June 14, 1924 
Spacing Experiments with Acala Cotton 
1091 
the error. In one comparison the 2-inch spaced block gave 0.36 of a pound less 
than the adjacent 6-inch spaced block, but this reduction is less than the 
probable error of either of the compared weights. However, as there is no signifi¬ 
cant difference between any of the blocks of like spacing each spacing can be 
treated as one array which gives an increase of 2-inch over 12-inch spaced plants 
of 2.44 ±0.355 pounds, which is 6.88 times the error, and an increase over 6-inch 
spaced plants of 1.54 ±0.344 pounds, which is 4.48 times the error. On this basis 
the writer finds that 2-inch spaced plants gave a significantly higher yield than 
6- or 12-inch spaced plants in the second picking. 
The total yields of the 2-inch spaced blocks gave an increase over adjacent 
12-inch spaced blocks in every comparison. The increases are 3.39 ±0.675, 2.44 ± 
0.70, 2.13 ±0.489, which are 5.02, 3.47, and 4.36 times the error and can be con¬ 
sidered significant. 
Although 2-inch spaced blocks outyielded adjacent 6-inch blocks in all but 
one case, where the difference was only 0.21 of a pound, these differences can not 
be considered significant. 
Since there is no significant difference in total yield between any of the blocks 
of like spacing each spacing can be treated as one array, as with the first and 
second picking. On this basis the 2-inch spaced plants show an increase of 2.77 ± 
0.441 pounds over 12-inch spaced plants, which is 6.28 times the error. The in¬ 
crease of 2- over 6-inch spaced blocks, however, is only 0.95 ±0.5, which should 
not be considered significant. 
The mean yield of the first, second, and total pickings of 123.5 feet of row space 
is shown for each spacing in Table V. 
Table V. —Mean yields of the first, second , and total pickings of 128.5 feet of 2 , 6 , 
and 12-inch spaced plants , Coachella Valley , 1923 
Spacing 
First 
picking 
Second 
picking 
Total 
yield 
2-inch.. ________ 
Pounds 
15.55±0.25 
16.14± . 29 
15. 22=t . 26 
Pounds 
10.75=fc0.27 
9.21± .34 
8.31=fc . 23 
Pounds 
26.30db0.24 
25.35± .45 
23. 53=fc . 37 
6-inch.... .. ___ 
12-inch__ ____ 
The results of the 1923 test not only substantiate the conclusion drawn from 
the 1922 test, that no reduction in yield occurs when plants are left as close 
together as 2 inches in the row, but indicate that increased yields may be secured 
from close-spaced plants. Although the first picking of the 1923 test showed no 
increase in the yields of the 2-inch spacings over the 6-inch and 12-inch, the 
2-inch spacings forged ahead in the second picking, and gave significant increases 
in yield. 
With plants spaced as close as 2 inches in the row there is a tendency to sup¬ 
pression or restriction of the development of the lower fruiting branches, but even 
in the first picking it is shown that this handicap is made up by the larger num¬ 
bers of plants, so that the yields were not reduced below that of 6- or 12-inch 
spaced plants. The same degree of crowding does not continue throughout the 
season, as weaker plants are overtopped by their more vigorous neighbors, and 
as they become larger the plants spread apart, so the rows appear wider and the 
foliage less dense, allowing a full crop of bolls to be set and matured. 
Figure 3 shows the block yields of the first and second picking of the different 
spacings for both the 1922 and 1923 experiments. It can readily be seen that the 
yields were about the same in the 1922 test, but the 1923 test shows a rather con¬ 
sistent alteration in block yields, the higher yields being coincident with the 2-inch 
spacing. 
