting equipment are feeding rate, which is determined by yield
of cotton and rate of travel of machine; rate of ﬂow of material through
machine; speed of extractor saws; compactness of material; uniformity
of distribution along saws; agitation of material; amount of burs and
foreign trash; size, shape and weight of bur; degree of boll spread;
ﬂuﬁiness of cotton; storm resistance; and ﬁber drag between seeds.

The cleaning of mechanically harvested cotton is affected by several
factors: previous handling; amount and kind of trash; type of cleaner;
speed of cleaner parts; kind and condition of cleaner screen; rate of
feeding; moisture content; and such ﬁber characteristics as density on
seed, ﬁneness, and length of staple.

Varietal types having medium-length staple and coarse-bodied ﬁber
which is dense on the seed clean much better and produce higher grades
than sparse-linted, ﬁne, longer staple types of cotton.

The grade of mechanically harvested cotton is affected by the amount
of trash; weather conditions; kind of trash; time of exposure; ﬁber
injury by harvester, extractor, cleaner, and gin; and ﬁber characteristics
such as ﬁneness, density, and length.

Harvesting cotton mechanically does not appreciably affect the staple
length of the cotton.

Under comparable conditions of plant type and growth the Texas Station
Harvester harvests equally well cotton producing low or high yields.

CONTENTS
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Equipment and varieties used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Varieties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Factors affecting the efficiency of cotton harvesting machinery . . . . . . 9

Varietal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Mechanical factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Cultural methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Effect of different harvesting methods on the quality of cotton . . . . . . . . 20

Extracting qualities of varieties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 27

Varietal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Mechanical and other factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 32

Cleaning qualities of varieties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33

Varietal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33

Mechanical and other factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Factors affecting the grade of mechanically harvested cotton . . . . . . . . 37

Varietal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Mechanical and other factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 38
Grade differences attributed to mechanical harvesting of different
varieties of cotton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . 39

Snapping qualities of cotton bolls . . . . . . . .". . . . . . . . . . . . . . . . . . . . . . . .. 39

Effect of boll spread on harvesting and extracting qualities, . . . . . . . . 45

Relation of yield to the efﬁciency of the harvester . . . . . . . . . . . . . . . . . . 47

Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

r t» um. “ _.i._ ...i_tn._....-.._, M‘... ......l.__.._..._..__,__._......_' __......__.._..YM EMM._H_M_A_MAA.._M_. __,_____.__. __.._____~ i~

BULLETIN NO. 580, DECEMBER 1939

MECHANICAL HARVESTING OF COTTON AS ‘AFFECTED BY
VARIETAL CHARACTERISTICS AND OTHER FACTORS

H. P. Smith,1 D. T. Killoughﬁ D. L. Jones,3 M. H. Byrom4

The efficiency of mechanical cotton harvesters depends, to a large extent,
on cotton varietal characteristics. Many well-designed cotton harvesting
machines may have failed largely because varietal characteristics were not
given due consideration. The inventors looked upon all varieties of cotton
as just cotton and apparently did not realize that there is relatively as
much difference in varieties of cotton as there is in breeds of horses,
cattle, sheep, or dogs.

When the Texas Station began work several years ago on the mechanical
harvesting of cotton, it was recognized that varietal characteristics played
an important part. It was generally known that a machine without change
in adjustment could not harvest diﬁerent varieties of cotton with equal
degrees of eﬂiciency (4, 5, 6).?’ Consequently, a number of commonly
grown varieties, together with a number of new strains and varieties,
have been tested for their suitability to machine harvesting.

New types of cotton are being developed through a breeding process
of selection, crossing, and back-crossing for the purpose of combining in
one strain as many as possible of the characteristics found to be most
desirable from the standpoint of mechanical harvesting. Each year several
hundred selections and hybrids are planted at both College Station and
Lubbock. Notes are recorded on plant type and vegetative growth, boll
type, leaf structure, storm resistance, yield, earliness, lint turnout, ﬁber
characteristics, and other factors that may appear to aﬂect the adapta-
bility to machine harvesting. The most promising selections and crosses
are increased and tested for their adaptability to machine harvesting,
extracting, and cleaning. The newly developed varieties and strains re-
ported in this bulletin are Ducona, Mebane 95 and 96, Mebane 1.40, Cut
Leaf x Acala, Cut Leaf x Clark, Machaﬁ and Lightning Express x
Westexi

lChief, Division of Agricultural Engineering.

zAgronomist, Cotton Breeding, Division of Agronomy.

“Superintendent, Substation No. 8, Lubbock.

‘Agricultural Engineer, Division of Agricultural Engineering.

5Numbers introduced thus throughout this bulletin refer to the bibliography.

“Mr. H. A. Macha of Tahoka, Texas, found this cotton in 1930 growing in a ﬁeld of Half
and Half. Selections were made for several years by Mr. Macha. Later, about 1936, Mr.
f). L.MJor}iles of the Lubbock Station made selections from Mr. Macha’s ﬁeld and named the
ype ac a.

‘This cross was named Western Early in 1939.

6 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Bulletins 452 and 511 of the Texas Station report the ﬁndings of
these studies from 1927 to 1934, inclusive (7, 9). This bulletin reports
results obtained during the four-year period 1935-1938 and treats largely
of the reaction of varietal characteristics to machine harvesting.

Harvesting dates at College Station for the four years were: 1935,

_ October 8 and 9; 1936, October 14; 1937, August 27 and 28; 1938, Sep-

tember 6 and 7. In 1935 and 1936 the cotton was practically all open
and ready for harvest early in September, but a tractor was not avail-
able on which to mount the harvester.

Figure 1. Cross section of Texas Station Harvester and Bur Extractor.

No tests were made at Lubbock in 1935 because of the drought. The
cotton grown for mechanical harvesting during the three years 1936 to
1938 was irrigated, so that material for tests would be assured. Tests
were made at Lubbock in 1936 on November 12, in 1937 on November 6,
and in 1938 on November 9. Each year light frosts killed‘ some of the
leaves, but considerable green foliage was on the plants at harvest. In
no case were 100 per cent of the bolls open, but most of the green, un-
opened bolls were thrown out with the burs by the extractor.

EQUIPMENT AND VARIETIES USED
Equipment

Texas Station Harvester: The machine used in the studies reported
in this bulletin was ﬁrst described in Texas Station Bulletin 452, page 24,

1932. Improvements made in the machine up to 1934 were enumerated .

in Bulletin 511, page 6, 1935. The principal changes made since 1935
are:

(1) The front bearings for the stripping rolls were mounted at the
lower and front end;

(2) The size of the stripping rolls was reduced from 2% to 1% inches,
outside diameter, and they were constructed of ordinary iron pipe
with a knurled surface;

MECHANICAL HARVESTING OF COTTON 7

(3) In 1937 expanded sheet metal was used in the bottom of the con-
veyor troughs, giving considerably more open space for trash and
dirt to sift through as the cotton was conveyed to the extractor
unit. In 1938 perforated sheet metal was substituted for the
expanded metal. Rectangular slots, é-inch by 1 29/32 inches
with the length of the slots running crosswise the trough,
screened out more green leaves, stems, and trash as the cotton
moved over the slots. Figure _1 shows a cross section of the
machine, ﬁgures 2 and 3 show it harvesting cotton at College
Station, and ﬁgure 4 shows the machine harvesting cotton at
Lubbock in early November 1938.

Figure 2. Texas Station Cotton Harvester and Bur Extractor harvesting and extracting
cotton at College Station.

Texas Station Extractor: This machine was described in Bulletin 511,
page 9, 1935. Figure 1 shows a cross section of the extractor and its
position in relation to the harvesting unit as used in 1938. Figures 2 and
3 show the extractor mounted on a tractor with the harvester. Several
changes have been made in the extractor since 1934, and these are:

(1) An auger was placed in the feed throat to distribute the stripped
cotton along the extracting saw;

(2) Stronger stationary and oscillating ﬁngers were installed to pre-
vent their bending and catching on the extracting saws;

8

(3)

(4)

(5)

(6)

BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Rear view of Texas Station Cotton Harvester and
Burl Extractor showing harvested and extracted cotton in
trai er.

Figure 3.

A reclaiming saw was placed below the stationary and oscillating
ﬁngers and adjacent to the main extracting saw to reclaim cotton
that dropped through the ﬁngers with the burs;

Stationary ﬁngers of spring steel were installed with the ends
curving under and ﬁtting close to the reclaiming saw to direct
the burs and any loose cotton in them under the reclaiming saw;

A brush with 2-inch bristles was mounted at the ends of the spring
steel stationary ﬁngers to deﬂect the cotton in the burs up against
the reclaiming saw and cause it to be more ﬁrmly impinged on
the saw teeth; and

A bur doffer was mounted to the rear of the reclaiming saw to
doﬂ’ the burs and prevent their following the reclaiming saw around
and being crushed between it and the extracting saw.

MECHANICAL HARVESTING OF COTTON 9

Figure 4. The Texas Station Cot-
ton Harvester harvesting cotton
at Lubbock in November 1938.

Texas Station Vertical Cleaner: No changes have been made in this
unit since it was described in Bulletin 511, page 10, 1935.

Varieties

During the four-year period, 1935-1938 a total of 18 varieties, strains
of varieties, or progenies of crosses were tested from one to four years
at College Station to determine the suitability of their varietal charac-
teristics to mechanical harvesting, extracting, and cleaning. Lists of the
varieties tested appear in the various tables. The more promising of these
varieties will be tested further. Several strains of Ducona were tested,
but data are shown only for the parent strain, which is typical for the
variety.

At Lubbock 14 varieties were tested. These included some of the
same varieties that were tested at College Station. '

FACTORS AFFECTING‘ THE EFFICIENCY OF COTTON
HARVESTING MACHINERY

The factors affecting the efﬁciency of mechanical cotton harvesters may
be classiﬁed as follows: varietal characteristics, mechanical factors, and
cultural methods.

Varietal Characteristics

Plant characteristics which may affect the efficiency of any type of
mechanical cotton harvester are as follows: (1) shape of plant, (2) height
gof plant, (3) length of branches, (4) number of branches, (5) density of
ifoliage, (6) type of boll, (7) bolls borne singly or in clusters, (8) storm

 

10 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

resistance, (9) degree of boll spread, (10) ﬂuﬁiness of the cotton,
(11) brittleness of branches and boll peduncles, and (12) height of ﬁrst
branches above ground.

Years have been spent testing varieties possessing variable charac-
teristics, and it appears that an ideal plant type for both the mechanical
stripper and the picker is one having relatively short-noded fruiting
branches 8 to 1O inches in length, no vegetative branches, an open type
growth, light foliage, storm resistance, and a medium to large strong
boll borne singly on a peduncle that will snap easily under tension but
will withstand plant agitation. When a variety has been developed that
will meet these speciﬁcations, it will no doubt aid in increasing the eﬂi-

_ , 2 3 _
Figure 5. Types of cotton plants. Plant 1 has short limbs with bolls borne in clusters;
plant 2 has short limbs with bolls borne singly; and plant 3 has long limbs

with long nodes. Plant 2 appears to be a more desirable type than either
of the others.

ciency of harvesting machinery and in reducing the amount of green-
leaf trash collected, thereby raising the grade of the harvested cotton.
One bad characteristic may be of such nature that it will offset the
good qualities of a number of features. For example, if a variety pro-
duces numerous long branches that overlap between the rows, it would
be diﬂicult for any mechanism to harvest all of the cotton from such a
mass of vegetation folded into a narrow space only a few inches wide.
Also it would be almost impossible for a mechanical device to remove
all the cotton from such a compressed mass of tangled vegetation, even
though all other characteristics were excellent for mechanical harvesting.

 

MECHANICAL HARVESTING OF COTTON 11

Shape of plant: The suitability of a variety of cotton for mechanical
harvesting is inﬂuenced by a number of varietal characteristics. From
the stripper harvester standpoint, the foremost characteristic is plant
type. A variety that produces a wide spreading type of plant with
numerous long vegetative and fruiting branches is not suitable for the
stripper harvester and will reduce the eﬂiciency of the picker harvester.

Figure 5 shows three types of stalk development. Plant No. 1, on the
left, has very short limbs to which are attached clusters of bolls by large
short peduncles. The bolls on such a plant are hard to remove and many
limbs are pulled from the main stalk with the bolls. On the other hand,
the branches are too long and spreading on plant No. 3 and will cause

lower machine eﬂiciency. Plant No. 2 has medium-short fruiting branches

with short nodes, and each boll is borne on a separate peduncle. Such
growth is favorable for either mechanical stripping or picking of cotton.
Figure 6 shows a type selected in August 1939, which has some of the
characteristics of plant No. 2. i

Figure 6. A desirable type of Ducona
plant selected in 1939 for increase.
This plant resembles plant No. 2
in Figure 5. ‘

.at Lubbock averaged less than 2 per cent.

12 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

The original Ducona variety, which is better adapted to machine har- 

vesting than most varieties, was bred for a plant type like N0. 1 in

Figure 5 but, proved objectionable because the peduncles were too strong, 
The object 
of the present breeding program is to obtain a type similar to plant No. 2. ‘i
Data in Table 1 show that for a four-year average at College Station, l
when harvesting Ducona cotton, the machine harvested 94.3 per cent of gj

the bolls were borne in clusters, and the limbs were too short.

the cotton on the plants at harvest.

Height of plant: Medium-size cotton plants up to 36 inches in height

can be handled successfully by cotton harvesting machinery.

be stripped off. Drums on a mechanical cotton picker usually do not

exceed 30 inches in length, and tall cotton plants must be bent down i
This, of course, increases the volume _
Such a condition makes ‘

within range of theppicking units.
of vegetation in contact with the picking units.
it difficult for any mechanical device to remove the cotton from the bolls
which may be folded within.

