Apr a8, 1923 Effect of Changing Reaction of Soils upon Azotohacter 291 
TabIvS I .—Ejffeci of mixing an alkaline and an acid soil upon presence of Azotohacter, 
Mixtures of soils A and B a 
Sample No. 
Grams 
of soil A. 
Grams of 
soil B. 
Ph. 
AzQtobact 
No CaCOs added to soil. 
er cultures 
CaCOs added to soil. « 
Jan. 30. 
May 22. 
Dec. II. 
Jan. 30. 
May 22. 
Dec. ii. 
I. 
300 
0 
7. 02 
+ 
+ 
+ 
+ 
-f- 
4 - 
2 . 
300 
0 
6.86 
+ 
+ 
-f 
+ 
4 - 
3 . 
270 
30 
6 .43 
+ 
-f 
4 - 
4 . 
270 
30 
6.32 
+ 
+ 
+ 
“h 
+ 
4 - 
5 . 
240 
60 
5-76 
+ 
+ 
-f- 
•f 
4 ” 
6. 
240 
60 
5-82 
+ 
4 - 
4 - 
7 . 
150 
ISO 
4. 60 
+ 
— 
-f- 
+ 
4 - 
8. 
150 
ISO 
4. 61 
-f 
— 
— 
4 - 
4 - 
4 - 
9 . 
60 
240 
4. II 
+ 
— 
— 
+ 
4 - 
+ 
10. 
60 
240 
4. 09 
+ 
— 
— 
+ 
+ 
+ 
II. 
30 
270 
3 - 79 
+ 
— 
+ 
+ 
4 - 
12. 
30 
270 
3. 90 
— 
— 
+ 
4 - 
4 * 
13 . 
IS 
285 
3 - 77 
+ 
— 
— 
+ 
4 - 
4 - 
14. 
15 
285 
3 * 7 S 
+ 
— 
— 
-f- 
4 - 
+ 
15. 
3 
297 
3 - 7 S 
+ 
— 
— 
+ 
4 - 
+ 
16. 
3 
297 
3- 68 
— 
— 
4 - 
4 - 
4 - 
17 . 
I 
299 
3- 66 
+ 
— 
— 
+ 
4 - 
4 - 
18. 
I 
299 
3 * 65 
+ 
— 
— 
+ 
4 - 
4 - 
19. 
0 
300 
3.68 
— 
— 
— 
— 
— 
20. 
0 
300 
3. 62 
a += Presence of Azotohacter 
—=Absence of Azotohacter 
Experiment set up Jan. 30. Moisture content optimum. Acidity determined electrometrically. 
Table II .—Effect of mixing an alkaline and an acid soil upon presence of Azotohacter. 
Mixtures of soils E and ^ a 
Sample No. 
Grams of 
soil E. 
Grams of 
soil B. 
Ph. 
Azotohacter cultures 
May I. 
May 18. 
June 21. 
200 
0 
7 - 73 
4 * 
+ 
4 - 
199 
I 
7.64 
4 - 
+ 
4 - 
19s 
5 
7.67 
+ 
+ 
4 - 
190 
10 
7.67 
4 - 
4 - 
4 - 
17s 
2S 
7 - S6 
4 - 
4 - 
4 - 
6. 
ISO 
SO 
7. 61 
4 - 
4 - 
4 - 
7 . 
I 2 S 
7 S 
7 * S 2 
4 - 
4 - 
+ 
8. 
100 
100 
7-37 
4 - 
4 - 
4 - 
75 
I2S 
7. 06 
4 - 
4 - 
4 ” 
SO 
ISO 
6. 02 
4 - 
4 - 
4 - 
2 S 
17s 
4. 87 
+ 
4 - 
— 
10 
190 
3 * 99 
+ 
7 
— 
S 
IQS 
3 - 94 
4 - 
4 - 
— 
I 
199 
3 - 74 
— 
— 
— 
IS. 
0 
200 
3 - 64 
® ?= Azotohacter indefinite. 
+= Presence of Azotohacter. 
—=Absence of Azotohacter. 
Experiment set up May i, Moisture content optimum. Acidity determined electrometrically. 
30618—23 - 2 
