CHAPTER VIII 



FERTILIZERS, MANURES AND ROTATIONS FOR 

 COTTON 



THE problem of maintaining permanently the produc- 

 ing power of the soils in the cotton-belt involves, (1) such 

 a system of cropping as will provide these soils with an 

 abundance of organic matter and nitrogen, and (2) the 

 application of the two important plant-food materials, 

 phosphoric acid and potash, to those soils in which 

 these constituents are more or less deficient. In general, 

 the cotton farmer has neglected the first of these practices 

 and has greatly abused the second. In fact, he has learned 

 to rely, almost entirely, upon commercial fertilizers to 

 supply the nitrogen as well as the mineral foods where these 

 constituents are deficient. 



The fact that soils have rapidly decreased in productive- 

 ness following the continuous production of cotton has 

 led most cotton farmers to believe that cotton is a very 

 exhaustive crop. From the standpoint of the amount of 

 plant-food materials taken out of the soil this is not 

 true. 



89. Fertility removed by cotton. An acre of cotton 

 yielding 500 pounds of lint, 1000 pounds of seed and 2000 

 pounds of stalks will remove from the soil approximately 

 the following amounts of nitrogen, phosphoric acid, and 

 potash: 



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