COTTON-SPACING EXPERIMENTS 41 
spacing of the plants usually promotes earliness in the crop, in some 
of the Greenville experiments the thinned rows gave the greatest 
yields in the first picking. In such cases it may be inferred that the 
plants in the unthinned rows were too close for the best results 
under the early-season conditions, but that they obtained a greater 
advantage from a favorable period later in the season. 
Comparing the behavior of different spacings on black land and 
on fine sandy loam, there appears to be a greater advantage in 
leaving the plants closely spaced on lghter soils, as the experiments 
on this type of land have given more outstanding differences in favor 
of the unthinned rows. 
CHOPPING AND ITS RELATION TO YIELDS 
Under the usual methods of growing cotton, chopping requires an 
expenditure of consider. ablelabor and money. As chopping is generally 
done hurriedly, losses from careless chopping are difficult to avoid, 
especially where the farms are large and much ‘of the help is hired. 
Many plants are chopped out which should remain in the field, 
especially if the stand is uneven. 
Chopping too early is often injurious (1, 2, 4, 5, 8).2, Many farmers 
begin chopping soon after the seedlings have appeared, even before 
the first pair of true leaves is well developed. If adverse conditions 
are encountered later the mortality of young cotton plants may be 
very high, and many may die of seedling disorders or from insect 
attacks (3). 
Repeated experiments have shown no advantage in very early 
thinning of cotton, but on the contrary increased yields and better 
stands are possible where the thinning is done at a later period, or 
not until the plants are 5 or 6 inches high and the danger of 
plants dying after thinning is not so great (2, 4,5). The seedlings 
erow better if they are left close together in the rows, especially “if 
adverse weather conditions are encountered (G)s ein fact, thinning 
may be unnecessary where the plants are not too thick in the row, 
unless the weeds are outgrowing the cotton. As maximum yields 
are more likely to be obtained from close spacing, chopping should be 
done with great caution. 
To get amore definite check upon the effects of chopping, a simple test 
was made in a field where the seedlings had come up to a very regu- 
lar stand. lJimmediately after chopping, 20 rows were selected and 
marked off into two sections 100 feet long. For each section a record 
was made of the number of hills, the number of skips over 2 feet long, 
the number of plants injured in chopping, and the number of surviv- 
ing plants. At picking time the number of mature bolls on each 
section was counted. 
As shown in Table 19, the number of mature bolls was found to 
be directly associated with the number of plants or of hills to the row. 
Where the number of plants or of hills is small, the number of bolls 
is usually low. The irregularity in the work of the individual chop- 
pers is also shown by the ‘differences in the numbers of plants remain- 
ing and the numbers of skips in the row.° 
2 The serial numbers (italic) in parentheses refer to ‘‘ Literature cited,’ 
3 These data were taken by Walter E. Clark, formerly assistant see ala, Office of Crop Acclima- 
tization, Bureau of Plant Industry. 
