SINGLE-STALK COTTON CULTURE AT SAN ANTONIO. 3 
Usually the boll weevils do not appear in sufficient numbers to 
interfere materially with the setting of the crop before the first of 
July. During seasons of continued drought they are unable to 
reproduce rapidly enough to overcome the mortality caused by the 
falling of punctured squares and the action of the hot, dry atmos- 
phere, and consequently they inflict little damage. In other words, 
drought is to a degree a beneficial factor in the production of a cotton 
crop in this region.1. During more humid seasons, however, weevils 
infest practically all buds and squares by the middle of July. 
From these facts it will be seen that cotton crops in the region of 
San Antonio must ordinarily be set. within a month or a month and a 
half after flowering begins. Under the ordinary system of wide 
spacing, yields are usually rather low, averaging less than half a bale 
to the acre. During the season of 1914, however, nearly a bale to 
the acre was secured by the single-stalk system. Moreover, the bolls 
that produced this crop were set in less than 30 days. 
The season of 1914 was exceptional only in the distribution of the 
rainfall, which tended to shorten the period of setting the crop. 
While the normal rainfall for April and May, respectively, is less than 
3 inches, in 1914 more than 6 inches fell during each of these months. 
No rain fell from the first of June until the middle of August, so that 
a continued drought followed an extended period of rainfall. 
PLAN OF TEST. 
A plan of the field on which the ordinary system of wide spacing 
and the new single-stalk system of cotton culture were tested and 
compared in 1914 is shown in figure 1. In order to facilitate com- 
parisons, the field was divided into four sections, which are desig- 
nated as A, B,C, and D, respectively. All of the sections were planted 
with the same variety of cotton, Acala, a promising new type recently 
acclimatized from Mexico, which has given excellent results for several 
seasons at San Antonio. 
In section A the two systems were compared in alternating rows; 
that is, single rows in which the plants were thinned early to 2 feet 
apart alternated with single rows in which the plants were thinned 
late and left less than 10 inches apart. 
In section B 4-row blocks grown by the common system of culture 
alternated with 4-row blocks grown by the single-stalk system of 
culture. 
In section C there were three blocks of five rows each. The plants 
in the five rows of each block were spaced to 6, 9, 12, 18, and 24 inches 
apart, respectively. The blocks were thinned on three different dates, 
1See Bulletin 220 of the Bureau of Plant Industry, entitled “‘The Relation of Drought to Weevil 
Resistance in Cotton.” 