Data collected but not presented show that the average height of
cotton plants at College Station on uplands ranges from 30 to 32 inches.
At Lubbock under irrigation the plant height averaged from 2O to 24
inches (Fig. 7.) A few plants were above 30 inches in height. The
small plants at Lubbock gave higher average machine eﬂiciency than
the larger plants at College Station (Tables 1 and 2). The lowest efﬁ-
ciency obtained at Lubbock was 94.8 per cent for Burnett in 1936, while
the highest was 99.2 per cent for Mebane 96 in 1937. A study of Table 2
shows that for the three years the loss by the harvester for all varieties
Figure 8 shows a section of
the ﬁeld harvested in 1938 before the cotton lost by the harvester was
picked up. It can be seen that only a few locks of cotton were lost.

Length of branches: The H. X., Rothcamp’s Cluster, Roger’s Cluster,
and Clark varieties have numerous branches with a rather dense foliage

and, as a result, machine efficiency ranged from 84.9 to 89.2 per cent for '

these varieties (Table 1). They do not appear, therefore, so suitable for
mechanical harvesting as varieties such as Gorham’s Lone Star, Mebane
140, Kinsler’s Cluster, New Boykin, Kubela, Mebane 96, Cut Leaf x
Acala, Cut Leaf x Clark, and Lightning Express x Westex. The average
machine efﬁciency for these varieties ranged from a low of 92.0 per cent
for Cut Leaf x Clark to a high of 97.3 per cent for Kinsler’s Cluster
(Table 1). The plant type for these varieties was rangy, with spreading
limbs and considerable foliage. Even though Kinsler’s Cluster gave high
machine efficiency, it was discarded because the plant was too brittle.
Varieties producing branches long enough to meet, and sometimes
overlap, between rows spaced 38 to 42 inches apart, create a close mass
of matted vegetation from which mechanical picking devices have diﬂi-

The tops i
of tall plants will not pass through the stripping rolls before they reach A
the rear end of the rolls, and other tall plants pressing against them .
form a mass of vegetative material and cause much needless foliage to a;

Table l. Varieties of cotton tested for machine eiﬁciency, grade, staple, and acre yield at College Station

Percentage of machine _ _ Acre yield of lint
efﬁciency 0f the Grade Staple 1n 32nd Inches pounds
Variety Texas Station Harvester
1935 1936 1937 1938 Av 1935 l 1936 l 1937 l 1938 l Av. 1935 1936 1937 l 1938 l Av. 1935 1936 1937 1938 Av.
Ducona . . . . . . . . . . . . . . . . . . . . . . . . 92.7 90.7 96.5 97.2 94.3 LM SGO SLM LM LM 30 34 31 31 31 249 136 182 341 227

Gorhanfs Lone Star . . . . . . . . . . . .. 90.6 92.8 92.7 97.4 93.4 LM SLM SLM-l- SLM SLM 29 31 30 29 30 309 55 220 262 212

Kelly's Lone Star . . . . . . . . . . . . . . . 88.3 91.4 97.3 . . . . . . 92 .3 LM+ LM SLM-l- . . . . . . . LM-l- 30 31 30 30 250 69 234 . . . . . 184

H. X . . . . . . . . . . . . . . . . . . . . . . . . . .. 89.2 . . . . . . . . . . . . . . . . .. 89 .2 LM . . . . . . . . . . . . . . . . . . . .. LM 29 . . . . . . . . . . . . . .. 29 287 . . . . . . . . . . . . . .. 287

Rothcamgfs Cluster . . . . . . . . . . . . . 90.5 87.9 . . . . . . . . . . . . 89.2 LM SGO . . . . . . . . . . . . . . LM— 30 32 . . . . . . . . . . 31 342 116 . . . . . . . . . . 229

Roger's Cluster . . . . . . . . . . . . . . . . . 84.9 . . . . . . . . . . . . . . . . . . 84.9 LM— . . . . . . . . . . . . . . . . . . . . . LM—— 30 . . . . . . . . . . . . . . . 30 251 . . . . . . . . . . . . . . . 251

Clark . . . . . . . . . . . . . . . . . . . . . . . . . . 78.5 . . . . . . . . . . . . 93.7 86.1 LM— . . . . . . . . . . . . . . SLM LM 30 . . . . . . . . . . 26 28 306 . . . . . . . . . . 348 327

Price's Cut Leaf Acala, . . . . . . . . . . . . . . . . 89.1 94.7 88.9 90.9 . . . . . . . LM—— SLM-f- SLM SLM . . .. . 32 30 29 30 . . . . . 59 216 216 164

Kubela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 97.4 95.4 96.4 . . . . . . . . . . . . . . LM-l- LM . . . . . . . . . . 30 30 30 . . . . . . . . . . 244 360 302

Mebane 14_0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.4 94.2 94.8 . . . . . . . . . . . . . . SLM-l- . . . . . . . . . . 28 26 27 . . . . . . . . . . 278 374 326

New Boykln . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.8 94.8 95.3 . . . . . . . . . . . . . . SLM+ SLM SLM+ . . . . . . . . . . 30 28 29 . . . . . . . . . . 198 276 237

Cut Leaf x Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.2 92.2 . . . . . . . . . . . . . . . . . . . . . LM SLM . . . . . . . . . . . . . . . 30 30 . . . . . . . . . . . . . . . 263 263

Cut Leaf x Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.0 92.0 . . . . . . . . . . . . . . . . . . . . . SLM SLM . . . . . . . . . . . . . . . 29 29 . . . . . . . . . . . . . . . 254 254

Delta and Plne Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 .0 93 .0 . . . . . . . . . . . . . . . . . . . . . SLM SLM . . . . . . . . . . . . . . . 29 29 . . . . . . . . . . . . . . . 388 388

K1nsler's Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97.3 97.3 . . . . . . . . . . . . . . . . . . . .. SLM-i- SLM+ . . . . . . . . . . . . . . . 28 28 . . . . . . . . . . . . . .. 360 360

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.4 92.4 . . . . . . . . . . . . . . . . . . . .. LM SLM . . . . . . . . . . . . . . . 28 28 . . . . . . . . . . . . . . . 371 371

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 89.1 89.1 . . . . . . . . . . . . . . . . . . . . . LM SLM . . . . . . . . . . . . . . . 29 29 . . . . . . . . . . . . . . . 289 289

Lightning Express x Westex. . .. . . . . . . . . . . . . . . . . . . . 94.9 94.9 . . . . . . . . . . . . . . . . . . . . . SLM+ SLM+ . . . . . . . . . . . . . . . 29 29 . . . . . . . . . . . . . . . 408 408

Average . . . . . . . . . . . . . . . . . . 87.8 90.4 95.7 93 .8 92 1 LM LM—— SLM-F SLM SLM-l" 29 31 29 28 29 285 87 225 322 282

81 NOLLOO .210 SNLLSEIAHVH TVOINVHOEIW

VI

Table 2. Varieties of cotton tested for machine eﬂiciency, grade, staple, and acre yield at Lubbock

 

Percentage of machine _ _ Acre yield of lint
_ efﬁciency of the Grade Staple 1n 32nd inches pounds
Variety Texas Station Harvester
1936 1937 1938 Av. 1936 1937 1938 Av. 1936 1937 1938 Av. 1936 1937 1938 Av.
Ducona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97.4 . . . . . . . . 98.1 97.8 LMsp’ . . . . . . . . M+ SLMsp 31 450

Mebane 140 . . . . . . . . . . . . . . . . . . . . . . . . . . 98.3 . . . . . . . . . . . . . . . . 98.3 SLMsp . . . . . . . . . . . . . . . . SLMsp 30 559

Mebane 804 . . . . . . . . . . . . . . . . . . . . . . . . .. 97.7 . . . . . . .. 97.8 97 .8 SLM . . . . . . .. SM M 30 432

Cut Leaf x Acala. . . . . . . . . . . . . . . . . . . . .. 97.8 99.1 97.4 98.1 SLM M . M+ 32 480

Burnett . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.8 98.6 96.5 96.6 SLMsp M+ SM M+ 31

Kubela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.5 99 .0 96 .0 97.8 LM M 32 461

Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 98.7 . . . . . . .. 98.7 . . . . . . .. M+ . . . . . . .. M+ 30 641

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 97.6 . . . . . . .. 97.6 . . . . . . .. M . . . . . . .. M 29 535

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 99.2 . . . . . . .. 99.2 . . . . . . .. SM . . . . . . .. SM 30 666

Lightning Express x Westex. . . . . . . .. . . . . . . . . . . . 99.1 98.1 98.6 . . . . . . . . SLM SM 31 426

Cut Leaf x Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 97.6 . . . . . . .. 97 6 . . . . . . .. SLM+ . . . . . . .. SLM+ 32 491

Macha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.9 98.9 . . . . . . . . . . . . . . . . SM 30 296

Acala. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.7 98.7 . . . . . . . . . . . . . . . . SM SM 32 545

Ferguson 406 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 98.8 98.8 . . . . . . . . . . . . . . .. SM SM 29 299
Average ...................... .. 91.4 98.6 97.8 l 98.2 l SLMspi M+l SM l M+l a2 l a1 l . so 431

 

*SP—Spotted condition of the lint.

3
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NOLLVJLS LNEIIAIIHEIJXEI TVHHLTHOIHDV SVXELL ‘O89 'ON NLLEITIIIH

 

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MECHANICAL HARVESTING OF COTTON 15

Figure 7. View of part of the ﬁeld of varieties of cotton before harvesting with the
Texas Station‘ Harvester at Lubbock in 1938.

culty in removing the open cotton. Figure 9 shows how cotton is lost
when long limbs are present. A contrast is seen in Figure 1O where
the plant had short limbs and clusters of bolls.

Number of branches: A number of short, short-noded branches are
more desirable than a few long branches with the bolls spaced several
inches apart. One or two long branches that start near the base of
the plant can cause the loss of more cotton with the stripper harvester
than twice as many short branches uniformly spaced over the plant.
Figures 9 and 10 show comparatively the inﬂuence of long and short
branches on cotton losses.

Density of foliage: A dense foliage (Fig. 11) with great numbers
of large stems hinders the operation of mechanical strippers and pickers
by folding over the cotton and bolls. Dense foliage shades the bolls,
delays their opening, reduces the degree of boll spread, and during
damp weather may cause weak bolls and loss of cotton by rotting of
bolls. Brown (2) states that the leaf blades of most species are rather
thin and papery, but that some are thick and leathery. Efforts are
being made to reduce the density of foliage on varieties for mechanical
harvesting by adapting varieties with leaves of a deep-lobed or cut-leaf
type (Fig. 12).

16 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Figure 8. Field of cotton plants at Lubbock after harvesting with the Texas Station
Harvester and before the cotton lost by the harvester had been collected,
November 1938.

Figure 9. Showing how long branches Figure 10. The cotton from plants with
cause the loss of cotton by folding no long vegetative limbs is all re-
around the bolls when harvested with moved by the Texas Station Harvester.

the Texas Station Harvester.

MECHANICAL HARVESTING OF COTTON 17

Type 0f boll: Large bolls are more suitable than small bolls for both
mechanical stripping and picking. In stripping, the large bolls are usu-
ally stronger, more easily snapped off, and are more readily thrown from
the stripping units into the conveyor trough than small bolls. Cotton in
large bolls expands-and ﬂuffs out so the picker units can get hold of the
cotton and remove it from the boll.

Single bolls versus clusters of bolls: Bolls borne singly are more
satisfactory for all methods of harvest than two or more bolls attached
to the same peduncle or boll stem. When a cluster of bolls opens, the
carpels may overlap and even make picking by hand difficult. The peduncle
or boll stem is larger where the bolls are borne in clusters than for single

 

A ~ B C, 

Figure 11. Dense foliage causes more green leaves to be removed when the cotton is
harvested with machines. The cotton from rows B and C has been
harvested by the Texas Station Harvester, while the cotton from rows
A and D has not been harvested. Rows 'A and B are Gorham’s Lone
Star, and rows C and D are Ducona cotton. Note the amount of foliage
left on the plants by the machine.

bolls, and this makes it harder to remove a cluster of bolls from the
plant. A cluster of bolls will not readily pass through the extractor
because of its size. Mechanical cotton pickers do not harvest cotton
from bolls borne in clusters as efﬁciently as that from bolls borne singly,
because one or two picking units cannot handle the amount of cotton
concentrated in the cluster.

 

18 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Storm resistance: Cotton hanging loosely in the boll often falls out
as a result of the slightest jar to the plant. Gusts of Wind and hard
dashing rains may cause many locks to fall out on the ground. For
mechanical harvesting, the cotton should be held ﬁrmly in the boll but
should pull out fairly easily without leaving “tags” or one or two seeds
of the lock between adjacent parts of the boll. Long, strung-out,
dangling locks are often lost by the mechanical harvester, as the cotton
catches, hangs, and wraps around parts of the plant when an attempt

A is made to harvest it.

Flufﬁness of the cotton: Fluffiness of cotton is closely related to storm
resistance, as many cottons that expand and ﬂuff out of the boll are
easily shaken from the plant. Many ﬂuffy cottons, however, are rather

 

Figure 12. Three types of cotton leaves. The leaf on the left is a deep-lobed, cut-leaf,
okra type; the one on the right is a typical leaf found on most varieties;
' and the leaf in the center is an intermediate type. Less trash in harvesting
is collected from plants with smaller leaf areas.

storm resistant. Fluffiness is not an essential characteristic for mechan-
ical stripping but is necessary for mechanical pickers so that the picking
units can readily get hold of the ﬁber. In stripping, many of the fluffy
locks are likely to catch on parts of the plant and be lost.

Degree of boll spread: A widely opened boll permits cotton to ﬂuff
out more than does a boll that is not opened wide. Cotton is easier to
pick from widely spread bolls. Late maturing bolls that crack open
from one-eighth to one-fourth inch may be termed “smiley” bolls, as the

 

--_----—-u-mwwwnv 'wvwwm--n---~

MECHANXCAL HARVESTTNG OF COTTON 1g

white cotton showing between the carpel edges resembles a row of white
teeth when a person smiles.

