458 
Journal of Agricultural Research y 0 i. xxx, No. 
If this were true, gypsum would not 
have any chemical action on the soil 
constituents. But it is evident from 
the discussion of the data obtained 
from experiment 2 that gypsum caused 
an increase in the amount of potas¬ 
sium in the leachings. Again, it is 
difficult to interpret the calcium data 
secured from the soils treated with 
gypsum in both experiments, because, 
first, of the wide variation in the cal¬ 
cium determinations in the water 
extracts from the two control soils in 
experiment 1 and, second, because of 
the wide difference between the dupli¬ 
cate gypsum treatments in the amount 
of calcium found in the leachings in 
the water-soluble magnesium in the 
soils at the close of the experiments. 
Inasmuch as the differences between 
duplicate treatments in most cases are 
greater than the difference noted for 
the various sulphur treatments, it 
seems best to discuss only the total 
water-soluble magnesium data for the 
two experiments; Considering first the 
total water-soluble magnesium for ex¬ 
periment 1, it will be noted that none of 
the treatments had any appreciable 
effect on this element. The data from 
Table VI .—Amount of magnesium in drainage water , leachings, and soil extracts 
Pot 
No. 
Treatment (pounds 
per acre) 
Experiment 1 (field pots)—magnesium in pounds 
per 2,000,000 pounds of soil 
Experiment 2 (green¬ 
house pots)—magne¬ 
sium in pounds per 
2,000,000 pounds of soil 
De¬ 
cember 
Janu¬ 
ary 
and 
Febru¬ 
ary 
March 
and 
June 
Total 
for five 
months 
Soil 
ex¬ 
tracts 
Total 
water- 
soluble 
mag¬ 
nesium 
Leach¬ 
ings 
Soil 
ex¬ 
tracts 
Total 
water- 
soluble 
mag¬ 
nesium 
1 
Control___ 
15.0 
10.7 
45.0 
70.7 
205.2 
275.9 
19.2 
Lost. 
2 
13.4 
5.9 
20.6 
39.9 
189.6 
229.5 
23.5 
187.4 
208.7 
Average. 
14.2 
8.3 
32.8 
55.3 
197.4 
252.7 
21.3 
187.4 
208.7 
3 
Uninoculated sulphur 
186__ 
13.7 
13.2 
15.7 
42.6 
161.8 
204.4 
34.9 
104.8 
139.7 
4 
_do. 
13. 3. 
10.1 
23.9 
47.3 
182.6 
229.9 
50.3 
167.1 
217.4 
Average.- 
13.5 
11.6 
19.8 
44.9 
172.2 
217.1 
42.6 
135.9 
178.5 
5 
Inoculated sulphur 189. 
14.0 
5.6 
19.3 
38.9 
168.7 
207.6 
52.5 
174.9 
227.4 
6 
13. 4. 
6.8 
27.2 
47.4 
167.0 
214.4 
31.7 
155.9 
187.6 
Average.. 
13.7 
6.2 
23.2 
43.1 
167.8 
211.0 
42.1 
165.4 
207.5 
7 
Uninoculated sulphur 
1000.. 
14.5 
7.3 
36.6 
58.4 
172.2 
230.6 
128.6 
156.6 
285.2 
8 
.do-- 
14.1 
6.7 
34.2 
55.0 
142.6 
197.6 
122.5 
130.4 
252.9 
Average. 
14.3 
7.0 
35.4 
56.7 
157.4 
214.1 
125.5 
143.5 
269.0 
9 
Inoculated sulphur 
1015... 
19.1 
8.8 
45.7 
73.6 
93.9 
167.5 
136.7 
137.6 
274.3 
10 
.do__ 
14.7 
10.2 
35.4 
60.3 
168.7 
229.0 
132.1 
123.8 
255.9 
Average_ 
16.9 
9.5 
40.5 
66.9 
131.3 
198.2 
134.4 
130.7 
265.1 
11 
Gypsum 1000.. 
31.9 
39.5 
10.9 
82.3 
158.3 
240.6 
26.8 
148.0 
174.8 
12 
32.3 
44.5 
10.7 
87.5 
147.8 
235.3 
47.2 
116.6 
163.8 
Average.. 
32.1 
42.0 
10.8 
84.9 
153.0 
237.9 
37.0 
132.3 
169.3 
experiment 2. The results do indi¬ 
cate, however, that at least the 
greater portion of the calcium in the 
gypsum is leached away in the drainage 
water. 
EFFECT OF SULPHUR AND GYPSUM ON 
MAGNESIUM 
In Table VI appear the data show¬ 
ing the losses of magnesium in the 
drainage water and leachings and 
experiment 2 show that, while the low 
sulphur additions did not increase the 
amount of soluble magnesium, the high 
sulphur treatments did cause an in¬ 
crease in the amount of magnesium 
going into solution. In this case some 
of the soil magnesium was probably 
used to neutralize some of the acid 
which was produced in the oxidation 
of the 1,000 lbs. of elemental sulphur. 
Gypsum apparently had little effect in 
liberating magnesium from its insol¬ 
uble compounds in the soil. 
