COTTON SOILS AND CLIM'ATIC ADAPTATIONS 77 



-from minor setbacks. Nevertheless, such important cli- 

 matic factors as the length of the growing season, tem- 

 perature, sunshine, and the amount and distribution of 

 the raiafall are directly related to the normal growth and 

 fruiting of potton. 



86. Length of growing season. — The time required 

 for the full development of cotton is 190 to 200 days from 

 planting to harvest. In fact, the maximum yields are 

 produced in sections where the growing season exceeds 

 200 days. By examining Fig. 16, it will be noticed that the 

 length of the growing season in different portions of the 

 cotton-belt varies from 190 to 200 days in the northern- 

 most part to 300 days in the extreme southern hmit.. The 

 present tendency is to develop early maturing cottons to 

 avoid the injury from the boll-weevil. 



87. Amotint and distribution of the rainfall. — Pre- 

 cipitation is a very prominent factor in the development 

 of the cotton plant. Diu-ing April, at which time the 

 greater portion of the cotton crop is planted, Hght but 

 frequent showers are desired. The presence of excessive 

 moisture in the soil at this time causes the seed to decay 

 rather than germinate. On the other hand, an abundance 

 of capillary water must be present or the seedlings will 

 not secure the proper nourishment, the soil will bake, 

 and a poor stand will result. 



If the seed-bed for cotton has been properly prepared, 

 thus insuring the presence of a rather large amount of 

 available water in the soil at planting time, hght but well 

 distributed showers during the months of April, May, and 

 June give best result. This permits the roots to sink deep 

 into the soil, enabhng the plants to better withstand the 

 dry periods of late summer. A wet spring causes the rapid 

 development of surface roots to the sacrifice of the deeper 



