326 FIELD CROPS FOR THE COTTON-BELT 



An excellent three-year rotation adapted to a large part 

 of the wheat-growing area of the cotton-belt is: First 

 year cotton ; second year corn with cowpeas between 

 the rows; third year wheat followed by cowpeas. 



The Kentucky Station has adopted the following rota- 

 tion : First year corn followed by rye for a winter cover- 

 crop; second year soy-beans or cowpeas; third year 

 wheat; fourth year clover. 



400. Fertilizers. Fertilizers, if necessary for wheat, 

 are most profitable when the crop is grown in a rotation 

 that keeps the soil well supplied with decayed vegetable 

 matter. On much of the waxy lime lands of Texas and 

 Alabama direct fertilization of wheat is unnecessary. 

 These soils usually contain an abundance of mineral mat- 

 ter, and the indirect method of fertilizing by growing 

 wheat in a rotation that supplies the soil with organic mat- 

 ter renders this mineral matter available and supplies an 

 abundance of nitrogen. The red clay and valley soils of 

 the Piedmont region are generally well supplied with 

 potash but are rather deficient in phosphoric acid. The 

 amount of nitrogen in these soils varies, of course, with the 

 amount of organic matter present. Wheat following a 

 soil-improving crop on these Piedmont soils will usually 

 need the application of a phosphatic fertilizer only. In the 

 older wheat-growing regions of the cotton-belt, particularly 

 when the wheat is grown on land that has been under 

 cultivation for many years, it is customary to fertilize 

 rather heavily. On such soils liberal fertilization is often 

 profitable, but numerous experiments have clearly demon- 

 strated that the yield does not increase proportionately 

 as the quantity of fertilizer is increased. Care should 

 be exercised to see that the profitable limit is not ex- 

 ceeded. 



