8 BULLETIN 1153, U. S. DEPARTMENT OF AGRICULTURE. 



duction, if not the largest production, of cotton under the San An- 

 tonio conditions, taking account of the many dry seasons when lack 

 of moisture instead of weevil damage is the limiting factor. 



The danger in dry seasons is that the plants will not grow large 

 enough to produce a crop, or that the crop may be lost if the plants 

 are so severely checked by drought that the buds or young bolls 

 are aborted. In dry seasons small plants in widely spaced rows have 

 the best prospect of securing moisture enough to reach the fruiting 

 stage, of avoiding serious checks, and of taking full advantage of 

 any favorable conditions that may occur. No doubt the best or safest 

 spacing might depend somewhat upon the nature and water-holding 

 capacity of the soil, but tentative experiments in previous dry sea- 

 sons at San Antonio indicated that about the same yield of cotton 

 per acre may be obtained With rows as much as 5 or 6 feet apart as 

 with rows 3 feet apart. The results were not consistent in other 

 years, and a wider range of experiments will be necessary to deter- 

 mine the facts. Some of the experiments were made with 6-inch 

 spacing, but the thinning was done later than would be advisable 

 if the plants were to be left still closer together with the rows wider 

 apart, Little or no thinning might be necessary if the stands were 

 not too thick. 



If favorable conditions could be assured in the early fruiting stage, 

 close spacing of the rows as well as of the plants in the rows might 

 give the largest yields, as some experiments show. But if weevils 

 survived the winter in large numbers and destroyed the early buds, 

 there could be little prospect of a crop later in the season, since with 

 the rows close together the ground is soon covered and shaded, and 

 the weevils ma} 7 continue to breed even in dry weather. 



Cutting out alternate rows would be a way to get more exposure, 

 if early-season conditions proved unfavorable or the weevils were so 

 numerous that an early crop could not be set. If late-season con- 

 ditions, like those of 1921, could be assured, cutting out the alternate 

 rows might be a practical measure, even with rows as far apart as 

 4 feet, but might give no advantage if wet weather continued late 

 in the season. 



At San Antonio the largest yields have been obtained in some 

 seasons with rows only 3 feet apart, but it is recognized that this 

 result would depend upon favorable early-season conditions, which 

 are by no means assured in southern Texas. In some years the 

 weevils are very abundant early in the season, and the setting of a 

 crop has often depended very definitely upon a period of dry 

 weather to hold the weevils in check. With the rows close together 

 the condition of continuous shading of the ground would be reached 

 earlier in the season, and there would be less chance of the weevils 

 being checked by periods of dry weather. If the conditions of boll- 

 weevil cotton can be avoided, the plants may be able to take advan- 

 tage of favorable periods of dry weather to set a crop, even late in 

 the season, as shown by the facts already stated. The results of a 

 single season are not to be taken as an index of the best course to be 

 followed as a general rule. An ideal system would make it possible 

 to take full advantage of favorable conditions at any stage in a 

 region of very variable weather like southern Texas. 



