32 Fertilizers 



increase, and the only other source is an artificial supply, 

 or commercial fertilizers. For the special crops already 

 described, the natural manures of both farm and city 

 are not only not sufficient, but, because of their character 

 and composition, are not well adapted to meet economi- 

 cally the entire demands of the plants. In the first place, 

 they are bulky, and thus expensive to handle. In the 

 second place, the fertility elements contained in them are 

 not in good proportion; they are, as a rule, poor in the 

 mineral elements and rich in nitrogen, and their use in 

 sufficient amounts to meet the needs of the plant for the 

 mineral elements results in a waste of the nitrogen. Third, 

 the constituents contained in them are not in sufficiently 

 active forms to provide for a rapid and continuous growth 

 without an excessive application, which frequently results 

 in a serious waste not only of the nitrogen, as already indi- 

 cated, but, in the case of many crops, an abnormal growth 

 of vine or stalks, which may seriously injure the market- 

 able quality of the crops. For many crops, economical 

 production requires that the natural manures be supple- 

 mented by artificial supplies, by means of which the form 

 and amount of the individual constituent can be regu- 

 lated to meet the needs of the various plants. 



The growing importance of fruit-growing. 



In fruit-culture, an industry of growing importance, 

 it has been found that soils in their natural condition, 

 while they may be well adapted in other respects, that 

 is, possess a suitable physical character for the growth 

 of this class of crops, contain insufficient amounts of 

 the mineral constituents which are required in order 

 that continuous and large crops of perfect fruit may 

 be secured. To supply this deficiency farmyard manure 