Brittleness of branches and boll stems: In stripping cotton, the num-
ber of limbs removed depends, to-a large extent, on their brittleness and
the ease with which the peduncle or boll stem snaps. Table 10 shows
that the pounds of pull required to remove bolls and the number of limbs
pulled off with them vary with different varieties. The H. X. and Kel1y’s
Lone Star varieties were discarded because of the quantity of limbs
that broke off in harvesting.

Height of ﬁrst branches above ground: The pick-up ﬁngers of mechan-
ical harvesters can slip under low branches without digging into the soil
if the lowest branches are slightly above the ground. Seasonal condi-
tions, particularly in the northwestern part of the state, will affect the
height of the ﬁrst branches. Bolls on branches near the ground are
stripped from the plant by the pick-up ﬁngers and swept into the
machine by the plant. With mechanical pickers, the picking drums
cannot be adjusted low enough for picking units to remove the cotton
from bolls borne close to the ground. It is for this reason that the
mechanical picker cannot harvest the low cotton from plants grown
and left in lister furrows. The pick-up ﬁngers on the Texas Station
Harvester are so shaped that they will lift the low branches and remove
the cotton from plants grown either in listed furrows or on ridges.

Mechanical Factors

Pick-up ﬁngers: The ﬁrst part of a cotton harvester which touches
the cotton plant is the pick-up ﬁngers (Figs. 2 and 4). They should be
so shaped that they will slide under, lift up, guide, and fold the low
branches into the narrow passage between stripper rolls or picker drums.
They should be ﬂexible enough not to ride over cotton plants when the
machine gets slightly out of line with the row. It requires close atten-
tion and careful steering to keep a cotton harvester in perfect align-
ment with the row.

Stripping rolls: The size, length, type of surface, angle with ground,
ﬂexibility, tension, and peripheral speed of the rolls inﬂuence the effi-
ciency of a mechanical stripper. The effect of these factors is discussed
in detail in Station Bulletin 511, pages 11 to 19.

Stripper plate: Several devices were tried before a satisfactory method
was found to remove the cotton from the stripping rolls without consid-
erable loss of cotton. For smooth and knurled surface rolls, a one-inch
ﬂat steel bar set edgewise to the roll does excellent work. The bar is
set directly under the center of the roll close enough to prevent cotton
seed from passing between the bar and the roll. To prevent the stripper
rolls from drawing cotton under the plate, the cotton should be moved
away from the rolls as quickly as possible after it falls into the conveyor
trough.

20 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Rateof travel: Cotton must be harvested at a relatively slow rate
of travel to obtain the highest eﬁiciency. At fast speeds, it is difficult
to steer the tractor to keep the harvester in alignment with the row,
and the pick-up ﬁngers will hit the base of the plants with such force
that bolls will be shaken off. A fast speed will also cause the limbs to
be whipped around with such force that some bolls will be thrown off
and lost. It has been found in operating the Texas Station Harvester
that speeds ranging from 1% to 1% miles per hour give best results. The
effect of harvesting in low, second, and high tractor gears is discussed
in Station Bulletin 511, page 17.

Cultural Methods

To obtain the highest eﬂiciency with mechancal harvesters it is neces-
sary to practice cultural methods that will aid the performance of the
machine. Best results are obtained when a slight ridge is left along
the base of the plants. This sets the plants higher and makes them
more accessible to the harvesting units and facilitates the operation of
the pick-up ﬁngers. Less trash from the ground is collected by the pick-
up ﬁngers when they are run close to the ground, as winds shift dead
leaves and other loose trash into the protected depressions between the
rows. Straight, uniformly-spaced rows give better machine performance
than crooked and sharply curving rows.

Spacing of plants: Plants left unthinned increase the amount of
foliage and the number of stalks, which have somewhat the same effect
as long limbs. The bolls are folded in between plants, thus hindering
their removal. Spacing of 9 to 12 inches is satisfactory, while plants
spaced widely apart often grow too large and usually have several long
limbs.

EFFECT OF DIFFERENT HARVESTING METHODS ON THE
' QUALITY OF COTTON

Two general methods of harvesting cotton are practiced in Texas—
hand-picking in the central, southern and eastern areas and hand-snap-
ning in the northwestern part.

The picking of cotton by hand often is done carelessly and much trash
in the form of dead leaves, bract trash, and parts of burs is collected with
the cotton. Trashy hand-picked cotton is run through cleaning machinery
at the gin but, even so, not all of the trash is removed and lower grades
are the result.

Hand-snapping is the practice of pulling individual bolls by hand. This
selected method of snapping is used during the early season and until a
killing frost occurs. In snapping cotton only those bolls that are fully
matured and open should be harvested. Snapped cotton should not be
tramped in the wagon because the trash becomes more intermingled with
the ﬁber and makes it harder to remove. After frost when the leaves
are dead and the bolls are open or dry, all the cotton is removed from the

MECHANICAL HARVESTING OF COTTON 2i

plant in one operation——i. e., the hands are placed on each side of the
plant near the base and moved upward t0 the top, removing all bolls and
cotton. This method is termed “pulling cotton.” Where the plants are
fairly large and branching, pulling is impractical and the cotton is
snapped, one or two bolls at a time.

Of course, much trash is collected with the cotton in either snapping
or pulling, and the cottongtrade has tried to discourage these methods
of harvesting, with meager or no response. In fact, the practice of
snapping is spreading. Reports in 1938 indicated that some hand-snap-
ing was done in the extreme southern part of the State.

Hand-picked and hand-snapped cotton: Because of the widespread prac-
tice of snapping, samples of hand-picked and hand-snapped cotton were
collected in 1938 from several varieties of short, medium, and long staple
cottons at Lubbock, Spur, and Chillicothe to compare grade, staple, and
character as inﬂuenced by methods of harvesting. The snapped cotton
was run through the Station Bur Extractor to remove the burs and as
much trash as possible. Both the hand-picked and hand-snapped cottons
were cleaned with the Station Cylinder Cleaner and all samples ginned
on a 20-saw gin. Table 3 shows that all samples from the three loca-
tions classed strict middling, regardless of the method of harvesting.
The greatest difference was in the staple length and character of the
cotton.

At Lubbock- two of the six varieties showed longer staple for hand-
snapped than hand-picked cotton, while only one was longer for the
picked cotton. The other three varieties showed the same length for the
two methods of harvest. At Spur longer staple was obtained for hand-
snapped Bryant’s Mebane, while Missdel classed longer for the hand-
picked cotton. Four varieties were of equal length for the two methods
of harvest. Two varieties at Chillicothe showed longer staple for hand-
picked cotton. Other varieties were the same length. These differences
in length of staple are probably due to environmental conditions in the
ﬁeld (perhaps to soil moisture) and not to the method of harvesting.
The hand-picked cotton was run through a cleaner only, while the
snapped cotton was run through both an extractor and a cleaner.

Cotton from Spur had shorter staple and poorer character than cotton
from Lubbock or Chillicothe. This probably can be attributed to differ-
ences in weather conditions; therefore, different conditions give different
results and the data given for one year should not be taken as conclusive.

Hand-picked, hand-snapped, and machine-harvested cotton: Tables 4 and
5 show a comparison of grades obtained when cotton was harvested by
hand-picking, hand-snapping, and machine-harvesting (stripping). Table 4
shows that for 1938 at College Station for all varieties tested the hand-
picked cotton averaged middling plus; hand-snapped, middling; and ma-
chine-harvested, strict loW middling minus. There was a half grade dif-
ference in hand-picked and hand-snapped cotton and one and one-half
grades difference in hand-picked and machine-harvested cotton.

Table 3. Comparison of hand-picked and hand-snapped cotton at Lubbock, Spur, and Chillicothe for 1938
Lubbock Spur Chillicothe
Variety CLaracter Per cent Character Per cent Character Per cent
Length of Length of ' _ Length _of _
Grade staple in Clean Lint Grade staple in Clean Lmt Grade staple 1n _ Clean Llnﬁ
32nd inches Body Uni- seed turn- 32nd inches Body Uni- seed turn- 32nd mches Body Unr- seed turn-
formity cotton out formity cotton out formxty cotton out
Hand-picked
Mebane . . . . . . . . . . . . . SM 31 good good 98 .4 37 .2 SM 20 weak wasty 97. 9 41 .7 SM 30 weak good 98 . 1 38. 0

Half and Half . . . . . . . . SM 28 weak wasty 97.6 44.0 SM 26 weak wasty 97.2 34.8 SM 26 weak good 97.9 43.0

Stoneville. . _. . . . . . . . . SM 32 good good 97.3 34.2 SM 26 weak wasty 97.8 33.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Delta and Plne Land. SM 32 good good 97.3 37.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mebane 141. . . . . . . . . SM 31 good good 97.8 36.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Harley Speclal. .. . . . . SM 32 good good 98.0 34.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

lssdel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 29 weak wasty 97.2 29.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Boykin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 26 weak wasty 97.9 35 .5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mebane (Bryant's). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 26 weak wasty 97.4 38.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Watson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 28 weak wasty 98.2 37.5 SM 30 weak good 98.1 37.0

Mebane 140 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. SM 29 weak good 98.9 38.6

Acala 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. SM 33 good good 98.4 37.4

Roger's Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 32 weak good 97.9 36.1
Hand-snapped
M ebane . . . . . . . . . . . . . SM 32 good good 69 .1 37 .2 SM 20 weak wasty 69 .3 42 .3 SM 29 weak good 70 . 9 38 . 4

Half and Half . . . . . . . . SM 30 weak good 72.1 44.2 SM 26 weak wasty 68.5 34 .3 SM 26 weak wasty 75 .0 43 .0

Stoneville . . . . . . . . . . . SM 32 weak good 70.7 34.2 SM 26 weak wasty 67.0 35.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Delta and Pine Land. SM 32 good good 70.7 37.9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mebane 1_. . . . . . . . . SM 30 weak good 70.4 36.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Harley Speclal . . . . . . . SM 32 good good 68.4 33.9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

MISSdOl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 28 weak good 65.1 29. 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Boykin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 26 weak wasty 69.4 35.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mebane (Bryant’s).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 28 go good 66.5 39.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Watson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 28 weak good 69 .1 36.7 SM 30 weak good 73 .0 36.6

Mebane 140 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 29 weak good 76.7 38.1

Acala 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM 32 weak good 71.4 36.6

Roger's Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. SM 32 weak good 70.9 36.0

ZZ

NOLLVLS LNEIWIHHJXH TVHHLTIIOIHDV SVXELL ‘O89 ‘ON NI-LEFYIIIH

 

 

Table 4. Grade of varieties of cotton when hand-picked, hand-snapped, and machine-harvested at College Station*

Hand-picked Machine-harvested Differences
‘ between

_ Hand- hand-picked

Variety sna ped and machine-
1935 1936 1937 1938 Average 1538 1935 1936 1937 1938 Average harvested
cotton
Ducona . . . . . . . . . . . . . . . SLM SLM M M + SLM + SLM LM SGO SLNI LM LM 1%

Gorham’s Lone Star. . . . . . . . . . . 1\/Isp1‘ M + SM M + M —}— LM SLM SLM + SLM SLM 1%

Kelly’s Lone Star . . . . . . . . . . . . . . SLM SM . . . . . . . . M . . . . . . . . LM + LM SLM + . . . . . . . . SLM— 1%

H. X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LM . . . . . . . . . . . . . . . . . . . . . . . . LM . . . . . . . . . . . .

Rothcamp’s Cluster... . . . . . . . . . SLM . . . . . . . . . . . . . . . . SLM . . . . . . . . LM SGO . . . . . . . . . . . . . . . . SGO + 1%

Roger’s Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L1VI—— . . . . . . . . . . . . . . . . . . . . . . . . LM-—— . . . . . . . . . . . .

Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M + M + LM— . . . . . . . . . . . . . . . . SLM LM + 2

Pr1ce’s Cut Leaf Acala. . . . . . . . . . . . . . . . . . M M + M SLM + . . . . . . . . LM— SLM + SLM SLM— 1%

Kubela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M + M + M + . . . . . . . . . . . . . . . . LM LM + LM 2 %

Mebane140........... . . . . . . . . . . . . . . .. M+ SM SM— M . . . . . . . . . . . . . . .. + SLM+ M %

New Boykin . . . . . . . . . . . . . . . . . . . . . . . . . . M + SM SM—— . . . . . . . . . . . . . . . . SLM + SL SLM 1%

Cut Leaf x Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M + M + SLM + . . . . . . . . . . . . . . . . . . . . . . . . SLM SLM 1%

Cut Leaf x _Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M + M + SLM + . . . . . . . . . . . . . . . . . . . . . . . . SLM SLM 1%

Delta and Pine Land. . . . . . . . . . . . . . . . . . . . . . . . . . . SM SM . . . . . . . . . . . . . . . . . . . . . . . . SLM SLM 2

Kinslefs Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM SM SLM + . . . . . . . . . . . . . . . . . . . . . . . . SLM + SLM + 1%

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM SM M + . . . . . . . . . . . . . . . . . . . . . . . . SLM + SLM + 1%

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM SM M . . . . . . . . . . . . . . . . . . . . . . . . SLM SLM 2
Lightning Express x
Westex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M + M + M + . . . . . . . . . . . . . . . . . . . . . . . . SLM + SLM + 1
Average . . . . . . SLM ‘ SLM l M + SM M + M LM LM— SLM + SLM SLM 1 %
*The nine official American grades of cotton are designated as follows:

1. Middling fair _(MF).

2. Strict good middli (SGM).

3. Good middling (G ).

4. Strict middling (SM).

5. Middling (M). _

6. Strict low middlirﬁ (SLM).

7. Low middling (_L ).

8. Strict good ordinary (SGO).

9. Good ordinary (GO). _

TSP.—-—Sp0tted condition of the lint.
l

83 NOIIALOO e10 DNLLSEIAHVH "IVOINVHOHIAI

7K

Table 5. Grades of varieties of cotton when hand-picked, hand-snapped, and machine-harvested at Lubbock

