COMMERCIAL FERTILIZERS 79 



Value of Crop Determines Rate of Fertilization. — Crops are divided 

 into two classes with reference to the use of commercial fertilizers. The 

 first class includes those crops having a comparatively low money value, 

 such as hay and the general grain crops. Because of the low money value 

 it is possible to apply only small amounts of fertilizer profitably. It is 

 also necessary that the crops use as large a proportion of the applied 

 material as possible. The cropping system should be arranged so as to 

 utilize the residues of previous applications. As a rule it is wise to pur- 

 chase very little nitrogen for such crops, since their needs can generally 

 be met by growing suitable legumes in the rotation. In the temperate 

 climate of the United States and Canada, east of the 100th meridian, red 

 clover is the crop best adapted for this purpose, although there are other 

 clovers and annual legumes that may meet local conditions better. In 

 the southern part of the United States cowpeas, soy beans, Lespedeza 

 clover, crimson clover and some other legumes are best suited for this 

 purpose. West of the Mississippi River alfalfa will pretty fully meet the 

 needs of the soil for nitrogen. Ordinarily it will be grown several years 

 in succession. 



Valuable Products Justify Heavy Fertilization. — The second class 

 of crops includes those having a high money value per acre and for which 

 large applications of high-grade fertilizers may be economically used. 

 Among such crops may be mentioned tobacco, cabbage, early peas, 

 spinach, asparagus and even early potatoes. Because of the high money 

 value of these crops a larger investment in fertilizers may be more than 

 paid for, even though the percentage increase in yield is no greater than 

 when fertilizers are applied to crops of low money value. In growing 

 early truck crops, especially when grown along the lower portion cf the 

 Atlantic seaboard or in the southern states, the truck farmer who can get 

 his product into the northern markets earliest is the one who receives 

 the fancy prices. Such markets call for products of high quality, and 

 quality in many cases is determined by the rate of growth. In such 

 crops as lettuce, radishes, spinach, etc., succulence and tenderness of the 

 product are essential. These qualities, together with earliness, are often 

 determined not only by the time of planting and the character of soil on 

 which the crops are grown, but also by the character of the fertilizer used. 

 We, therefore, find such farmers using fertilizers that are readily soluble 

 and well supplied with available nitrogen. Nitrogen tends to accelerate 

 vegetative growth and to give quality to early vegetables. It is not 

 unusual to find truck farmers applying as much as a ton per acre of a 

 high-grade fertilizer. The crop grown may use a comparatively small 

 portion of the constituents applied. This calls for a rotation of crops on 

 the part of such a farmer so that other and less valuable crops may follow 

 and be benefited by the residual effect of the fertilizer. 



A strict classification of crops into the two classes mentioned is 

 impossible. Conditions which would place a crop in one group in one 



