Agriculture Reference
In-Depth Information
During the soil incubation, CO
2
emission, N mineralization and C
turnover were greatly affected by both time and soil depth (Table 4.11.2).
While plant species had little significant effect on CO
2
emission, N
mineralization was much higher with soybean compared with sorghum
at both time periods and soil depths.
Increasing temperature increased soil CO
2
emission, N mineralization
and C turnover at 30 days for both soil depths (Table 4.11.3). Likewise, at
60 days, increasing temperature increased soil CO
2
emission, N mineraliza-
tion and C turnover at the 0-5 cm depth and the N mineralization at the
Table 4.11.2.
Effect of plant species and soil depth on CO
2
emission, N mineralization and C
turnover
1
.
C mineralized (mg kg
−
1
)
N mineralized (g 100 g
−
1
)
C turnover (g 100 g
−
1
)
Crop
0-5 cm
5-10 cm
0-5 cm
5-10 cm
0-5 cm
5-10 cm
30 days
Sorghum
154
a
92
a
4.6
a
0.8
a
4.0
a
3.9
a
Soybean
174
a
102
a
12.6
b
1.6
b
3.8
a
4.5
a
60 days
Sorghum
394
a
297
a
11.4
a
2.8
a
10.1
a
12.5
a
Soybean
401
a
294
a
23.0
b
4.8
b
8.7
b
12.9
a
1
Values represent means of three replicates. Means within a column followed by the same letter do
not differ significantly (0.10 level).
Table 4.11.3.
Effect of temperature and soil depth on CO
2
emission, N mineralization and C
turnover
1
.
C mineralized (mg kg
−
1
)
N mineralized (g 100 g
−
1
)
C turnover (g 100 g
−
1
)
Temperature
(
°
C)
0-5 cm
5-10 cm
0-5 cm
5-10 cm
0-5 cm
5-10 cm
30 days
20
135
a
91
a
4.8
a
0.2
a
3.1
a
3.9
a
25
159
b
,b
92
a,b
,b
6.3
a,b
,b
1.6
a,b
3.8
b
4.0
b
30
199
c
108
b
14.7
b
1.8
b
4.7
c
4.7
c
60 days
20
304
a
299
a
11.6
a
2.4
a
7.2
a
12.8
a
25
360
b
308
a
14.9
b
3.8
b
8.4
b
13.2
a
30
528
c
280
a
16.7
c
5.1
c
12.6
c
11.9
a
1
Values represent means of three replicates. Means within a column followed by the same letter do
not differ significantly (0.10 level).
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