BULLETIN OF THE 



eMIMOFAfflOM 



No. 158 



Contribution from the Bureau of Soils, Milton Whitney, Chief 

 November 10, 1914. 



(PROFESSIONAL PAPER.) 



THE NITROGEN OF PROCESSED FERTILIZERS. 



By Elbert C. Lathrop, 

 Scientist in Soil Fertility Investigations. 



INTRODUCTION. 



Organic compounds have lately taken on a deeper significance in 

 their relation to the complex problems of the soil and of crop produc- 

 tion, for not only do they affect the physical conditions and chemical 

 reactions of the soil but they also have been shown to be directly con- 

 nected with fertility or infertility, some of them being essentially bene- 

 ficial to the growth of plants, while others are distinctly harmful. 

 Of the organic compounds thus far isolated from soils, a large number 

 contain nitrogen, and of these nitrogenous substances, some have 

 been found rather widely distributed in soils varying as to location, 

 climate, methods of cropping, etc. These nitrogenous compounds 

 occur either as plant constituents or arise from the decomposition of 

 plant or animal protein, brought about by the various biological and 

 biochemical agents in the soil. Not only compounds of this class 

 found in soils but also many other protein decomposition products 

 have been studied, both alone and in conjunction with the three fer- 

 tilizer elements, in respect to their action on plant growth, and they 

 have been shown in a number of cases to exert a beneficial influence; 

 furthermore, these complex compounds are available for use by the 

 plant without first being changed by chemical or biochemical means 

 into ammonia and then to nitrates. 1 



That these facts have an immense practical bearing on fertilizers 

 and the fertilizer industry, both from the standpoint of the producer 

 and of the consumer, is at once obvious. The old high-grade nitrog- 



1 A Beneficial Organic Constituent of Soils: Creatinine. By Oswald Schreiner, E. C. Shorey, M. X. 

 Sullivan, and J. J. Skinner. Bui. 83, Bur. Soils, U. S. Dept. Agr., 1911. 



Nitrogenous Soil Constituents and Their Bearing on Soil Fertility. By Oswald Schreiner and J. J. 

 Skinner, Bui. 87, Bureau of Soils, U. S. Dept. Agr., 1912. 



This investigation is a contribution to the knowledge of the nature of the changes brought about in the 

 manufacture of some of the processed fertilizers, and of ihe character and availability of such processed goods 

 in mixed fertilizers when used in farm practice. 



63138°— Bull. 158—14 1 



