CHAPTER X 



COMMERCIAL FERTILIZERS 1 



There are some farms on which neither the manure of cattle nor of birds 

 is to be got ; however, even in such places, he is a slothful husbandman that 

 has no manure. COLUMELLA 



109. Why we need commercial fertilizers. Under the best 

 systems of farming only a part of the food taken from the soil 

 by crops is returned in manure. There is a constant stream of 

 soil fertility flowing from the farm to the city in breadstuffs, 

 meats, and fruits that are sent there to feed the people. In the 

 city the waste from these foodstuffs is a nuisance. On the land 

 it is a blessing. For centuries the Chinese farmers have gathered 

 this waste and applied it to the land. We have turned to other 

 sources, such as the phosphate and potash mines and the by- 

 products of manufacturing, for the plant food which the farm 

 manures do not supply. These mined or manufactured fertilizers, 

 such as nitrate of soda, acid phosphate, and bone meal, are called 

 commercial fertilizers to distinguish them from natural fertilizers 

 like barnyard manure or green manure. 



110. Extent to which commercial fertilizers are used. The 

 use of commercial fertilizers in the United States is rapidly 

 increasing. In 1889 the farmers spent $28,000,000 for ferti- 

 lizers; 2 in 1899, $55,000,000; in 1909, $112,000,000. The 



1 In localities where commercial fertilizers are not used, it is suggested that 

 this chapter be omitted or be considered briefly. 



2 United States census reports. 



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