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28 BULLETIN 1473, U. S. DEPARTMENT OF AGRICULTURE 
COMPARISON OF CHOPPED AND UNTHINNED ROWS AT CAMPBELL, TEX. 
In 1924 another test comparing chopped rows with unthinned rows 
was made on a farm near Campbell. The choppers were instructed 
to chop out the rows, leaving one or two plants in hills about 12 inches 
apart. The experiment was exposed to a heavy infestation of grass- 
hoppers after thinning, causing the loss of a great many terminal 
buds, which may be partly responsible for the wide variations in row 
yields. (Fig. 13 and Table 13.) 
Section 1 shows considerable variation in block yields as well as in 
row yields. There is a gradual increase in yields from successive 
blocks of the same spacing across the first section. Sections 2 and 
vena 
o 
< 
Vs 
\ # < e Ki KI 
x PS x ease 
% nN RK 
N SI BLT HT] BRT] | Boe 
\ RS REREY REET || PRR 
Se ‘ BREE || ep ppy tt basa 
S ¢ ited ae 
q 3 etiees 
K) > 
ee 
CMPLD UR CHOPPED «UN- CHPPED Un- CHOPPED = CHOPPED W- HOPED Wht CHOPPED Wt- CHOPPED 
THIMWED —  ‘THINWED TWIWWED TWWMED TWIMMED THWHED 
SLO7IONWV FS SLOTIOV 
3 do not show this 
condition but do 
show some wide 
\ differences in row. 
v & aif yields from thesame 
y £S KY blocks¢ In@i50 ut 
‘ ws BR KS of 18 block compari- 
, Sh NS x sons of inside rows 
Q RIS % ae) a the unthinned 
N 1<K% : ese blocks gave the 
N % highest yields. The 
mean difference in 
yield from the two 
inside rows of each 
3 block of the two 
a 
CHOPPLD UWTHINNED CHOPPED UN THINMED CHOPPED LA THINNED CHOPPED : : 
SECTION F Spacings is 0.628 
Fic. 13.—Yields (in pounds) of seed cotton per row from comparison +0. 144 po und, 
of chopped and unthinned rows, Campbell, Tex., 1924 which is 4.4 times 
the probable error of the difference and may be regarded as signifi- 
cant. The mean difference corresponds to an increase of 9.1 per cent 
in the unthinned rows, whereas the difference between the mean 
yields is 0.6 pound, corresponding to an increase of about 8.8 per cent. 
There was little difference in the rate of maturity between the two 
spacings. Each spacing had opened about 60 per cent of its crop on 
the date of first picking. 
. 