Differences
Hand-picked Hand-snapped Machine-harvested between
hand-sna ped
Variety alllld mac 151e-
arveste
1936 1937 1938 Average 1937 1938 Average 1936 1937 1938 Average cotton

Diicona . . . . . . . . . . . . . . . Msp* . . . . . . . . SM M + . . . . . . . . SM SM LMsp . . . . . . . . M + SLMsp 3

Mebane 140 . . . . . . . . . . . M + . . . . . . . . . . . . . . . . M + . . . . . . . . . . . . . . . . . . . . . . . . SLMsp . . . . . . . . . . . . . . . . SLMsp . . . . . . . . . . . .
Mebane 804 . . . . .  . . . . M + . . . . . . . . SM SM— . . . . . . . . GM GM SLM . . . . . . . . SM M 2

Cut Leaf x Acala. . . . . M GM GM SM + M + SM SM— SLM M M + M %
Burnett . . . . . . . . . . . . . . . M GM SM A SM SM SM SM SLMsp M + SM M 1

Kubela . . . . . . . . . . . . . . . M SM SM SM— M + SM SM— SL M M + M %

Clark (late) . . . . . . . . . . . . . . . . . . . SM . . . . . . . . SM SM . . . . . . . . SM . . . . . . . . M + . . . . . . . . M +

Mebane 95 . . . . . . . . . . . . . . . . . . . . SM . . . . . . . . SM SM . . . . . . . . SM . . . . . . . . M . . . . . . . . M 1

Mebane 96 . . . . . . . . . . . . . . . . . . . . SM . . . . . . . . SM SM . . . . . . . . SM . . . . . . . . SM . . . . . . . . SM 0
Lightning Express x
Westex . . . . . . . . . . . . . . . . . . . GM SM SM + M + SM SM— . . . . . . . . SLM SM M %

Cut Leaf x Clark . . . . . . . . . . . . . GM . . . . . . . . GM SM . . . . . . . . SM . . . . . . . . SLM + . . . . . . . . SLM + 1 V,

Macha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SM SM . . . . . . . . SM SM . . . . . . . . . . . . . . . . SM SM O

Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. SM SM . . . . . . .. M + M + . . . . . . . . r . . . . . .. SM SM + %

Ferguson 406 . . . . . . . . . . . . . . . . . . . . . . . . . . SM SM . . . . . . . . SM SM . . . . . . . . . . . . . . . . SM SM 0

Average . . . . . . M SM + SM SM SM SM SM SLMsp M SM M %

*SP—Spotted condition of the lint.

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Table 6. Staple length, in thirty-seconds of an inch, of varieties of cotton when hand-picked, hand-snapped, and machine-harvested
at College Station

 

Hand-picked Machine-harvested
_ Hand-
Variety __ snapped
1938
1935 1936 1937 1938 Average 1935 1936 1937 1938 Average
Ducona . . . . . . . . . . . . . . '. . . . . . . . . . . . . 31 34 32 32 32 31

G0rham’s Lone Star . . . . . . . . . . . . . . . . _ _ . . . . . . 32 29 3O 3O 31

Kelly’s Lone Star . . . . . . . . . . . . . . . . . . _ _ . . . . . . 32 3O . . . . . . .. 31 3O

H. X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

R0thcamp’s Cluster . . . . . . . . . . . . . . . . _ _ . . . . . . 32 . . . . . . . . . . . . . 32 31

R0ger’s Cluster . . . . . . . . . . . . . . . . . . . . _ _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3O

Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3O

Price’s Cut Leaf Acala . . . . . . . . . . . . . _ , . . . . .. 32 30 30 31 30

Kubela . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ _ . . . . . . . . . . . . . . 3O 31 3O 3O

Mebane140.......................__............., 31 . . . . . . .. 31 28_

New Boykin . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . 28 29 28 29

Cut Leaf x Acala . . . . . . . . . . . . . . . . . . , _ . . . . . . . . . . . . . . . . . . . . .. 30 3O 3O

Cut Leaf x Clark . . _ . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . .. 3O 3O 29

Delta and Pine Land . . . . . . . . . . . . . . _ _ . . . . . . . . . . . . . . . . . . . . .. 3O 30 29

Kinslefs Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29 29 28

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 28 28

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 29 29

Lightning Express x Westex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 30 29

Average . . . . . . . . . . . . . . . . . .. 31.0 32.4 30.0 29.8 30.0 29.5

 

98 NOLLOO JO ‘DNLLSEIAHVH TVOINVHOHW

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Table 7. Staple length, in thirty-seconds of an inch, of varieties of cotton when hand-picked, hand-snapped, and machine-harvested at Lubbock z
' O

Hand-picked Hand-snapped Machine-harvested g

Variety ‘F?

1936 1937 1938 Average 1937 ' 1938 Average 1936 1937 1938 Average >4

5

Ducona . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 . . . . . . . . 30 32 . . . . . . . . 28 28 33 . . . . . . . . 30 31 E

Mebane 140 . . . . . . . . . . . . . . . . . . . . . . . 31 . . . . . . . . . . . . . . . . 31 . . . . . . . . . . . . . . . . . . . . . . . . "30 . . . . . . . . . . . . . . . . 30 5U

Mebane 804 . . . . . . . . . . . . . . . . . . . . . . . 32 . . . . . . . . 3O 31 . . . . . . . . 30 30 31 . . . . . . . . 30 30 8

Cut Leaf x Acala . . . . . . . . . . . . . . . . .. 34 31 29 31 31 32 31 33 32 31 32 C;

Burnett . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 28 29 30 30 30 30 31 31 29 30 r‘

Kubela . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 31 32 32 31 31 31 32 32 31 32 H

Clark (late) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 . . . . . . . . 29 30 . . . . . . . . 30 . . . . . . . . 30 . . . . . . . . 30 C!

Mebane 9s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2s . . . . . . .. 2s 29 . . . . . . .. 29 . . . . . . .. 29 . . . . . . .. 29 P“

Mebane 9e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2s . . . . . . .. 2s 30 . . . . . . .. 30 . . . . . . .. 30 . . . . . . .. 30 g

Lightnin Express x Westex . . . . . . . . . . . . . . .. 32 30 31 30 32 31 . . . . . . .. 32 3O 31

Cut Lea x Clark . . . . . . . . . . . . . . . . . . . . . . . . .. 31 . . . . . . .. 31 31 . . . . . . .. 31 . . . . . . .. 32 . . . . . . .. 32 b1

Macha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 29 . . . . . . . . 3O 30 . . . . . . . . . . . . . . . . 3O 30 >4

Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 33 . . . . . . . . 32 32 . . . . . . . . . . . . . . . . 32 32 g

Ferguson 406 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 29 . . . . . . . . 30 3O . . . . . . . . . . . . . . . . 29 29 w
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Average . . . . . . . . . . . . . . . . . .. 32.7‘ 29s‘ 30.1‘ 30.4‘ 30.2 ‘ 30.6‘ 30.2 ‘ 31.7‘ 31.0‘ 30.2‘ 30.6 E
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MECHANICAL HARVESTING OF COTTON 27

Comparison of data for two years at Lubbock showed a slight differ-
ence in favor of hand-picked over hand-snapped cotton (Table 5). Both
averaged strict middling for the two years. ~In 1937 machine-harvested
cotton averaged one grade lower than hand-snapped cotton, but in 1938
the average for the three methods of harvesting was strict middling.

Tables 6 and 7 show a comparison of staple length for the three methods
of harvest at College Station and Lubbock. The hand-picked cotton at
College Station in 1938 averaged approximately one sixty-fourth inch
longer than hand-snapped or machine-harvested cotton (Table 6). For
the same year at Lubbock the hand-snapped cotton was slightly longer
than cotton harvested by the other two methods (Table 7). In 1937, how-
ever, machine-harvested cotton at Lubbock averaged about one thirty-
second inch longer than cotton picked or snapped. The data shown in
Tables 6 and 7 do not indicate that machine harvesting and extracting
affect the staple of the cotton to any appreciable extent. The slight
variations in staple length that occur are no doubt due largely to environ-
mental conditions in the ﬁeld rather than to methods of harvesting.

EXTRACTING QUALITIES OF VARIETIES

In these studies on extracting cotton the harvested cotton was con-
veyed directly to the extractor, which was mounted on the drawbar of
the tractor; and the burs, green bolls, and as much of the green-leaf and
other trash as possible were removed before the cotton was conveyed to
the trailer (Fig. 1).

The function of an extractor, as used in the ﬁeld in combination with
a cotton harvester of the stripper type, is the removal of burs, green,
unopened bolls, either mature or immature, dry hard bolls resulting from
insect injury, sticks, rocks, sections of limbs, leaf stems, and leaf sections
of various sizes.

Factors affecting the efficiency of extracting equipment used in combina-
tion with harvesting equipment may be classed as varietal characteristics
and mechanical and other factors.

Varietal Characteristics

The varietal characteristics affecting the eﬁiciency of an extractor are:
(1) feeding rate or rate of inflow of material as affected by yield;
(2) amount of burs, unopened bolls, limbs, sticks, stems, and leaves
mixed with cotton; (3) size of boll; (4) shape of boll; (5) weight of burs;
(6) degree of boll spread (how wide the boll carpels spread apart when
the boll is completely open); (7) ﬁufﬁness or protrusion of cotton from
the boll; (8) degree of storm resistance (how hard the cotton is to re-
move from the boll); and (9) interlocking pull of ﬁbers between seeds.

Rate of feeding: When the harvester and extractor are in operation,
the cotton fed into the extractor varies as the yield varies along the
row and as the rate of travel varies. These factors were found to
affect the efficiency of the extractor.

wide enough.

28 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Amount ofburs and trash in cotton: The ratio of cotton to the amount
of burs, unopened bolls, limbs, sticks, stems, and leaves has a direct bear-
ing on the efﬁciency of the extractor and the cleanliness of the extracted
cotton. A large amount of foreign material will prevent the cotton from
touching the saw teeth readily and more limbs, stems, and sections of
leaves will be caught by the saws and thrown out with the cotton.

Size of bolls: Minor adjustments on the extractor enable it to extract
equally well from either small or large bolls, provided they are open
Small burs will ﬂow through the extractor faster than
large ones, because they pass between the ﬁngers more readily. Large
burs remaining on the ﬁngers after the cotton has been extracted enlarges
the volume of material, reduces efficiency, and increases the amount of
boll shale, as the burs will be repeatedly thrown against the extractor
saw teeth and chips cut out and mixed with the cotton.

Shape of boll: It appears that cotton can be extracted from round,
blunt-pointed bolls better than from tapering, pointed bolls, as it is
more likely to be fluffed out beyond the ends of the bur carpels. Thin,
weak bolls are often crushed by the stripping rolls of the harvester as
they are pulled from the plant. As a rule, single carpels are easier to
separate from the cotton than whole burs. These carpels, however, some-
times get by the bur doffer and pass out with the cotton. Whole burs
cannot get by the doffer and must pass downward between the ﬁngers
of the extractor. Bolls are seldom crushed by the extractor, and strong
bolls are not crushed as badly in harvesting as weak bolls.

Weight of burs: The size of the bolls and the thickness of the bur
determine, to a large extent, the weight and percentage of trash removed
by the extractor, as shown in Tables 8 and ,9, for varieties harvested
at College Station and Lubbock. At both locations harvesting the Du-
cona variety, which has medium-sized bolls with thick burs, showed that
approximately 35 per cent of the total material harvested was trash
removed by the extractor. At College Station for the same period Gor-
ham’s Lone Star, which is a big boll cotton, averaged 30.7 per cent trash
(Table 8). Several other varieties were lower for one-year periods.
Table 9 shows that the Lightning Express x Westex cross, having a
medium-sized boll with thin burs, averaged 25.4 per cent burs and trash
removed by the extractor. The average removed by the cleaner for this
variety was 5.9 per cent, leaving an average of 68.7 per cent clean seed
cotton, which is 5 per cent above the general average of all varieties.

For all varieties at both College Station and Lubbock a general average g

of approximately 31 per cent of the total material harvested was re-
moved by the extractor (Tables 8 and 9).

Degree of boll spread: The wider a boll is spread open the easier it
is for the extractor saws to catch and remove the cotton. Figure 17
shows how the degree of boll spread was measured. The spread varies
from year to year, with the season and the variety, as shown in Tables
13 and 14. Such conditions may affect the efficiency of the extractor.

