11 
materials except casein. As is well known, a wide range of organ- 
isms, including bacteria and fungi, have the power of splitting 
ammonia from organic materials. Some of these are aerobic, some 
anaerobic, and others facultative anaerobic. When anaerobic con- 
ditions are brought about, the formation of ammonia has usually 
been found to be considerably less than under aerobic conditions. 
SERIES V — AMMONIFICATION WITH EQUAL AMOUNTS OF NITROGENOUS 
AND NONNITROGENOUS MATERIALS. 
In order to make the conditions for bacterial action more nearly 
equal, the different materials were added so as to furnish equal 
amounts of nitrogen (132.9 milligrams), and the inequalities in the 
amounts of nonnitrogenous materials were balanced by the addi- 
tion of the proper amounts of cornstarch. One gram of calcium 
carbonate and 100-gram portions of the above soil were used. Opti- 
mum moisture conditions were provided and the same methods 
employed as in the previous series. 
Amount of ammonia formed, with equal amounts of nitrogenous and nonnitrogenous 
materials. 
[Average of 2 samples.] 
Period of incubation. 
Nitrogen as ammonia from — 
Casein 1.072 
gm., starch 
1.586 gm. 
Dried blood 
lgm., starch 
1.058 gm. 
Soy bean 
cake meal 
1.605 gm., 
starch 
1.053 gm. 
Cottonseed 
meal 2.606 
gm. , starch 
0.052 gm. 
Linseed 
meal 
2.658 gm. 
2 days 
4 days 
6 days 
9 days 
Per cent of total N converted into 
NH, 
Mg. 
31.0 
30.9 
35.8 
41.8 
Mg. 
0.3 
3.3 
10.4 
25.2 
Mg. 
4.4 
20.1 
33.5 
45.4 
Mg. 
10.3 
34.8 
42.6 
45.2 
Mg. 
2.4 
25.8 
36.2 
45.3 
31.4 
18.9 
34.1 
34.0 
34.1 
By comparing the above with Series III it will be seen that the addi- 
tion of starch materially influenced the accumulation of ammonia. 
By adding 1.586 grams of starch the ammonification of casein was 
reduced practically 50 per cent throughout the nine days. The effects 
on the ammonification of dried blood were still more marked. At 
the end of two days practically no ammonia had appeared and the 
depressing effect was observed throughout the experimental period; 
after nine days only 18.9 per cent of the nitrogen added as dried 
blood occurred in the form of ammonia. A similar, although less 
marked depressing effect, was observed with soy bean cake meal, 
but it must be remembered that 0.605 gram less starch was added 
than with the dried blood. The final yields of ammonia from soy 
