Mar. 1,1925 
Effect of Sulphur and Gypsum on Palouse Silt Loam 459 
EFFECT OF SULPHUR AND GYPSUM ON 
SOIL NITROGEN 
The data showing the effect of sul¬ 
phur and gypsum* on nitrogen in the 
soil and on nitrification are found in 
Table VII. 
It should be remembered that the 
nitrogen which leached through the 
soils during December represents the 
accumulation of nitrates during the 
summer and fall of 1922, for there had 
been no rains sufficient to leach the 
soil previous to this time. No effect 
was noticed for the treatments during 
December. All of the remaining data 
indicate that the different treatments 
caused a slight depressing effect on 
nitrification. It is difficult to account 
for the relatively small amount of 
nitrates present in the leachings and 
water extracts from the soils in ex¬ 
periment 2. Possibly it was due to 
the utilization^ of nitrates by the 
nitrogen-assimilating organisms, or to 
the extremely small quantity of water- 
soluble phosphorus contained in this 
soil. McHargue and Peter 8 in their 
study of the removal of mineral plant 
food by natural drainage waters found 
that a high phosphorus content of soils 
accelerates the action of the nitrifying 
organisms. 
EFFECT OF SULPHUR AND GYPSUM ^ON 
PHOSPHORUS 
Analyses were made for phosphorus 
in the drainage water and leachings 
obtained from the soils in both experi¬ 
ments, but the amounts obtained were 
so small as to be well within the limit of 
error for this determination. These 
results are therefore omitted from the 
discussion. Most soils have shown the 
capacity to, retain phosphorus com¬ 
pounds in the surface area, and 
usually only traces appear in the 
drainage. 
Table VII .—Amount of nitrogen in drainage water , teachings, and soil extracts 
Pot 
No. 
Treatment (pounds 
per acre) 
Experiment 1 (field pots)—nitrogen in pounds per 
2,000,000 pounds of soil - 
Experiment 2 (green¬ 
house pots)—nitrogen 
in pounds per 2,000,000 
pounds of soil 
De¬ 
cem¬ 
ber 
Jan¬ 
uary 
and 
Feb¬ 
ruary 
March 
and 
June 
Total 
for five 
months 
Soil 
' ex¬ 
tracts 
Total 
water- 
soluble 
nitro¬ 
gen 
Leach¬ 
ings 
Soil 
ex¬ 
tracts 
Total 
water- 
soluble 
nitro¬ 
gen 
1 
Control. 
48.7 
29.2 
29.2 
107.1 
79.2 
186.3 
24.8 
8.4 
33.2 
2 
.do.. 
57.1 
12.0 
66.6 
135.7 
88.5 
224.2 
27.8 
9.8 
37.6 
Average.. 
52.9 
20.6 
47.9 
121.4 
83.8 
205.2 
26.3 
9.1 
35.4 
3 
Uninoculated sul- 
- 
1 
phur 186.. 
58.3 
18.6 
14.6 
91.5 
55.9 
147.4 
21.1 
8.1 
29.2 
- 4 
.do._.. 
54.5 
15.0 
15.0 
84.5 
51.2 
135.7 
23.7 
7.3 
31.0 
Average_ 
56.4 
46.8 
14.8 
88.0 
53.5 
141.5 
22.4 
7.7 
30.1 
5 
Inoculated sulphur 
9 
189——.—_ 
59.3 
15.9 
16.0 
91.2 
60.5 
151.7 
17.3 
7.0 
24.3 
6 
51.1 
15.1 
16.2 
82.4 
55.9 
138.3 
21.6 
5.8 
27.4 
Average. . 
~ 55.2 
15.5 
16.1 
86.8 
58.2 
145.0 
19.4 
6.4 
25.8 
• 7 
Uninpculated sul- 
hhur 1000..— 
58.6 
17.8 
11.6 
88.0 
51.2 
139.2 
18.0 
7.8 
25,8 
8 
- do.. 
56.0 
13.6 
18.6 
88.2 
55.9 
144.1 
24.2 
8.4 
32.6- 
’ 
Average.— 
57.3 
15.7 
15.1 
88.1 
53.5 
141.6 
21.1 
8.1 
. 29.2 
9 
inoculated sulphur 
1015.—. 
77.6 
14.9 
35.5 
128.0 
- 69.8 
197.8 
15.7 
10 
59.7 
19.7 
28.5 
107.9 
69.8 
177.7 
17.5 
6.7 
24.2 
Average.. 
68.6 
17.3 
32.0 
117.9 
69.8 
187.7 
16.6 
6.7 
23.3 
11 
Gypsum 1000 -. 
52.2 
15.3 
12.7 
80.2 
55.9 
136.1 
16.8 
5.0 
21.8 
12 
.do__. . 
57.1 
16.1 
13.3 
86.5 
55.9 
142.4 
24.3 
6.7 
31.0 
Average__ 
54.6 
15.7 
13.0 
83.3 
55.9 
139.2 
20.5 
5.8 
26.4 
s McHargue, J. S., and Peter, A. M. the removal of mineral plant-food by natural, 
drainage waters. Ky. jAgr. Exp. Sta. Bui. 237, p. 331-362, illus. 1921. 