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Table 8. The percentage of trash removed from diﬂerent varieties of cotton by the Texas Station Extractor and the Cylinder Cleaner at
College Station

 

V _ t Extractor Cylinder Cleaner Percentage of Seed Cotton remaining

arle y —-i——-———————
1935 1936 1937 1938 Average 1935 1936 1937 1938 Average 1935 1936 1937 1938 Average

Ducona . . . . . . . . . . . . . . . . . . . . . .. 35.2 9.0 6.4 6.3 10.0 7.9 59.7 57.0 54.3 56.5 56.9

Gorham's Lone Star . . . . . . . . . . .. 30.7 10.7 4.9 8.1 11.1 8.7 62.4 59.1 60.0 60.8 60.6

Kelly's Lone Star . . . . . . . . . . . . .. 27.5 7.0 4.1 6.8 . . . . . . .. 6.0 74.7 61.1 63.2 . . . . . . .. 66.3

H. X . . . . . . . . . . . . . . . . . . . . . . . . .. 27.7 8.8 . . . . . . . . . . . . . . . . . . . . . . . .. 8.8 63.5 . . . . . . . . . . . . . . . . . . . . . . .. 63.5

Rothcamp’s Cluster . . . . . . . . . . .. 29.9 8.7 10 2 . . . . . . . . . . . . . . .. 9.5 69.0 52 1 . . . . . . . . . . . . . . .. 60.5

Roger's Cluster . . . . . . . . . . . . . . .. 27.8 6.4 . . . . . . . . . . . . . . . . . . . . . . .. 6.4 65.8 . . . . . . . . . . . . . . . . . . . . . . .. 65.8

Clark . . . . . . . . . . . . . . . . . . . . . . . .. .6 29.2 7.8 . . . . . . . . . . . . . . .. 6.9 7.1 65.9 . . . . . . . . . . . . . . .. 61.5 63.7

Price's Cut Leaf Acala . . . . . . . .. .5 32.4 . . . . . . .. 5.5 4.7 8.6 6.2 . . . . . . . . 59.2 64.7 59.9 61.3

Kubela . . . . . . . . . . . . . . . . . . . . . . .. .0 32.3 . . . . . . . . . . . . . . .. 5.5 7.9 6.7 . . . . . . . . . . . . . . .. 60.8 61.1 61.0

Mebane 140 . . . . . . . . . . . . . . . . . .. .1 30.5 . . . . . . . . . . . . . . .. 4.2 8.1 6.1 . . . . . . . . . . . . . . .. 65.9 60.8 63.4

New Boykin . . . . . . . . . . . . . . . . . .. .8 31.2 . . . . . . . . . . . . . . .. 7.1 9.7 8.4 . . . . . . . . . . . . . . .. 60.3 60.4 60.4

Cut LeafxAcala . . . . . . . . . . . . .. .4 31.4 . . . . . . . . . . . . . . . . . . . . . . .. 5.1 5.1 . . . . . . . . . . . . . . . . . . . . . . .. 63.5 63.5.

Cut Leafx Clark . . . . . . . . . . . . .. .0 31.0 . . . . . . . . . . . . . . . . . . . . . . .. 6.9 6.9 . . . . . . . . . . . . . . . . . . . . . . .. 62.0 62.0

Delta and Pine Land . . . . . . . . . .. .7 31.7 . . . . . . . . . . . . . . . . . . . . . . .. 8.1 8.1 . . . . . . . . . . . . . . . . . . . . . . .. 60.2 60.2

Kinslefs Cluster . . . . . . . . . . . . . .. .4 28.4 . . . . . . . . . . . . . . . . . . . . . . .. 10.5 10.5 . . . . . . . . . . . . . . . . . . . . . . .. 61.1 61.1

ebane 96 . . . . . . . . . . . . . . . . . . .. .5 35.5 . . . . . . . . . . . . . . . . . . . . . . .. 5.8 5.8 . . . . . . . . . . . . . . . . . . . . . . .. 58.7 58.7

Mebane 95 . . . . . . . . . . . . . . . . . . .. .4 33.4 . . . . . . . . . . . . . . . . . . . . . . .. 8.3 8.3 . . . . . . . . . . . . . . . . . . . . . . .. 58.3 58.3

Lightning Express x Westex. . .. .8 29.8 . . . . . . . . . . . . . . . . . . . . . . .. 8.0 8.0 . . . . . . . . . . . . . . . . . . . . . . .. 62.2 62.2
Average ............. .. 25.3 l 35.8 l 32.6 l 31.3 l 3o 9 l s3 l 6 2 l 61 l 3.2 1.5 65 9 57.7 613 60.5 61.6

6Z NOLLOO .110 SNLLSEIAHVH QVOINVHOIEIN

Table 9. The percentage of trash removed from diﬁerent varieties of cotton by the Texas Station Extractor and the Cylinder Cleaner at Lubbock

Extractor Cylinder Cleaner Percentage of Seed Cotton remaining
Variety
1936 1937 1938 Average 1936 1937 1938 Average 1936 1937 1938 Average
Mebane 804 . . . . . . . . . . . . . .. 30.3 . . . . . . .. 31.4 30.8 1.4 . . . . . . .. 4.0 2.7 68.4 . . . . . . .. 64.6 66.5

Burnett . . . . . . . . . . . . . . . . . .. 36.8 29.7 31.9 32.8 1.8 3.9 3.0 2.9 61.5 66.4 65.1 64.3

Mebane 140 . . . . . . . . . . . . . .. 36.9 . . . . . . . . . . . . . . .. 36.9 2.2 . . . . . . . . . . . . . . .. 2.2 60.9 . . . . . . . . . . . . . . .. 60.9

Cut Leaf x Acala . . . . . . . .. 32.1 28.8 28.4 29.8 1.9 6.2 5.0 4.3 66.0 65.0 66.6 65.9

Ducona . . . . . . . . . . . . . . . . . .. 40.0 . . . . . . .. 29.9 34.9 1.7 . . . . . . .. 3.9 2.8 58.3 . . . . . . .. 66.2 62.2

a . . . . . . . . . . . . . . . . . .. 24.7 30.6 29 8 28.4 2.3 7.5 6.7 5.5 73.0 61.9 63.5 66.1

Clark (late) . . . . . . . . . . . . . . . . . . . . . .. 31.6 . . . . . . .. 31.6 . . . . . . .. 7.9 . . . . . . .. 7.9 . . . . . . .. 60.6 . . . . . . .. 60.6

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . .. 31.0 . . . . . . .. 31.0 . . . . . . .. 8.9 . . . . . . .. 8.9 . . . . . . .. 60.0 . . . . . . .. 60.0

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . .. 36.5 . . . . . . .. 36.5 . . . . . . .. 3.8 . . . . . . .. 3.8 . . . . . . .. 49.7 . . . . . . .. 49.7

Lightnin ExgressxWestex. . . . . . . .. 26.4 24.4 25.4 . . . . . . .. 7.7 4.1 5.9 . . . . . . .. 65.9 71.5 68.7

Cut Lea x lark . . . . . . . . . . . . . . . .. 29.4 . . . . . . .. 29.4 . . . . . . .. 6.8 . . . . . . .. 6.8 . . . . . . .. 63.8 . . . . . . .. 63.8

Macha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26.5 26.5 . . . . . . . . . . . . . . .. 5.0 5.0 . . . . . . . . . . . . . . .. 68.5 68.5

Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29.6 29.6 . . . . . . . . . . . . . . .. 4.2 4.2 . . . . . . . . . . . . . . .. 66.2 66.2

Ferguson 406 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 27.9 27.9 . . . . . . . . . . . . . . .. 3.6 3.6 . . . . . . . . . . . . . . .. 68.5 68 5

Average . . . . . . . . .. 33.4 30.5 28.9 30 8 1.9 6 6 4.4 4.8 64 7 61.7 66.7 63 7

08

NOILVLS LNEIWIHEIJXEI TVHHLTIIOIHDV SVXHL ‘O89 "ON NLLEVITIIH

MECHANICAL HARVESTING OF COTTON 31

Fluffiness: Cotton that expands and ﬂuffs out beyond the boll carpels
enables the extractor saw teeth to engage the ﬁbers and pull the cotton
from the boll. On the other hand, it is difficult for the saw teeth to
catch and remove cotton not ﬂuffed out beyond the boll carpels.

Storm resistance: Open bolls that hold the cotton well during storms
or periods of windy weather are termed storm proof. The lower part of
each lock is held rather securely between adjacent parts of the bur.
Should the lock be held too ﬁrmly, it is hard for the extractor to remove
all of the cotton. One or two seeds may be left in the bur, and these
are usually termed “tags.” It is desirable to have sufﬁcient storm re-
sistance for the cotton to remain in the boll until harvested but pull from
the boll easily enough for good extraction. This is also an important
point in the use of the mechanical picker. The Macha cotton (Figs. 7
and 18) tested at Lubbock in 1938 is extremely storm resistant—so
much so that it is difficult to extract Without crushing the boll. A
number of ﬁbers of each lock are usually attached to the sides of
the bur carpels (Fig. 13). The ﬁber did not expand enough to project

 

Figure 13. Macha bolls on the left and a common cotton boll on the right. Note the
differences in the ﬁufﬁness and the ﬁbers hanging to the boll of the highly
storm resistant Macha bur, lower left.

32 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION
beyond the points of the carpels; consequently, some machining of the ﬁber
occurred in the extracting process.

Fiber drag between seed: Fiber drag is the resistance offered to the
separation of the seeds of a lock of cotton. It is not uncommon to see
a lock of cotton strung out and the seeds almost separated as they hang
in the boll, showing the lack of ﬁber drag between seeds. For good ex-
tracting there should be enough ﬁber drag between seeds of a lock. of
cotton to enable the coarse extractor saw teeth to catch ﬁrmly and pull
the cotton from the bur.

Tests indicated that the interlocking pull or drag of ﬁbers between
seeds of a lock of the Macha variety was as much as two pounds, while
in ordinary varieties the average pull did not exceed one-half pound. A
certain amount of inter-seed drag is essential in removing the cotton
from the boll for both the extractor and the mechanical picker. The
Lightning Express x Westex cross appears to be rather storm resistant
and has enough ﬁber drag between seeds for good mechanical extraction
and picking.

- Mechanical and Other Factors

Mechanical and other factors that affect the eﬁiciency of extracting
equipment are: (l) rate of travel along row, (2) rate of ﬂow of material
through machine, (3) speed of extractor saws, (4) compactness of mate-
rial presented to extractor saws, (5) uniformity of distribution of mate-
rial along extractor saws, and (6) agitation of material presented to
extractor saws.

Rate of travel: It is obvious that when the cotton harvester is trav-
eling along the row at 2 miles an hour more cotton will be fed into the
extractor than when traveling at 1i or 1% miles an hour, which is the
usual rate of travel. Consequently, when harvesting unusually heavy
yields, cotton may be fed into the extractor faster than the extractor
saws can remove the cotton from the burs. Such conditions result in
poor extracting, greater loss of cotton by the extractor, and more trash
being carried out with the extracted cotton. In order to prevent over-
loading the extractor in harvesting heavy yields of cotton, the harvester
must be operated at a rate of travel that will enable the extractor to
perform efﬁciently.

Rate of ﬂow: The rate of ﬂow of the material through the Texas

Station Extractor is controlled by adjusting either or both the stationary .

and oscillating ﬁngers closer to or farther away from the extractor saws -

and by the peripheral speed of the extractor saws. Adjusting the ﬁngers
away from the saws so that the burs will ﬂow easily between them and
the extractor saws will result in poor extracting and a greater loss of
cotton with the burs. On the other hand, if the ﬁngers are adjusted close
to the extractor saws, the burs will not ﬂow easily through the machine
and any large burs and clusters of burs will remain on the ﬁngers and
be presented to the saws again and again until torn up suﬂiciently to

MECHANICAL HARVESTING OF COTTON 33

pass through the spaces provided. Such a condition will cause the saws
to chip the burs and result in undesirable boll shale being mixed with
the extracted cotton.

Speed of extractor saws: The Texas Station Bur Extractor was de-
signed to handle cotton containing green leaves and green, unopened
bolls as well as mature open cotton. It is necessary, therefore, to oper-
ate it at a relatively slow rate of speed in order to avoid staining the
cotton and to permit the green, unopened bolls to pass between the ex-
tractor ﬁngers and the extractor saws without tearing them open. Crush-
ing of the burs, as is done in most factory-made extractors, is not prac-
ticed, because of the presence of green material in the cotton.

Compactness of material: The compactness of the material will de-
pend on both the rate of feeding and the rate of ﬂow of the material
through the machine and is comparable to the tightness of the gin-roll in
the cotton gin. Best results are obtained when the stripped cotton, burs,
and other trash are kept fairly loose. A tight, compact mass presses
the burs hard against the extractor saws and, as a result, the burs are
chipped; green, unopened bolls are ripped open; and pieces of limbs, leaf
stems, and large sections of leaves are caught by the saws and carried
through with the extracted cotton.

Distribution and agitation: Thorough distribution aids in preventing
one side of the extractor from becoming overloaded and the other side
from being left practically empty. Agitation is necessary to keep the
material in the “extractor roll” agitated so that empty burs, green bolls,
limbs, leaves, and other foreign trash can fall between the ﬁngers, and
burs with cotton‘ in them can be presented to the extractor saw teeth.
Thus, a loose mass permits more trash to pass between the ﬁngers, and
obviously the extracted cotton will be cleaner. Unlike the cotton gin,
the extractor roll should not be tight enough to depend entirely on the
extractor saw to keep it in motion. Consequently, this action is aided
by the setof oscillating ﬁngers, which are adjusted so that on the ‘for-
ward movement they pass slightly beyond the edges of the stationary
ﬁngers and strike the stripped cotton with enough force to cause it to
move. On the backward stroke the oscillating ﬁngers pass far enough
back of the stationary ﬁngers to leave an open space between the ends
of the ﬁngers and the extractor saws to permit whole burs, unopened
bolls, and other trash to pass through. Thus, these two sets of ﬁngers
serve a threefold function—namely, they adjust the ﬂow of material, reg-
ulate the tightness of the extractor roll, and agitate the roll.

CLEANING QUALITIES OF VARIETIES

Varietal Characteristics

Cleaning is the third process in handling cotton mechanically stripped,
and it has much inﬂuence on the gin injury and grade of lint. The qual-

34 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

ity of work done by a cleaner is affected by several varietal characteristics

as follows: (1) amount and kind of trash, (2) density of ﬁber on seed, a

(3) kind of ﬁber (whether coarse or ﬁne), and (4) length of ﬁbers.

Amount and kind of trash: The amount and kind of trash inﬂuence
considerably the efﬁciency of a cleaner. Obviously, large amounts of
trash become more intermingled with the ﬁbers than small amounts and
are harder to remove. Dry-leaf trash is easily removed from cotton
having dense coarse ﬁbers not over one inch in length. Bract trash with
its many ﬁne curling points is hard to remove from any kind of cotton
but harder from the ﬁne, silky types. The development of a variety of
cotton devoid of bracts would eliminate this kind of trash and should
result in cleaner cotton.

