FERTILIZERS, ROTATIONS FOR COTTON 83 



the problem is to render this natural supply of potash 

 available to crops by good soil management, rather than 

 to depend upon potassic fertilizers. On the other hand, 

 there are extensive areas of soils, especially those of an 

 extremely sandy nature, that are very deficient in plant- 

 food. The plant-food materials should be returned to 

 these soils in amounts exceeding those in which they are 

 removed by crops, as there is considerable loss of these 

 materials as a result of leaching and erosion. 



COMMERCIAL FERTILIZERS FOR COTTON 



91. Nitrogen-supplying fertilizers. The two fertiliz- 

 ing materials supplying the greater part of the purchased 

 nitrogen for cotton soils are cotton-seed meal and sodium 

 nitrate. Other materials of secondary importance are 

 ammonium sulfate, dried blood, tankage, and cotton seed. 

 An important factor in determining which of the above 

 materials the cotton grower should buy is the relative 

 cost of the element nitrogen. In fact, the farmer should 

 secure the greater part of his nitrogen through the growth 

 of legumes and the production and use of farm manures. 



92. Sodium nitrate versus cotton-seed meal. Ex- 

 periments and farm experience have shown that on most 

 soils, when the materials are properly applied, a pound of 

 nitrogen will give equally good results when applied to 

 cotton in either sodium nitrate or cotton-seed meal. As 

 the form in which the nitrogen is contained differs in these 

 two fertilizers, correct practices as regards their applica- 

 tion differ somewhat. Sodium nitrate contains its nitro- 

 gen in the form of a soluble inorganic salt and for this 

 reason it is a quick acting fertilizer. It is not absorbed by 

 the soil in large quantities and is easily lost in the drainage 

 water. The nitrogen in cotton-seed meal is combined with 



