68 COTTON CULTURE 



Fertilizers of the second class comprise lime, gypsum 

 (plaster), and common salt, and are sometimes called 

 "stimulant fertilizers.'' They tend to make rapidly avail- 

 able the stores of potash, phosphoric acid, and nitrogen 

 naturally present in the soil. When stimulant fertilizers 

 are used exclusively for a term of years, the soil each year 

 loses potash, phosphoric acid, and nitrogen, which are not 

 replaced. The inevitable result of such treatment must 



No Fertilizer. Yield, 540 Ibs. Seed Cotton per acre. 



RESULTS OF FERTILIZER TEST BY C. L. FREELING, BEEBE ARK. 



naturally be the exhaustion of these important food con- 

 stituents from the soil. 



True fertilizers contain forms of plant food, which con- 

 tribute directly to the growth and substance of plants. 

 Such materials may contain potash, or phosphoric acid 

 compounds or nitrogenous substances; or any two, or all 



