DETAILED STUDY OF SOIL TYPICAL. OF EXTENSIVE AREAS. 31 
determinations were made. Yet these results show conclusively that 
in both good and poor soils there are large numbers of ammonifiers 
which are physiologically active if proper conditions are provided for 
them to develop. The relative differences in their ammonifying 
power and whether or not there are conditions in the soil to prevent 
their normal activities remain to be shown by further experiment. 
Denitrification is of two kinds: The reduction of nitrates to lower 
forms or transformation into organic form, and the complete breaking 
down of the nitrogenous substance with the evolution of free nitrogen 
as a gas. Either of these processes could be a source of infertility. 
Sy) 
ro) 
(S) 
1100 
=) 
=) 
fe) 
SS 
SN 
SEN 
Na 
TH 
ww 
x 
R : 
SS 
Fic. 20.—Diagram showing the ammonification of peptone in 15 days in samples of soil from plat 350 (good 
soil) and from plats 330 and 340 (poor soil), Truckee-Carson Experiment Farm. 
The evolution of free nitrogen was determined by measuring the 
nitrogen gas produced from peptone-nitrate solutions at intervals of 
7 and 15 days. The results are rather erratic, as is shown in Table 
VIII. 
TaBLe VIIIl.—Denitrification by samples of soil from plats 330, 540, and 350, Truckee- 
Carson Experiment Farm. 
Denitrification. | 
See f | Gas formed in— 
; | Depth of | Character 
soil. | | of soil. 
7 days. i5 days. | 
| | 
Inches. .| Per cent. | Per cent. | 
330 0-6 30 308, | eoor 
| 6-12 es 10 
12=18) Qi 5 
18-24 | 2 5) 
340 0-6 35 40 Do. 
6-12 40 40 
12-18 | 20 25 
18-24 | 30 40 | 
350 : 0-6 2 7 | Good. 
6-12 1 3 
12-18 | 1 5 
18-24 | 20 | 20 
211 
