320 SOUTHERN FIELD CROPS 



287. Effects of commercial fertilizers on the soil. 

 Commercial fertilizers are, on the whole, profitable, in 

 spite of many misfits between soil, crop, and fertilizer. 

 Indeed, in a large part of the cotton-belt they are indis- 

 pensable. The profits from their use will increase with a 

 more general knowledge of agricultural principles. Com- 

 mercial fertilizers have been occasionally charged with 

 being largely responsible for the impoverished conditions 

 of the cotton fields and the scant profits of the cotton 

 grower. This is not correct. They do not in themselves 

 exhaust the soil. Reliance upon fertilizers alone may 

 cause a farmer to keep his land too long in cotton, instead 

 of letting cotton alternate with soil-improving crops, such 

 as cowpeas. The exhaustion of the fertility of the cotton 

 fields is due chiefly to leaching, washing, and loss of vege- 

 table matter as the result of continuous clean cultivation. 



For the scant profits too often secured in the culture 

 of cotton, the chief causes are impoverished soil, purchased 

 supplies, unintelligent use of fertilizers, scarcity of capital, 

 deficiency of labor-saving machinery, unsatisfactory labor 

 conditions, and the failure to master the principles which 

 underlie a rational system of farming. What should be 

 condemned is not the use, but the abuse, or purposeless 

 use, of commercial fertilizers. 



288. Most popular factory-mixed fertilizers. The use 

 of ammoniated guanos, that is, complete fertilizers con- 

 taining nitrogen, is more general among cotton farmers 

 than the use of chemicals bought separately and mixed 

 on the farm. The most extensively used form of com- 

 plete ready-mixed guano contains about 1.65 per cent of 

 nitrogen (equal to 2 per cent of ammonia), 10 per cent of 



