462 MISCELLANEOUS FARM SUBJECTS 



APPLICATION OF FERTILIZERS. 



Crops may be divided into two classes with reference to the ap- 

 plication of fertilizers. The first class includes those crops which 

 have a comparatively low value per acre and to which large applica- 

 tions of fertilizer cannot be made without costing a considerable pro- 

 portion of the value of the crop. For these crops the plant food in the 

 soil must be utilized as fully as possible and the application of fer- 

 tilizer must be made as skillfully as possible. The cropping system 

 should be arranged so as to utilize economically the residues from the 

 previous application. 



As a general rule, it may be said that it is not profitable to pur- 

 chase all the nitrogen needed by crops of this character. The fer- 

 tility of the soil must be maintained with nitrogen secured from the 

 air, and nitrogenous fertilizers should be used only to supplement 

 the supply secured in this way. This involves a rotation of crops, 

 in which nitrogen-gathering plants are grown cowpeas, vetch, bur 

 clover, peanuts, etc. 



The second class of crops includes those which have a high value 

 per acre and for which even large applications of fertilizers may cost 

 only a comparatively small proportion of the value of the crop. 

 These crops, as a general rule, must be grow r n as rapidly as possible, 

 and they require abundant supplies of plant food. Although atten- 

 tion should be paid to the needs of the soil, it is possible to make such 

 heavy applications of plant food that the supply in the soil may be 

 more or less disregarded. These crops can, of course, be followed by 

 other crops to utilize the large residues of plant food. 



It is not possible to make a strict classification of crops under 

 these two groups, for conditions which place a crop in one group in 

 one locality may place it in another group in another locality. A 

 high price for a crop, due to market conditions, may change it from 

 the first to the second group. Cotton, corn, rice, and alfalfa can be 

 classed with crops of low acre value, and onions, sweet potatoes, to- 

 matoes, melons, asparagus and similar crops with those of high acre 

 value. 



If fertilizers are used, the following general rule should govern : 

 On rich lands use mainly fertilizers that will stimulate the fruit and 

 not the stalk growth. On lighter lands use more of the elements to 

 force growth, combined with others which will mature the fruit. 



High-grade 14 per cent acid phosphate may be considered a 

 basis for increasing fruit and hastening maturity of crops. Even on 

 the richest land it has been demonstrated that a small percentage of 

 nitrogen added to the acid phosphate gives better results. Use three 

 parts of acid phosphate and one part of cotton-seed meal for cotton. 



A mixture of one part of cotton-seed meal to two parts of high- 

 grade acid phosphate will greatly increase the growing condition and 

 will be better for medium soils. Air-slaked lime is of value for use 

 on stiff or gummy soils to loosen them up, permit the air to enter, 

 and prevent a sour condition of such soils when too wet. On thin or 

 impoverished soils equal quantities of cotton-seed meal and acid phos- 

 phate can be used to advantage. In case the foregoing can not be 



