Cotton Growing in Arizona 269 



THINNING 



The thinning of cotton is a question on which the best cotton grow- 

 ers hold widely differing opinions. We believe that the distance to 

 which cotton plants are to be thinned should be governed largely by 

 the soil. Heavy, rich land will stand thick plantings of cotton. Thin, 

 light land should have cotton spaced relatively far apart. This thin 

 planting, however, should not be carried to such an extreme that the 

 land will not be utilized to its full capacity to produce. With heavy 

 rich ground some cotton growers prefer that the plants be from six 

 to ten inches apart. A few growers will prefer even less space than 

 this. The average cotton grower with typical cotton land of the Salt 

 River Valley will space his cotton from 12 to 18 inches apart in the 

 row, with rows 3^^ feet apart. On thin poor land it may be advisable 

 to increase the spacing to 24 or 30 inches. The purpose of thinning 

 cotton is so to space the plants that they may have light, air, moisture, 

 and plant food in such proportions that they will produce the maxi- 

 mum number of matured bolls per acre. Cotton given too much space 

 is very likely to produce a large, coarse plant, from which the branches 

 may be broken in the fall by heavy winds. Cotton given a reasonable 

 spacing can stand more drying or more severe conditions and still re- 

 cover than cotton closely spaced. American Egyptian long-staple cot- 

 ton should be thinned on the sandy light soils when the plants are from 

 four to eight inches high, and on the heavy rich soils when the plants 

 are from eight to twelve inches high. On the extremely rich soils 

 thinning can be delayed till the plants are fourteen to sixteen inches 

 high. 



Time of thinning has a great deal to do with the control of vege- 

 tative branches. The development of vegetative branches is undesir- 

 able in American Egyptian cotton. Early thinning encourages their 

 development while late thinning discourages their development. 



CULTIVATION 



The cultivation of cotton should begin as soon as the plants are 

 through the ground well enough to mark the row, and be continued 

 every 10 to 15 days till the plants are too large to permit the use of a 

 regular cultivator. Sometimes the cultivation can be continued by the 

 use of a one-horse cultivator, especially in the wider spaced rows and 

 on heavy soils that tend to bake. Early cultivation checks evapora- 

 tion, warms the soil, and will kill weeds and grass at the stage at which 

 they are most easily destroyed. It will also eliminate much hand work 

 or hoeing. For the most part the early cultivations may be compara- 



