22 
Colorado Experiment Station. 
rado far exceed the soils from the otheT regions cited; second, the 
degree of ammonifying efficiency manifested by our normal soils 
is about the same as that of other soils, with a slight difference in 
favor of the Colorado samples. 
1 he first four samples in 1 'able No. 6 represent four localities 
in the state and three distinct types of soil where nitrates are mak¬ 
ing their presence manifest by injury to apple trees. No. 17 came 
from the top of an adobe hill, and is as nearly raw land as can be 
found in Colorado, in fact, it might be classified more correctly as 
a weathered shale than as soil. The last three were obtained from 
widely separated districts, and may be considered normal arable 
soils so far as the presence of excessive nitrates and crop yields 
are concerned. The soil nubmers given in the above table correspond 
to the sample descriptions given in the preceding pages. 
1 he character of New Jersey soil No. 1 is not recorded in the 
text from which I have secured the analysis, but No. 2 is given as 
a silt loam. Calcium carbonate was added to the latter soil along 
with the cottonseed meal and linseed meal to neutralize any organic 
•acids that might be formed during ammonification. This may 
account for the close agreement between the New Jersey and Colo¬ 
rado results in the one case, since our soils contain an abundance 
of carbonate normally. 
Table No. 6. Ammonifying Efficiency of Colorado Soils Compared 
With Other Soils. 
Per 
cent, nitrogen 
recovered 
as ammonia in 
7 days from : 
Soil 
Character Cottonseed meal 
Dried blood 
Alfalfa meal 
Flaxseed meal 
Colorado 2 
Heavy clay 
42.31 
47.04 
12.78 
8.09 
Colorado 8 
Clay loam 
51.98 
47.98 
15.30 
1.12 
Colorado 14 
Clay loam 
47.73 
52.33 
16.56 
3.99 
Colorado 16 
Sandy loam 
47.10 
52.64 
13.69 
.21 
Colorado 17 
Raw adobe clay 
37.37 
23.67 
12.75 
2.87 
Colorado 10 
Sandy loam 
28.33 
23.57 
4.97 
8.14 
Colorado 18 
Gravelly clay 
28.02 
39.79 
2.83 
5.26, 
Colorado 29 
River bot. silt 
21.09 
25.08 
.73 
3.11 
New T. 1 (1) 
Unknown 
4.95 
16.74 
New J. 2 (2) 
Silt loam, limed 
41.18 
56.63 
46.06 
Iowa (3) 
Marshall loam 
29.82 
24.18 
Calif. (4) 
L. Sandy loam 
18.99 
N. Car. (5) 
Unknown 
3d.86 
No. 2069 
N. Car. 
Unknown 
22.06 
No. 1931 
'The California sample is described as a “light sandy loam free 
from alkali, from a walnut grove in Southern California—fairly 
well supplied with humus, owing to the careful system of green 
(1) . Marshall’s Microbiology, p. 254. The ammonia determinations were made after 
6 days 
(2) . Lipman, Brown and Owen. The availability of nitrogenous materials as 
measured by ammonification. Cent. f. Bakt.. Abt., II., Bd. 31, No. 1-4 p. 49, 1911. 
(3) . Brown, P. E. Some Bacteriological Effects of Liming. Research Bui. No. 2, 
Iowa Exp. Sta. 
(4) . L'pman Chas. B. Toxic Effects of “Alkali salts” in Soils on Soil Bacteria. I. 
Ammonification. Cent. f. Bakt., Abt. II., Bd. 32, No. 1-2, p. 58, 1911. Ammonia determi¬ 
nations made after 4 days. 
(5) . Stevens and Withers. Studies in Soil Bacteriology, II. Ammonification in soils 
and in solutions. Cent. f. Bakt., Abt. II., Bd. 23, No. 21-25 1909. 
