Apr. 38. 192$ 
Oxidation of Sulphur in Black Alkali Soils 
299 
Table II.— Tran^ormation of a black alkali soil into a white alkali ' 
No 
sulphur 
added. 
50 mgm. 
sulphur per 
100 gm. soil. 
100 mgm. 
sulphur per 
100 gm. soil. 
200 mgm. 
sulphur per 
100 gm. soil. 
500 mgm. 
sulphur per 
100 gm. soil. 
1,000 mgm. 
sulphur per 
100 gm. soil. 
Indi¬ 
vid¬ 
ual 
tum¬ 
blers. 
Aver¬ 
age. 
Indi¬ 
vid¬ 
ual 
tum¬ 
blers. 
Aver¬ 
age. 
Indi¬ 
vid¬ 
ual 
tum¬ 
blers. 
Aver¬ 
age. 
Indi¬ 
vid¬ 
ual 
tum¬ 
blers. 
Aver¬ 
age. 
Indi¬ 
vid¬ 
ual 
tum¬ 
blers. 
Aver¬ 
age. 
Indi¬ 
vid¬ 
ual 
tum¬ 
blers. 
Aver¬ 
age. 
f 7*8 
1 
7* 6 
( 6.4 
( 5 * 5 
2.8 
Ph. 
9-6 
9.6 
\ 8.0 
[ 7*9 
• 7*1 
• 7-4 
< 7*0 
• 6 . 7 
i 5 * 5 
- 5 * 7 
■ 3*0 
• 3*5 
[ 7*9 
1 
7*4 
1 6.6 
1 6.2 
4. 6 
Sulphates (milli¬ 
f 26 
1 
1 77*6 
1 
95*5 
|is8. 0 
[229.3 
636.3 
grams of S in 100 
{ 26 
> 27.2 
1 72.4 
[ 75*8 
■ 95*5 
■ 94*9 
■{172. 8 
•164.4 
-(225.5 
■211,1 
■436.7 
■ 447 * 7 
gm. of soil). 
1 29-5 
) 
1 77*5 
J 
, 93*6 
[162. 4 
I188.6 
270.0 
Percentage of sul¬ 
phur oxidized.,. 
97 * 2 
67. 7 
67. 6 
36.8 
42.05 
Carbonates (milli¬ 
f 47*2 
f 7*9 
grams of CO3 in 
i SI* 2 
• 49*2 
< 5.9 
• 6.6 
0 
0 
0 
0 
0 
100 gm. of soil).. 
1 49. 2 
1 5*9 
Bicarbonates (mil¬ 
[182 
[102 
[70 
) 
( 38 
1 
f 20 
] 
f 0 
] 
ligrams of HCO3 
(178 
' 177*3 
<104 
103* 3 
(72 
>72.0 
[• 34 * 7 
20. 0 
\ ° 
r 3*3 
in 100 gm. of soil) 
U72 
I104 
174 
' 
1 34 
) 
1 24 
J 
t 10 
) 
^ Cultures incubated 167 days at 25* to 27“ C. 
The results brought out in Tables I and II point out definitely that 
not only is elemental sulphur oxidized readily to sulphuric acid, which 
results in the neutralization of the carbonates of the soil, but the reac¬ 
tion of the soil can be brought down to any desired point, depending 
entirely upon the quantity of sulphur added and the length of time 
during which the sulphur is allowed to be in contact with the soil. 
The next experiment deals with the oxidation of sulphur by pure and 
crude cultures of the sulphur-oxidizing bacteria in alkaline soil under 
steiile conditions. The soil was placed in loo-gm. portions in 250 cc. 
Erlenmeyer flasks; 100, 200, and 500 mgm. portions of sulphur were 
added to the soil portions, which were then thoroughly mixed, then the 
optimum amount of water was added and the flasks were sterilized for 
lyi hours at 15 pounds pressure. The flasks were then inoculated by 
means of a sterile pipette, with 2 drops of the vigorously growing cul¬ 
tures and incubated at 25° to 28° C. Alkaline soils in which active sulphur 
oxidation had taken place were used as the crude alkaline compost. 
The results are given in Table III. 
Table III. —Oxidation of sulphur in alkaline soil by different bacteria 
Incu¬ 
bated 
14 days. 
Incubated 30 days. 
Incubated 60 days. 
Quantity of 
sulphur used. 
Type of culture. 
Ph 
Ph 
Carbo¬ 
nates 
in 100 
gm. of 
soil 
(mgm. 
of 
CO3). 
Bicar¬ 
bonates 
in 100 
gm. of 
soil 
(mgm. 
of 
HCO3). 
Ph 
Carbo¬ 
nates 
in 100 
gm. of 
soil 
(mgm. 
of 
CO3). 
Bicar¬ 
bonates 
in 100 
gm. of 
soil 
(mgm. 
of 
HCO3). 
Sul¬ 
phates 
in 100 
gm. of 
soil 
(mgm. 
of 
S). 
None. 
Control. 
9*6 
9.6 
49.0 
159 
9.6 
52*5 
143 
30.1 
100 mgm. 
Crude alkaline compost. 
7*7 
7*5 
0 
50.0 
7 * 7 
0 
43*5 
115*5 
200 mgm. 
7*4 
6.3 
0 
31*0 
5*6 
0 
8.5 
201. 0 
500 mgm. 
7.0 
4.9 
0 
IS’O 
4 * 7 
0 
6*5 
254*8 
100 mgm. 
Thiobacillus tkiooxidans. 
9.2 
8.8 
8.0 
142.0 
8.6 
0 
86.0 
109.4 
200 mgm. 
8.6 
9.0 
14.7 
127. 0 
7*5 
0 
53*0 
145*3 
500 mgm. 
8.6 
9.0 
5*8 
118.0 
7*4 
0 
45*0 
160. 7 
TOO mgm. 
Thiobacilliis B ... 
8.8 
9.0 
29*4 
18. 5 
15*6 
132. 0 
138-0 
136.0 
8.8 
0 
80. 0 
78. 2 
118.4 
123*3 
200 mgm. 
.do. 
8.2 
8.0 
8.0 
0 
55*5 
48. 0 
$00 mgm. 
! 
8.0 
7*8 
7* 6 
0 
