JOURNAL OF AfflOTIM RESEARCH 
DEPARTMENT OP AGRICULTURE 
Vol. V Washington, D. C., February 14, 1916 No. 20 
NITROGEN CONTENT OF THE HUMUS OF ARID SOILS 1 
By Frederick J. Ai/way, Chief, Division of Soils , Agricultural Experiment Station 
of the University of Minnesota , and Earl S. Bishop, Industrial Fellow, Mellon 
Institute 
HISTORICAL REVIEW 
One of the most generally recognized characteristics of arid soils 
(16, p. 163; 15, p. 415; 17, p. 72; 13, p. 147) 2 is the high content of 
nitrogen contained in their humus, the matikre noire of Grandeau (6, p. 
148). 
Attention was first called to this by Hilgard and Jaffa (10), who 
stated (p. 69): 
It thus appears that on the average the humus of the arid soils contains three times 
as much nitrogen as that of the humid; that in extreme cases the difference goes as 
high as 6 to 1. 
It is somewhat remarkable that so few other investigators have made 
any attempt to test this generalization in the case of the soils from the 
arid portions of either* this or any of the other continents. 
Fulmer (5) determined the humus nitrogen in 53 soils from Wash¬ 
ington, a State with winter rains and summer droughts. In the case of 
two soils from Skagit County, which has an annual precipitation of 
about 46 inches, he found 10.46 and 12.04 P er cent, respectively, of 
nitrogen in the humus. 
Nabokich (14, p. 339) reports six samples from Bessarabia with from 
11.1 to 18.9 per cent of nitrogen in the humus. It seems probable, how¬ 
ever, that he has confused the use of the term “humus” as employed on 
the continent of Europe (organic matter of the soil as determined by com¬ 
bustion with copper oxid) with the sense in which it is generally used in 
this country. However, he makes a direct comparison of the Danubian 
soils with those of California, as follows: 
In contrast with the soils of the dry steppes of southern Russia, the humus of the 
borders of the Danube is quite as rich in nitrogen as that of the soils of the steppes of 
California and Transcaucasia. The alluviums of the Danube are even richer than those 
of the Arax. 3 
1 The work reported in this paper was carried out in 1911 at the Nebraska Agricultural Experiment 
Station, where the authors were, respectively, Chemist and Assistant in Chemistry. 
2 Reference is made by number to “ Literature cited," p. 915-916. 
8 Author’s translation (14, p. 339). 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
eg 
(w) 
VoL V. No. 20 
Feb. 14; 1916 
Minn.—8 
