BULLETIN 
No. 37. 
Contribution from the Bureau of Soils, Milton Whitney, Chief. 
December 8, 1913. 
NITROGENOUS FERTILIZERS OBTAINABLE IN THE UNITED 
STATES. 
By 
J. W. TURRENTINE, 
Scientist in Soil Laboratory Investigations. 
INTRODUCTION. 
Present agricultural practice requires that nitrogenous matter be 
supplied to the soil supporting crop growth. At one time it was the 
belief that all the nitrogen found in the substance of the plant had its 
origin in that added to the soil as a fertilizer. Now, however, it is 
definitely known that this is by no means true in the case of certain 
types of plants and that the uncombined nitrogen of the atmosphere 
is made available for plant metabolism through the instrumentality 
of lower organisms inhabiting the soil. The marked accumulation 
of nitrates in certain soils of Colorado has been explained on the basis 
of the bacterial fixation of atmospheric nitrogen. 1 Nitrogen com- 
bined as nitrate of soda occurs naturally in the arid plateau region 
of Chile. It also occurs in certain of the rainless portions of the 
United States. In this country, however, it occurs as so small a 
proportion of its carrier that its extraction therefrom under present 
conditions is commercially impracticable. 2 Aside from this occur- 
rence, combined nitrogen is found in nature only in the complex 
compounds constituting the organisms of plants and animals or 
arising from the decomposition of these. In small amounts it is found 
in the soil in the form of certain organic compounds, 3 some of which 
are toxic in their action on growing plants, and some beneficial. 
The nitrogenous compounds comprising animal and vegetable 
tissues constitute the principal foods for man and animals. In gen- 
eral it is true, therefore, that only in those instances where their 
occurrence is such as to preclude their ready marketing or where por- 
tions of them for one reason or another are unfit for food, are they 
i Headden, Colo., Agr. Expt. Sta., Bulls. Nos. 155 and 160. 
2 Free, Report of a Reconnoissance of the Lyon Nitrate Prospect near Queen, New Mexico, Circ. No. 62 
Bureau of Soils, U. S. Dept. Agr.; Gale, U. S. Geol. Survey, Bull. 523, 1912. 
3 Bulls. Nos. 53, 70, 74, 77. 83, 87, Bureau of Soils, U. S. Dept. of Agr. 
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