FERTILIZERS 221 



larger total yields will usually result from soils which are sufficiently 

 fertile to produce a well-matured crop but which are not rich enough 

 to prolong past a normal maturing period the active growth of the 

 plant. 



In the northern area of the cotton belt it is sometimes better 

 even to balance a deficiency in soil fertility by the addition of com- 

 mercial fertilizer than to choose a rich, moist bottom-land which 

 will produce a heavy vegetative growth at the expense of a matured 

 fruitage. 



In the southern area, however, the most fertile soils are prefer- 

 able, for here the growing season is of a sufficient length to allow the 

 maturation of a larger proportion of the fruit than is usually pos- 

 sible in the shorter season of the more northerly area. With the 

 advantage of a longer growing season, during which most of the 

 fruit set by the plant is matured, the total yield is somewhat pro- 

 portional to the degree of soil fertility. 



Soils for Sea Island Cotton. The Sea Island cotton, unlike the 

 upland variety, is not adapted to widely different soils. It is best 

 suited by light, fine, sandy soils, which contain but small propor- 

 tions of clay and silt. Soils of this character retain little moisture, 

 and in that respect they are quite different from the best type of 

 soils adapted to the upland cotton. In respect to its need of soil 

 fertility, however, Sea Island cotton is like the upland variety. It 

 is best adapted to soils of medium fertility which tend to produce a 

 well-matured crop rather than to stimulate an extremely large 

 vegetative growth. 



Fertilizers. The enormous increase since 1865 in the produc- 

 tion of cotton in the United States is due chiefly to the use of com- 

 mercial fertilizers. With the aid of fertilizers a large area of de- 

 pleted soils in the cotton belt has been returned to a state of 

 profitable productiveness. 



Effect of Fertilizers. When used for the production of cotton, 

 the effect of fertilizers is twofold (1) they increase the growth 

 of the plant, and (2) they stimulate the plant to an early ma- 

 turity. 



By the influence of fertilizers in shortening the period of active 

 growth of the plant, the northern limit of the area in which cotton 



