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, 



1 See Bulletin 220 of the Bureau of Plant Industry, entitled "The Relation of Drought to Weevil 

 Resistance in Cotton." 



