Comparing the 
yields from the 
two inside rows 
of each block in 
the different 
spacings, there is 
a mean difference 
of 1.24+0.097 in 
favor of the un- 
thinned rows. 
This difference is 
177 stlimes its 
probable error, 
which is decid- 
edly significant. 
The mean differ- 
ence corresponds 
to an increase oi 
22.2 per cent in 
the unthinned 
rows, whereas the 
difference be- 
tween the mean 
yields is 1.25 
pounds, corre- 
sponding to an 
increase of about 
22.4 per cent. 
Comparing ad- 
jacent outside 
and inside rows of 
the same blocks, 
the frequent 
higher yield of the 
outside rows otf 
the unthinned 
blocks and the 
lower yields of 
the outside rows 
of the thinned 
blocks show that 
the unthinned 
rows are more 
efficient produc- 
ers of cotton 
under very dry 
eonditions. The 
row yields in 
pounds of seed 
eotton are shown 
graphically in 
Figure 14. 
COTTON-SPACING EXPERIMENTS 31 
S51 
SLOIIONV 7 
POUNDS PE ROLF 
SOON OS PLR CO 
Zr 
POON PS PLE SCO 
OUTHNIED SPLAT GTLHED (SL AET LIRIWMN ED 1 PLT 
le SCA JE (NCA 421K 
Fig. 14.—Yields (in pounds) of seed cotton per row from comparison of one 
plant every 12 inches with unthinned rows, Greenville, Tex., 1925 
