THE ORGANIC NITROGEN OF HAWAIIAN SOILS. 
INTRODUCTION. 
The greater part of soil nitrogen may reasonably be assumed to have 
been bound up at one time or another in protein combinations, since 
the nitrogen in the main has been derived from vegetable sources. 
Limited amounts of other nitrogen bodies, such as alkaloids, etc., 
also find their way into soils, but the nitrogen from such compounds 
could hardly be expected to amount to more than a small percentage 
of the total nitrogen present. The chemistry of soil nitrogen and the 
changes that it undergoes, therefore, must be largely those of plant 
proteins, brought about under complex and indeed extremely varia- 
ble conditions. A great host of organisms inhabiting soils are asso- 
ciated with the transformations of the organic nitrogen bodies, and 
the conditions and environment in which the organisms function 
not only materially alter the rates of their action but also determine 
largely what the end products shall be. The presence of various 
chemical substances, both organic and inorganic, the acidity or 
alkalinity, and the degree of porosity of the soil, all exert important 
influences on the activity of soil organisms. 
During the past few years considerable study has been devoted 
to the nitrogen compounds of the soil. In 1905-6, Shorey, 1 while 
chemist at this station, applied to a coffee soil from the island of 
Hawaii the methods formerly used in the study of protein, and thus 
determined the amounts of basic, nonbasic, ammonia nitrogen, etc., 
split off by means of boiling acids. In connection with his studies 
a pyridin derivative, picolin carboxylic acid, was isolated and identi- 
fied, this being the first definite organic nitrogen compound to be 
isolated from a soil. Recently a number of other studies on soil 
nitrogen have been reported. 2 
The researches previously made on this subject naturally divide 
themselves into two classes, as indicated by the work of Shorey. 
First, a study of the individual compounds that occur in natural 
soils; second, a study of the products formed by acid hydrolysis. 
The extensive researches of Schreiner, Shorey, 3 and their associates 
i Hawaii Sta. Rpt. 1906, pp. 87-89. 
» Jodidi, Michigan Sta. Tech. Bui. 4 (1909); Iowa Sta. Research Buls. land.3 (1911); Robinson, Michigan 
Sta. Tech. Bui. 7(1911); Lathrop and Brown, Pennsylvania Sta. Rpt. 1910, pp. 118-120; Jour. Indus, and 
En-in. (hem., 3 (1911), pp. 657-660. 
» U. S. Dept. Agr., Bur. Soils Bute. 47, S3, 71, B0, 87, 8! 
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