Removing green-leaf trash from cotton is much'more difficult than
removing dry-leaf trash. The foliage of most cotton varieties is slightly
pubescent* and readily clings to cotton ﬁbers. The green-leaf trash re-
moved from the plant by mechanical harvesters may range in size from
sections one-half inch square or less to the whole leaf. When cotton is
harvested with the stripper-type Texas Station Harvester, many sections
and whole leaves are removed from the cotton as they pass over the
slotted bottom of the conveyor trough and more are removed by the ex-
tractor, but under full green foliage condition enough leaves remain in
the cotton to require a few hours of drying before the cotton can be
bulked safely. Mechanical picker-type harvesters also collect an objec-
tionable amount of green-leaf trash. One of the major problems of
mechanical harvesting of cotton, therefore, is the separation and removal
of green-leaf trash from the harvested cotton between the time it is
taken from the plant and before it reaches the storage bag or trailer.

In these experiments a number of devices and shapes of slots have
been installed and tested in the harvester conveyor troughs, and many
changes have been made in the extractor in an effort to remove the
green-leaf trash harvested with the cotton. These changes and improve-
ments have made it possible to remove a higher percentage of the green-
leaf trash than was removed in the earlier tests. The ultimate objective
in these experiments is to remove a sufficiently high percentage of green-
leaf trash so that the machine-harvested cotton may be carried directly
to the gin or bulked without danger of heating.

Density of ﬁber: In studying cleaning qualities of varieties included
inthese experiments, it was found that varieties having dense ﬁber sur-
rounding the seed clean better than those varieties with less dense ﬁbers.
The dense ﬁbers prevent particles of trash from becoming embedded or
entangled in them and, as a result, are more readily cleaned by adequate
cleaning machinery. Typical varieties which appear to have a dense
ﬁber characteristic are Gorham’s Lone Star, New Boykin, Mebane 140,
Mebane 804, Mebane 96, and Lightning Express x Westex. Mebane 95

*Pubescence is a hairy condition of the foliage.

MECHANICAL HARVESTING OF COTTON 35

has rather loose or sparse ﬁber adjacent to the seed. For comparison,
Tables 4 and 5 show that a higher grade was obtained and less trash
was removed by the cleaner from the dense-ﬁbered Mebane 96 than from
the sparse-ﬁbered Mebane 95, indicating that less trash was left em-
bedded and entangled with the denser ﬁber by the extractor.

Kind of ﬁber: Trash can be removed from coarse-bodied cotton much
more easily than from ﬁne, silky cotton. It is difﬁcult to say whether
silky ﬁbers adhere to the trash or whether the trash hangs and sticks
to the ﬁne, silky ﬁbers. Atany rate, the trash is hard to remove from
ﬁne- and soft-bodied cotton. Naturally the presence of excessive amounts
of trash in the lint will result in lower grades. The ﬁber of Ducona
cotton is rather ﬁne, and Table 1 shows that the grade for four years
at College Station averaged low middling, which is lower than for Gor-
ham’s Lone Star, a variety producing a heavy-bodied cotton ﬁber. Breed-
ing work is under way to obtain strains of Ducona cotton with a heavier
bodied ﬁber.

Length of staple: Varieties of cotton with a staple length of one inch
or more often have a tendency to wrap around trash particles and pre-
vent their removal. As the length of the staple increases above one inch,
there is a decided increase in the tendency for the staple to twist and
rope in the cleaning machinery.

Mechanical and Other Factors

Mechanical and other factors that affect the efficiency of cleaning equip-
ment are: (1) previous handling, (2) type of cleaner, (3) speed of re-
volving parts, (4) kind and condition of screens, (5) rate of feeding, and
(6) moisture content.

Previous handling: Bennett and Gerdes (1) state that rough handling
is responsible for intermingling with seed cotton parts of the cotton
plants, such as leaves, burs, and stems, and such foreign matter as
sticks, weeds, and trash. When the Texas Station Cotton Harvester, Ex-
tractor, and Cleaner were designed, an effort was made to construct and
use devices that would start removing trash immediately after the cot-
ton fell into the harvester conveyor. Some dirt, leaves, stems, limbs,
and parts of burs are removed before the cotton reaches the extractor.
The extractor removes practically all burs, unopened green and dry bolls,
and most of the remaining leaves, limbs, stems, sticks, and other trash.
The mechanism has not been perfected so that 100 per cent of all the
objectionable material is removed, as enough green-leaf trash remains
in the cotton to require a few hours of sun drying before it can be bulked
without heating (8). As the cleaner is a separate unit and not used in
the ﬁeld, it is necessary to place the cotton in a wagon or trailer and
transport it to the cleaner. This handling naturally causes much of
the trash to become intermingled with the seed cotton and, of course,
makes it more difﬁcult to remove.

36 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Type of cleaner: Cleaners used in connection with gins are classed as
air-line cleaners and out-of-air cleaners. The latter are strictly mechan-
ical cleaners with various types of beaters and screens. The Texas Sta-
tion Cylinder Cleaner used in cleaning the mechanically harvested cotton
is a mechanical cleaner employing several sets of ﬁnger beaters to throw
the cotton against one-half inch mesh hardware cloth. Beaters too close
to the screen may cause machining of the cotton and if too far away
may produce roping, twisting, or rolling of the cotton. _ The type of
cleaner, therefore, and its adjustment and action on the cotton will affect
its eﬂiciency in removing trash from the cotton. Figure 14 shows a
comparison of cleaned, extracted, and mechanically harvested cotton with
uncleaned, hand-picked cotton.

Speed of cleaner parts: The speed, or revolutions per minute, of
cleaner cylinders is a factor that affects the removal of trash and injury

Figure 14. Views showing uncleaned, machine-stripped cotton on the left and uncleaned,

hand-picked cotton on the right. The cotton in the center was machine-
harvested and cleaned ‘with the Texas Station Cylinder Cleaner. The Ducona
cotton in the upper picture does ont clean so well as the Gorham’s Lone Star
cotton below because of the ﬁner and more silky staple of this variety.

 

 hri-ﬂn “.1”; 1...“...

L

I

MECHANICAL HARVESTING OF COTTON ' i 37

to the seed, which may be cracked if hit too hard. The speed of most
cylinder cleaners ranges from 300 to 600 revolutions per" minute. Large
cylinders may revolve slower than small ones yet have approximately the
same peripheral speed at the ends of the heaters. In the Texas Cylinder
Cleaner, the beater cylinder is approximately 22 inches in diameter and
operates at about 500 revolutions per minute. It has been found that
faster speeds have a tendency to cause machining of the ﬁber and crack-
ing of some seeds. Fast speeds also increase the tendency of the ﬁbers
to twist and rope, especially in the longer staple cottons.

Feeding rate: The rate of feeding, or the volume of material passing
through a cleaner, materially affects trash removal. Best results are
obtained when cotton is fed at a rate that enables the beater arms to
spread the cotton in a thin layer over the screen, so that the trash is
jarred loose from the cotton as it hits the screen and passes through
while the cotton is retained on the screen. Large volumes of cotton
prevent such action and reduce the amount of trash removed.

Screens: Most cleaners are enclosed "with heavy, one-half inch mesh
hardware cloth, but one company makes use of expanded metal. Rough
or sharp edged material has a tendency to cause machining of the cotton.

Moisture content: If cotton is at all damp, it will not clean satisfac-
torily. Both the cotton and the trash must be thoroughly dry for eﬂicient
removal of the trash. Crumbly, dry-leaf trash can be readily separated
from coarse-ﬁbered cottons of not more than one inch in length. If
either the cotton or the trash is damp, they will cling together and are
hard to separate. Cotton in a damp condition will also twist and rope
when run through a cleaner.

FACTORS AFFECTING THE GRADE OF MECHANICALLY
HARVESTED COTTON

The grade of cotton harvested by machinery is aﬁected by varietal
characteristics and mechanical and other factors.

Varietal Characteristics

The varietal characteristics that affect the grade of mechanically har-
vested cotton are as follows: (1) amount of trash collected in the har-
vesting process, (2) kind of trash collected with the cotton, (3) ﬁneness
of the ﬁber, (4) density of the ﬁber on the seed, and (5) length of the
staple. Any one of these factors, if present, will inﬂuence more or less
the grade of mechanically harvested cotton. Some, however, are of
greater importance than others and will inﬂuence the grade regardless
of the method of harvest.

Amount and kind of trash in cotton:
amount and kind of trash are important.

With the mechanical stripper the
It is needless to point out that

38 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

large quantities of any kind of trash are harder to remove than small
amounts. The kind and nature of the trash are signiﬁcant, because
ﬁbrous material such as grass or bark from the cotton plant is very
hard to remove, while dry, crumbly leaf trash is comparatively easy to
remove from seed cotton. Bract trash, which has many pointed sections
that curl when dry and catch and hang to the cotton ﬁber, is extremely
hard to remove.

Coarseness, ﬁneness, and density of the ﬁber: In these studies it has
been found that coarse, harsh-bodied cottons clean better than ﬁne, silky
cottons and, as a rule, produce higher grades. According to Table 1,
Ducona, a ﬁne, silky cotton, averaged low middling for four years, while
Gorham’s Lone Star, a heavy-bodied cotton, averaged strict low middling,
or one grade higher than Ducona. A good comparison between two closely
related Mebane strains is found in Table 2. Mebane 96 having dense
ﬁbers graded strict middling, while Mebane 95 with thin, sparse ﬁbers
graded middling, or one grade in favor of the dense-ﬁbered strain.

Length of staple: Longer staple cottons have a tendency to twist or
rope in the cleaning machinery, resulting in poorer cleaning and gin
cutting in the ginning process and, consequently, lower grades.

Mechanical and Other Factors

Factors other than varietal characteristics that may affect the grade of
cotton harvested with machinery are: (1) injury to ﬁber by harvester,
(2) injury to ﬁber by extractor, (3) injury to ﬁber by cleaning equip-
ment, (4) weather conditions between the time the boll opens and har-
vest, and (5) length of time cotton is left exposed in the ﬁeld.

Injury to ﬁber in harvesting and ginning: Injury of the ﬁber by the
mechanical harvester is mostly in the form of stains from crushed green
leaves. In extracting and cleaning, the extracting saws, beaters, and
other mechanical devices may either machine or cut the ﬁber or twist
it so that gin cutting occurs when the cotton is ginned and thus affects
the grade.

Exposure to weather: Studies made on grade, strength, and color of
raw cotton as affected by exposure in the ﬁeld (reported in Texas Sta-
tion Bulletin 538) (3) indicate that, on the average, cotton dropped one
grade when left exposed in the ﬁeld for four weeks. Weather conditions
were found to be an important factor in lowering the grade. Table 1
shows that at College Station in 1935 and 1936, when cotton harvesting
was delayed until early October, the average grades for all varieties
were low middling and low middling minus, respectively. For 1937 and
1938, however, when cotton was harvested in late August and early Sep-
tember, the average grades for all varieties were strict low middling plus
and strict low middling, respectively. At Lubbock where harvesting tests
were conducted within a few days of the same date each year, under
varying weather conditions, the average grades for all varieties were

MECHANICAL HARVESTING OF COTTON 39

strict low middling spot in 1936, middling plus in 1937, and strict
middling in 1938 (Table 2), indicating that weather conditions and
exposure prior to harvest had a decided inﬂuence on the grade of cotton
harvested.

GRADE DIFFERENCES ATTRIBUTED TO MECHANICAL
HARVESTING OF DIFFERENT VARIETIES OF COTTON

In comparing the grade differences between hand-picked and machine-
harvested samples of cotton of the same variety, at College Station
(Table 4) it was found that the differences ranged from one-half grade
for Mebane 140 to two and one-half grades for Kubela in favor of the
hand-picked samples. Ten of the 15 varieties compared showed an average
difference of one and one-half grades in favor of hand-picked cotton over
machine-harvested cotton. The average difference for all varieties com-
pared was also one and one-half grades in favor of hand-picking. At
Lubbock (Table 5) the grade differences between hand-snapped and ma-
chine-harvested samples ranged from one-half grade in favor of machine
harvesting for Acala to three grades in favor of hand-snapping for Du-
cona. Three of the varieties showed no difference between hand-snapping
and machine-harvesting, while four varieties showed only one-half grade in
favor of hand-snapping over machine-harvesting. The average difference
for all varieties compared was three-fourths of a grade in favor of hand-
snapping. It appears, therefore, that the grade differences between
varieties may be attributed largely to the differences in the character-
istics of the varieties.

SNAPPING QUALITIES OF COTTON BOLLS

A varietal characteristic which has a bearing on the suitability of a
variety for mechanical harvesting is the snapping qualities of the bolls.
Bolls that are hard to snap off or pull from the plant may cause higher
percentages of loss with the stripper-type harvester. On the other hand,
those bolls which break off at the least touch are not suitable for the
mechanical picker, because the machine does not have a chance to remove
the cotton from the boll. A well-anchored boll is desirable for hand-
picking, as time is lost if the boll breaks off when an attempt is made
to pick the cotton for both hands of the laborer must be employed in
separating the cotton from the bur. “Cotton snappers” and “cotton
pullers” often complain that cotton bolls are hard to snap from the
plants of some varieties.

To obtain data on the pounds of pull required to snap cotton bolls
from the plant, the following changes were made in a Chatillon Quick
Stop scale: The dial was equipped with both a tight and a loose pointer.
The glass cover was removed, and the dial face was made of brass. A
special cradle consisted of a weighted fork having two curved prongs
spaced about one-eighth, inch apart (Fig. 15). In operation the forked
prongs were hooked under the boll and tension was applied (Fig. 16. The

40 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Figure 15. A quick-stop scale used in the boll-
' pulling tests. Note the prongs of the fork
to catch under the bolls and the loose pointer
to facilitate reading.

l

tight pointer carried the loose pointer around the dial until the boll
snapped oﬂ’. The tight pointer returned to zero, while the loose pointer
remained at the extreme point of travel, permitting : the dial to be read.

