COTTON-SPACING EXPERIMENTS 19 
done with a hoe, the plants were left at distances greater than was 
desired. (Table 8.) 
In this test there is a very definite difference in yield between the 
two spacings, especially in the first picking. In 8 out of 10 compari- 
sons, the two inside rows of the unthinned blocks produced more cot- 
ton than the chopped blocks. In one comparison the yield was a tie 
and in another a chopped block produced slightly more than the 
unthinned. 
The yields from both spacings are much higher on one side of sec- 
tion 1 than on the other side. (Fig. 8.) This gives the unthinned 
blocks some advantage in total yield, but since the yields are inter- 
preted on the basis of differences of the two inside rows of adjoining 
blocks of the different spacings, this advantage is small. 
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SELECTION 7 SLOTIONW 2 
Fig. 8.—Yields (in pounds) of seed cotton per row from comparison of chopped and unthinned 
rows, Campbell, Tex., 1923 
Considering yields from the two inside rows of each block, there is 
a mean difference of 1.28+0.204 pounds in favor of the unthinned 
rows. This difference is 6.4 times its probable error and is very 
significant. The mean difference corresponds to an increase of 10.8 
per cent in the unthinned rows, whereas the difference between the 
mean yields is 1.6 pounds, corresponding to an increase of about 13.5 
per cent. 
The results of this experiment are in marked contrast to the preced- 
ing experiment made on black land with the same two spacings. The 
comparison made on black land about 12 miles distant from this com- 
parison failed to show any significant differences in yield, whereas in 
this comparison the differences are very outstanding. 
