344 T11E l''ORAGIi AND FIBER CROPS IN AMERICA 



The lint not only contains small percentages of nitrogen and 

 phosphoric acid, but the weight of lint obtained per acre is small 

 compared to the weight of most cultivated crops. The seed con- 

 tains relatively high quantities of both substances, and there are 

 rather more than two pounds of seed for each pound of lint. 

 The seed, however, is not injured as a fertilizer by the extrac- 

 tion of the oil. If therefore all the plants except the lint and the 

 oil is returned to the soil, the loss of these elements from the 

 sale of the products is trifling. 



The soil loses fertility by the oxidation of the vegetable 

 matter in the soil during the summer months, and the wash- 

 ing away of the material thus made soluble during the winter 

 months. The comparative bareness of the soil and the heavy 

 rainfall favor erosion at all seasons of the year, causing the 

 removal of quantities of surface soil. Formerly when land and 

 labor were cheap, old cotton fields were abandoned when no lon- 

 ger productive, and new lands were brought under cultivation. 



The cotton states have comparatively few domestic animals, 

 and the climatic conditions do not favor the collection and pres- 

 ervation of manure. While manure is recognized to be of value 

 it does not enter largely into the production of cotton. Since 

 lands and labor have become dearer commercial fertilizers have 

 entered largely into its production. More recently a greater 

 diversity of crops, especially the introduction of the cowpea, has 

 obtained. Such diversification is a factor of great importance in 

 combating fungous diseases and insect enemies. 



438. Rotation. The two main soil problems connected with 

 the growing of cotton are the preventing of the bodily removal 

 of the soil through erosion and the securing such a rotation of 

 crops as will restore the organic matter to soils depleted by 

 long-continued clean cultivation in one crop. 1 



Notwithstanding that a well-ordered system of rotation of crops 



1 Report of the Secretary of Agriculture; in U. S. Dept. Agr. Yearbook 

 1905, p. 69. 