The data in Table 10 show that the average pull on varieties tested
at College Station ranged from 2.5 pounds for New Boykin to 7.6 pounds
for Ducona and 8.5 pounds for Ferguson 406. The general average for
all varieties tested was 4.7 pounds. The data indicates that the pull
required varies from year to year for the same varieties. This is
attributed to seasonal conditions and the condition of the plant.

At Lubbock the same varieties did not react in the same manner as
at College Station. For example, Ducona bolls were hard to pull at
College Station but comparatively easy at Lubbock, but Cut Leaf x Acala
and Cut Leaf x Clark were harder to pull at Lubbock than at College
Station (Table 10). Lightning Express x Westex was the most uniform
of the varieties tested. The difference in pounds pull for the same
varieties at College Station and Lubbock may be attributed largely to
climatic conditions and length of time the boll had been open before
pulling.

MECHANICAL HARVESTING OF COTTON

Figure 16. Pulling cotton bo-lls
with special quick-stop scale.

41

Table 10. Average pounds of pull required to remove cotton bolls from the plant*
College Station Lubbock
Pounds Pull Pounds Pull
Variety

1935 1936 1937T 1938 Av. 1937 1938 Av.
Ducona . . . . . . . . . . . . . . . . . . . . . . .. 7.5 8.1 4.6 10.0 7.6 . . . . .. 2.8 2.8

Gorhanfs Lone Star . . . . . . . . . . . .. 6.0 8.5 5.1 3.0 5.6 . . . . . . . . . . . . . . . . ..

Kubela . . . . . . . . . . . . . . . . . . . . . . . .. 7.4 . . . . .. 4.7 3.0 5.0 8.4 4. 6.4

Price’s Cut Leaf Acala . . . . . . . . . . . . . . .. 4.4 4.3 2.6 3.8 . . . . . . . . . . . . . . . . . .

Kelly’s Lone Star . . . . . . . . . . . . . .. 5.4 6.4 4.8 . . . . .. 5.5 . . . . . . . . . . . . . . . . ..

Startex . . . . . . . . . . . . . . . . . . . . . . . .. 8.3 . . . . .. 4.1 3.1 5.1 . . . . . . . . . . . . . . . . ..

Rothcamp’s Cluster . . . . . . . . . . . . . 6.4 7.0 . . . . . . . . . . . . 6.7 . . . . . . . . . . . . . . . . . .

New Boykin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.0 2.1 2.5 . . . . . . . . . . . . . . . . ..

Mebane 140 and 141 . . . . . . . . . . .. 8.4 . . . . .. 3.5 3.9 5.2 . . . . . . . . . . . . . . . . ..

Cut LeafxAcala................ . . . . . . . . . . . . . . . . .. 2.8 2.8 4.6 .1 3.8

C_ut Leaf x Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.0 3.0 6.6 . . . . .. 6.6

Llghtnlng Express x Westex . . . . . . . . . . . . . . . . . . . . . .. 3.8 3.8 4.7 3.2 3.9

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5.0 5.0 7.5 3.7 5.6

h/Iebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.5 4.5 4.1 . . . . .. 4.1

hlacha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . . . .. 3.3 3.3

Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . .. 2.1 2.1

Burnett . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5.3 3.2 4.3

Ferguson 406 . . . . . .. . . . . . . . . . . .. 8.5 . . . . . . . . . . . . . . . . .. 8.5 . . . . .. 5.6 5.6

Rogefs Cluster. . . . . . . . . . . . . . . . . 4.3 . . . . . . . . . . . . . . . . . . 4.3 . . . . . . . . . . . . . . . . . .

Klnslefs Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 4.1 . . . . . . . . . . . . . . . . . .

Delta and Pine Land . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.0 2.0 . . . . . . . . . . . . . . . . ..

Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.0 3.0 6.6 . . . . .. 6.6

. . . . . . . . . . . . . . . . . . . . . . . . . .. 6.2  6.2 

Average . . . . . . . . . . . . . . .. 7.0 6.9 4.1 3.7 4.7 6.0 3.5 4.6

*Tests Were made each year iust before the harvesting tests were made.
TFrom thesis of H. T. Stewart on “A Study of the Snapplng Qualities of Cotton Bolls.”

42 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

A comparison of the machine efﬁciency of the Texas Station Harvester
(Tables 1 and 2) with the pounds of pull (Table 10) does not show a
close relationship between eﬁiciency and pull, as shown by simple cor-
relation studies made on 14 varieties grown at College Station in 1938.
Other varietal characteristics, such as plant type, size of boll, and strength
of boll, may have counteracted the inﬂuence ofpull.

Seasonal conditions and age of plant appear to have considerable in-
ﬂuence on the snapping qualities of cotton bolls. In 1937 at College
Station, Stewart (10) made tests at approximately two-week intervals, or
on August 10 and 26 and September 8 and 22. Prior to August 10 the
weather was hot and dry with no rainfall and light dews. From August
10 to 26 light showers occurred on six days. The mornings were mostly
damp and foggy, and all except four days were either cloudy or partly
cloudy. The weather continued damp and cloudy from August 26 to
September 8 with light showers on ﬁve days. No rain fell between the
third and fourth tests or from September 8 to 22.

The average pull for the ﬁrst tests following several days of dry
weather was 8.9 pounds (Table 11). The pull decreased as the season
advanced, with damp rainy weather, to 4.5 pounds for the second test
on August 26 and 4.1 pounds on September 8. After several dry days
the pull increased to 4.4 pounds for the test made on September 22.

Table 11. Inﬂuence of season on pounds of pull required to remove cotton bolls from the
plant at College Station*
1937 1938
Variety
Aug Aug. Sept. Sept Av Aug. Sept Av
10 26 22 16 3
Fer uson’s New Boykin . . . . . . . .. 6.1 2.1 3.0 3.2 3.6 2.9 2.1 2.5

Me ane 140 . . . . . . . . . . . . . . . . . . .. 7.4 4.7 3.5 3.9 4.9 3.3 3.9 3.6

Startex . . . . . . . . . . . . . . . . . . . . . . . .. 8.5 6.5 4.1 4.1 5.8 1.8 3.1 2.4

Gorham’s Lone Star . . . . . . . . . . . .. 10.9 3.6 4.1 4.2 5.7 5.0 3.0 4.0

Price’s Cut Leaf Acala . . . . . . . . .. 7.2 5.3 4.3 3.4 5.0 1.9 2.6 2.2

ucona . . . . . . . . . . . . . . . . . . . . . . .. 10.6 4.1 4.6 5.8 6.2 5.8 10.0 7.9

Kubela . . . . . . . . . . . . . . . . . . . . . . . .. 9.6 6.4 4.7 4.4 6.2 4.6 3.0 3.8

Kelly’s Lone Star . . . . . . . . . . . . . .. 10.9 3.5 4.8 6.4 6.4 . . . . . . . . . . . . . . . . ..

Lightning Express x Westex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.7 3.8 3.2

Clark (late) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.2 5.7 5.0

Cut Leaf x Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.9 3.0 2.5

Cut Leaf x Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.2 2.8 2.5

Kinslefs Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 4.1 4.7

Delta and Pine Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.4 2.0 1.7

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.6 5.0 4.8

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.1 4.5 4.3

Average . . . . . . . . . . . . . . .. 8.9 4.5 4.1 4.4 5.5 3.4 3.9 3.7

*From thesis of H. T. Stewart on “A Study of the Snapping Qualities of Cotton Bolls.”

Table 11 also shows results obtained on August 16 and September 3,
1938. On August 10, 1.27 inches of rain fell, and light showers occurred
on August 11 and 13. Heavy dews prevailed, and a large percentage of
the days were cloudy through September 3. The cotton plants were suc-
culent and growing during the period of these tests; consequently, there
was only .5 pound difference in the averages of the two tests. These

“.2. .. _....__t.._4. _. .... x-i‘ ._ A. _._...,_.__.1_.__... ._1-.'..__.....1.._.h

MECHANICAL HARVESTING OF COTTON 43

results clearly indicate that the snapping qualities of cotton bolls are
greatly inﬂuenced by Weather conditions, which affect the cotton plants.

In the boll-pulling tests data were kept on the percentage of bolls that
pulled off with the peduncle attached and the percentage of peduncles
that pulled off with the limbs attached to them. The data in Table 12
show that when harvesting is delayed until October, as it was at College
Station in 1935 and 1936, the bolls disintegrate and become weak so that
they crush when an attempt is made to pull them. In 1936, 36 per cent
of the bolls were crushed and 64 per cent were pulled off with the
peduncles attached. The season of 1935 was not as Wet as that of 1936,
and 93 per cent of the bolls pulled had the peduncle attached to them.
In 1937 and 1938 harvest was in late August and early September, and
98 to 100 per cent of the bolls pulled oif with the peduncles attached
(Table 12). Equally high percentages were obtained at Lubbock in 1936
and 1938 while the plants were in good condition and not damaged by
damp weather. No tests were made at Lubbock in 1937.

An examination of the plants after stripping with the machine, and of
the harvested bolls veriﬁed the above data. It was also found that when
the peduncle remained on the plant, the boll crushed, as often part of
the bur was attached to it. A comparison of the machine efﬁciency data
in Tables 1 and 2 with the data in Table 12 shows that varieties having
a high percentage of the bolls crushed were lower in machine efﬁciency.

Varieties of cotton with comparatively small, strong, wiry branches are
the most suitable for harvesting with the mechanical stripper. The data
in Table 12 shows the percentage of peduncles that had limbs attached
to them in the pull tests at both College Station and Lubbock. In these
tests any section of one-half inch or more in length which broke off
with the peduncle was classed as a limb.

In 1936 at College Station damp rainy weather prevailed prior to har-
vest, which was seasonably late, and the plants were succulent, sappy,
and brittle. As a result, an average of 33 per cent of the bolls pulled
off with the limbs attached to the peduncle. The averages were only
5 to 7 per cent for tests made in 1935 during dry weather and in 1937
and 1938 when harvesting was done early.

The percentages at Lubbock were generally much higher (Table 12),
as the cotton was irrigated and cool weather kept the plants vigorous.
Varieties with a lower percentage of limbs than the general average
are Ducona, Lightning Express X Westex, Macha, and Cut Leaf x Acala.
Varieties which had a high and undesirable percentage of limbs are Me-
bane 96, Acala, Clark, Kinsler’s Cluster, and Cut Leaf x Clark.

A large number of limbs makes extracting and cleaning more difficult
and increases the amount of trash left in the seed cotton. Long limbs
are especially objectionable, as they may have several leaves attached and
have a tendency to wrap around shafts and sprockets and obstruct pas-
sageways. They are hard to extract unless broken into several short
pieces.

Table 12. Percentage of Peduncles Attached to Bolls and Limbs Attached to Peduncles When Pulled from Plants at
College Station and Lubbock

 
 
  
 

Peduncle attached to boll

Limbs attached to peduncle

Variety College Station Lubbock College Station Lubbock
1935 1936 1937 1938 Av. 1936 1938 Av. 1935 1936 1937 1938 Av. 1936 1938 Av.
Ducona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 56 100 92 86 . . . . . .. 100 100 0 40 8 16 16 . . . . . . . 4 4

Gorham's Lone Star . . . . . . . . . . . .. 88 52 100 100 85 . . . . . . . . . . . . . . . . . . . .. 12 44 2 4 16 . . . . . . . . . . . . . . . . . . . ..

Ku . . . . . . . . . . . . . .. 100 . . . . . .. 100 - 100 100 100 100 100 4 . . . . . .. 6 4 5 40 24 32

Price’s Cut Leaf Acala . . . . . . .. 84 100 96 93 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16 6' 0 7 . . . . . . . . . . . . . . . . . . . ..

Kelly’s Lone Star. . . . . 96 52 100 . . . . . . . 83 . . . . . . . . . . . . . . . . . . . .. 4 44 10 . . . . . .. 19 . . . . . . . . . . . . . . . . . . . ..

Startex . . . . . . . . . . . . . . . . . . . . . 92 . . . . . . . 100 100 97 . . . . . . . . . . . , . . . . . . . . . 0 . . . . . . . 2 4 2 . . . . . . . . . . . . . . . . . . . . .

Rothcamp's Clusten. . . . . . . . . . . . . .. 92 76 . . . . . . . . . . . . .. 84 . . . . . . . . . . . . . . . . . . . .. 20 20 . . . . . . . . . . . . .. 20 . . . . . . . . . . . . . . . . . . . ..

NewBoykin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100 100 100  0 0 0 . . . . . . . . . . . . . . . . . . . ..

Mebane 140 and 141 . . . . . . . . . . . . . . . . .. 84 . . . . . .. 100 100 95. . . . . . . . . . . . . . . . . . . . .. 0 . . . . . .. 6 4 3 . . . . . . . . . . . . . . . . . . . ..

Cut Leaf x Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 100 96 100 98 . . . . . . . . . . . . . . . . . . . . . 24 24 24 28 26

Cut Leaf x Clark . . . . .., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96 96 92 . . . . . .. 92 . . . . . . . . . . . . . . . . . . . .. 0 0 44 . . . . . .. 44

Lightning Express x Westex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96 96 96 100 98 . . . . . . . . . . . . . . . . . . . .. 4 4 20 32 26

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96 96 96 100 98 . . . . . . . . . . . . . . . . . . . .. 0 0 40 56 48

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 100 88 . . . . . . . 88 . . . . . . . . . . . . . . . . . . . . . 0 0 28 . . . . . . . 28

Macha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 28

Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 60

Burnett . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . 96 100 98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 8 26

Ferguson 406 . . . . . . . . f. . . . . . . . . . . . . . .. 92 . . . . . . . . . . . . . . . . . . . .. 92 . . . . . .. 100 100 0 . . . . . . . . . . . . . . . . . . . .. 0 . . . . . .. 24 24

Roger's Cluster . . . . . _ . . . . . . . . . . . . . . . .. 96 . . . . . . . . . . . . . . . . . . . .. 96 . . . . . . . . . . . . . . . . . . . .. 28 . . . . . . . . . . .  . . . . . .. 28 . . . . . . . . . . . . . . . . . . . ..

