COTTON FERTILIZERS 329 



of cotton-seed meal and hulls was fed to dairy cows, and 

 every particle of the resulting manure was returned to 

 the soil as fertilizer for cotton. An exactly similar amount 

 of cotton-seed meal and hulls was applied directly as 

 fertilizer for cotton. The yield of cotton was much greater 

 where the manure was used. This was probably due in 

 part to the quicker decay of the manure than of the meal 

 and hulls. 



301. A rational system of fertilization with nitrogen. 

 Considering permanent effect, as well as influence on 

 the crop immediately following, the cowpea and other 

 leguminous plants must be ranked as a cheaper source of 

 nitrogen than is any nitrogenous material which may be 

 bought as commercial fertilizers. The aim of the cotton 

 farmer should be to grow such areas of legumes as will 

 enable him to dispense with the purchase of nitrogenous 

 fertilizers for cotton, using the funds thus saved to pur- 

 chase increased amounts of phosphates or other necessary 

 non-nitrogenous fertilizers. The money that would have 

 been necessary to purchase one pound of nitrogen will buy 

 about three pounds of phosphoric acid, or of potash, which 

 larger purchases of phosphate and potash will enable the 

 farmer to grow heavier crops of legumes. And heavier 

 crops of legumes trap larger amounts of otherwise un- 

 available atmospheric nitrogen and result in further soil 

 enrichment and larger yields of cotton. 



PHOSPHATIC FERTILIZERS 



302. Different kinds of phosphate. While there are 

 a number of forms in which the farmer may obtain phos- 

 phoric acid, the one that is almost universally employed 



