COTTON FERTILIZERS 317 



phosphoric acid but only a quarter of the potash found 

 in the entire plant. The composition of a plant or of the 

 part removed from the soil is not a guide to the correct 

 fertilization of that plant ; yet it is well to know that the 

 lint and seed together in a crop of 300 pounds of lint re- 

 moved plant-food which at ordinary prices would be 

 worth in commercial fertilizers about $3.75. Of this 

 amount, the fertilizer constituents in the lint alone are 

 worth only 25 to 30 cents. Indeed, no other ordinary 

 crop makes such slight demands on fertility as does the 

 cotton fiber. If the seed and all other parts of the plant 

 except the lint were returned to the soil, there would be 

 no reductions in fertility except those due to extraneous 

 influences, such as surface washing, loss of vegetable 

 matter (Fig. 146) through clean cultivation, and loss of 

 nitrates from the soil in the drainage water. 



The seed and lint together, in the case of a crop of 300 

 pounds of lint, make a draft on soil fertility that is about 

 the same as would be removed by the grain alone in a crop 

 of 25 bushels of corn or of 35 bushels of oats. 



283. Amounts of fertilizer required to take the place of 

 plant-food removed by lint and seed. Three hundred 

 pounds of cotton-seed meal and twenty-seven pounds 

 of kainit would furnish all the fertilizer constituents re- 

 moved from the soil by a crop of 300 pounds of lint with 

 its accompanying seed; this quantity of cotton-seed 

 meal would supply not only the nitrogen, but all of the 

 necessary phosphoric acid. If the nitrogen were drawn 

 wholly from the decay of leguminous plants and no cotton- 

 seed meal were applied, 51 pounds of acid phosphate, con- 

 taining 14 per cent of available phosphoric acid, would 