Kinslefs Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8 . . . . . . . . . . . . . . . . . . . . .

Delta and Pine Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 0 0 . . . . . . . . . . . . . . . . . . . ..

Clark (late) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100 100 100 . . . . . .. 100 . . . . . . . .. . . . . . . . . . . .. 4 4 40 . . . . . .. 40

H. X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 . . . . . . . . . . . . . . . . . . . . . 92 . . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . .
Average ...................... .. 93 64 100 9s 95 99 100 9s 7 93 5 5 s I 35 l 29 92

W’

NOI-LVLS LNEINIHHJXH TVHILI/IIIOIHDV SVXEIL ‘O89 ‘ON NLLEPTIIIEI

MECHANICAL HARVESTING OF COTTON 45

EFFECT OF BOLL SPREAD ON HARVESTING AND
EXTRACTING QUALITIES

The cotton bolls collected in the pounds of pull tests were measured to
determine how Wide the average bolls spread open. This Was done by
placing the bur on a protractor, as shown in Figure 17. Table 13 shows
data for several varieties at College Station and Lubbock for the years
1937 and 1938. At College Station, the average degree of spread of the
boll carpels ranged from 89 degrees for Kelly’s Lone Star to 140 degrees

vfor Lightning Express X Westex, while at Lubbock the range was from

103 degrees for Macha to 125 degrees for Cut Leaf x Clark. The general
average for all varieties Was 120 degrees at College Station and 115
degrees at Lubbock.

Figure 17. Method used to measure the degree of boll spread of cotton bolls.

From a study of Table 14 it appears that weather conditions at College
Station during the season affected the degree of boll spread. For ex-
ample, the hot dry Weather prior to August 10, 1937, caused the average
to be wider, or 131 degrees, but prevailing damp weather from August
10 to September 8 reduced the average spread on August 26 to 114 de-
grees and on September 8 to 101 degrees. During clear Weather from
September 8 to 22 the spread increased from 101 to 106 degrees. In
1938, when more uniform weather prevailed throughout the season, the
degree of boll spread did not vary greatly from August 16 to September
3 (Table 14).

46 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION

Table l3. Average degree of boll spread for several varieties of cotton at College Station
and Lubbock*

College Station Lubbock
Variety
1937 1938 Average 1937 1938 Average
Ducona . . . . . . . . . . . . . . . . . . . . . . . .. 116 131 124 . . . . . . .. 106 106

Gorham’s Lone Star . . . . . . . . . . . . . 99 120 110 . . . . . . . . . . . . . . . . . . . . . . . .

Price’s Cut Leaf Acala . . . . . . . . . .. 112 120 116 . . . . . . . . . . . . . . . . . . . . . . ..

Kelly’s Lone Star . . . . . . . . . . . . . . . . 89 . . . . . . . . 89 . . . . . . . . . . . . . . . . . . . . . . . .

Startex . . . . . . . . . . . . . . . . . . . . . . . . . . 92 120 106 . . . . . . . . . . . . . . . . . . . . . . . .

New Boykin . . . . . . . . . . . . . . . . . . . . . 93 122 108 . . . . . . . . . . . . . . . . . . . . . . . .

Mebane 140 and 141 . . . . . . . . . . . .. 108 124 116 . . . . . . . . . . . . . . . . . . . . . . ..

Kubela . . . . . . . . . . . . . . . . . . . . . . . . . . 100 139 120 125 124 124

Cut Leaf x Acala . . . . . . . . . . . . . . . . . . . . . . .. 125 125 115 113 114

Cut Leaf x Clark . . . . . . . . . . . . . . . . . . . . . . .. 122 122 125 . . . . . . .. 125

Lightning Express x Westex . . . . . . . . . . . . .. 140 140 126 115 120

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 130 113 109 111

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 135 120 . . . . . . . . 120

Macha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 103

Acala . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . 117 117

Burnett . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 104 110

Ferguson 406 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 108

Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 . . . . . . . . 117

Kinsler’s Cluster . . . . . . . . . . . . . . . . . . . . . . . . . 125 125 . . . . . . . . . . . . . . . . . . . . . . . .

Delta and Pine Land . . . . . . . . . . . . . . . . . . .. 118 118 . . . . . . . . . . . . . . . . . . . . . . ..

Clark (late) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 138 . . . . . . . . . . . . . . . . . . . . . _ . .

Average . . . . . . . . . . . . . . . . . 101 127 120 120 111 115

*Average of 25 bolls for each variety.

Table 14. Inﬂuence of season on average degree of boll spread at College Station*

1937 1938
Variety
Aug Aug Sept. Sept Aug Sept
Av. Av
New Boykin . . . . . . . . . . . . . . . . . . .. 124 117 98 96 109 122 99 110

Mebane 140 . . . . . . . . . . . . . . . . . . .. 131 122 108 117 120 124 112 118
Startex . . . . . . . . . . . . . . . . . . . . . .
Gorham’s Lone Star . . . . . . ..
Price’s Cut Leaf Acala. . . . .

  
   

Ducona . . . . . . . . . . . . . . . . . .. 124 131 113 122

Kubela . . . . . . . . . . . . . . . . . . . . . 111 139 121 130

Kelly’s_ Lone Star . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lightning Express x Westex. . . . . . .. 140 142 141

Clark (late) . . . . . . . . . . . . . . .. 138 128 133

Cut Leaf x Clark . . . . . . . . . . . 
Cut Leaf x Acala . . . . . . . . . . . . . ..

   

Kinsler’s Cluster . . . . . . . . . . . . . . . . 125 132 128

Delta and Pine Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 118 123 120

Mebane 96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 114 122

Mebane 95 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 123 129

Average . . . . . . . . . . . . . . . . 131 114 101 106 113 127 120 124

*Average of 25 bolls for each variety.

The general impression among growers using common varieties is that
wide spreading bolls reduce storm resistance, but at both College Station
and Lubbock the Lightning Express x Westex cross, with an average
boll spread of 140 and 120 degrees, respectively, for the two locations,
had an extremely loW storm loss. At Lubbock the Lightning Express

MECHANICAL HARVESTING OF COTTON 47

x Westex cross compared favorably in storm resistance with the narrow
spreading Macha.

Lightning Express x Westex harvested Well, with a machine efficiency
of 94.9 per cent at College Station and 98.6 per cent at Lubbock (Tables
1 and 2). The grade, staple, and yields were satisfactory. The burs
were light and a high percentage of clean seed cotton was obtained
(Tables 8 and 9). The inter-seed drag and a relatively coarse harsh
ﬁber enhanced its extracting and cleaning qualities. .

RELATION OF YIELD TO THE EFFICIENCY OF THE
HARVESTER

Yield did not appear to inﬂuence the efficiency of the Texas Station
Harvester greatly, as indicated by the correlation coeﬁicient of .421 be-
tween yield and eﬁiciency for the year 1938. This coeﬂicient is not sig-
niﬁcant on the 5 per cent level (11). The machine seemed to harvest
equally well, under comparable conditions of plant type and growth, cotton
making high or low yields.

An average machine eﬂiciency of 98.2 per cent was obtained at Lub-
bock in harvesting relatively small cotton plants yielding a bale to the
acre, while at College Station where the plants grew large the average
efﬁciency was 92.1 per cent for cotton yielding about one-half bale to
the acre for the years 1935 to 1938, inclusive (Tables 1 and 2). This
difference in machine efﬁciency at Lubbock and College Station may be
attributed more to size of plants than to acre yield, as has been previously
pointed out.

SUMMARY AND CONCLUSIONS

A number of commonly grown varieties and several new strains of
cotton developed by means of selection, crossing, and backcrossing were
tested during the four-year period 1935-1938 to ascertain their harvesting,
extracting, and cleaning characteristics.

A stripper-type harvester and an extractor, developed by the Texas
Agricultural Experiment Station, were mounted on a tractor and used
to study varietal characteristics inﬂuencing machine eﬁiciency and ex-
tracting qualities of different varieties 0f cotton. The cleaning qualities
were tested with the Station Cylinder Cleaner.

Factors affecting the efficiency of cotton harvesting machinery are
classed as varietal characteristics, mechanical factors, and cultural
methods.

Varietal characteristics affecting machine efficiency are: shape of plant,
height of plant, length of branches, number of branches, density of
foliage, type of boll, bolls borne singly or in clusters, storm resistance,
degree of boll spread, ﬁuﬁiness of the cotton, brittleness of branches and
boll peduncles, and height of ﬁrst branches above ground.

The best plant type for both the mechanical stripper and the picker
is one having relatively short but numerous fruiting branches with short

48 BULLETIN NO. 580, TEXAS AGRICULTURAL EXPERIMENT STATION
nodes, no vegetative branches, an open type growth, light foliage, storm
resistance, and a large, strong boll on a single peduncle which will snap
easily under tension but will withstand considerable plant agitation.

Plants at College Station averaging 30 to 32 inches in height gave an
average machine eﬂiciency of 92.1 per cent, while at Lubbock Where the
plants averaged from 20 to 24 inches in height the average efficiency
was 98.2 per cent. Varieties producing numerous long branches gave
lower eﬂiciency than varieties with shorter branches.

Plant characteristics appear to aﬁect machine eﬁiciency more than
either mechanical factors or cultural methods.

At College Station hand-picked cotton averaged middling plus; hand-
snapped, middling; and machine-harvested, strict low middling (one-half
grade difference in hand-picked and hand-snapped and one and one-half
grades diﬁerence in hand-picked and machine-harvested cotton). At
Lubbock for two years both the hand-picked and hand-snapped cotton
averaged strict middling with a slight difference in favor of the hand-
picked cotton. In 1937 machine-harvested cotton averaged one grade lower
than hand-snapped cotton, but in 1938 the average for the three methods
of harvesting was strict middling.

Factors inﬂuencing the eiﬁciency of an extractor are: feeding rate; rate

of ﬂow of material through machine; speed of extractor saws; compact-l

ness; uniformity of distribution; agitation; amount of burs, unopened bolls,
limbs, sticks, and leaves; size of boll; shape of boll; weight of bur; degree

of boll spread; ﬂufﬁness; storm resistance; ﬁber drag; and length of
staple.

Cleaning of cotton is inﬂuenced by previous handling, amount and kind
of trash, type of cleaner, speed of cleaner parts, kind and condition of
screen, rate of feeding, density of ﬁber on seed, ﬁneness of ﬁber, length
of ﬁber, and moisture content.
bodied cotton than from ﬁne, silky cotton.

Trash is easier to remove from coarse- <

The grade of mechanically harvested cotton is affected by the amount l

of trash; kind of trash; weather conditions; time of exposure; ﬁber injury 1
by harvester, extractor, cleaner, and gin; and ﬁber characteristics such i

as ﬁneness, density, and length.

Cotton bolls that are hard to pull from the plant may cause higher 4
percentages of loss with the stripper-type harvester, while bolls that snap Y

off too easily are not desirable either.

The general average degree of spread of cotton bolls for all varieties ,

tested was 120 degrees at College Station and 115 degrees at Lubbock.
The average acre yield of cotton harvested with the Texas Station

Harvester ranged from about one-half bale at College Station to ap- g

proximately a bale at Lubbock. The harvester will harvest low or high

yields equally well if under comparable conditions of plant type and 

growth.

MECHANICAL HARVESTING OF COTTON ,49

ACKNOWLEDGMENTS

The thanks of the authors are due to Professor J. G. Powers, oﬂicial
and licensed cotton classer of the Department of Textile Engineering,
of the Agricultural and Mechanical College of Texas, for classing the
samples of hand-picked, hand-snapped, and machine-harvested cotton.

Thanks are also due to Mr. F. H. Lacy, assistant farm superintendent

of the Agricultural Farm of the Agricultural and Mechanical College of '

Texas, for his cooperation in growing cotton for these studies and for
the use of a tractor on which to mount the Station Harvester and Ex-
tractor during the harvesting tests.

REFERENCES

1. Bennett, C. A. and Gerdes, F. L. 1935. U. S. Department of Agri-
culture, Farmers’ Bull. 1748.

2. Brown, H. B. 1938. Cotton. McGraw-Hill Book Co., N. Y., p. 88.

3. Grimes, Mary Anna. 1936. The Effect of Exposure in the Field on
Grade, Strength, and Color of Raw Cotton. Tex. Agr. Expt. Sta.
Bull. 538, p. 35.

4. Killough, D. T. July 1929. A Study of Cotton Harvesters and
Adaptability of Varieties to Harvesting Machinery. Farm Machin-
ery and Hardware, Vol._ 5, N0. 1747.

5. Killough, D. T. February 1932. Breeding Varieties of Cotton to
Meet the Needs of Mechanical Harvesting. The Valley Farmer,
Vol. 5, No. 9. .

6. Smith, H. P. 1931. Cotton Harvesting Development to Date. Agri-
cultural Engineering, Vol. 19, No. 3, pp. 73-78.

7. Smith, H. P., Killough, D. T., Byrom, M. H., Scoates, D., and Jones,
D. L. 1932. The Mechanical Harvesting of Cotton. iTex. Agr. Expt.
Sta. Bull. 452, p. 72.

8. Smith, H. P., Byrom, M. H., Killough, D. T., and Jones, D. L. 1933.
The Heating of Cotton when Bulked and Its Effect on Seed and Lint.
Agricultural Engineering, Vol. 14, No. 10, pp. 280-284.

9. Smith, H. P., Killough, D. T., Jones, D. L., and Byrom, M. H. 1935.
Progress in the Study of the Mechanical Harvesting of Cotton.
Tex. Agr. Expt Sta. Bull. 511, p. 35.

g 10. Stewart, H. T. February 1938. A Study of the Snapping Qualities

of Cotton Bolls. Thesis, Agricultural and Mechanical College of
Texas. A

- 11. Fisher, R. A. 1932. Statistical Methods for Research Workers.

Fourth edition, Oliver and Boyd, London. Table V. A.