Agriculture Reference
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Rainfed lowland rice
120
12
160
R
140
100
10
R
F
120
F
Cg
80
8
S
100
R
Cg
60
6
80
S
Cg
Cs
60
S
N
40
4
Cs
40
Cs
20
2
Cl
20
Cl
M
M
Cl
V
M
0
0
0
In
Out
In
Out
In
Out
Flood-prone rice
80
12
250
10
Cg
200
Cg
60
Cg
8
150
R
40
6
R
F
F
Cs
R
100
Cs
4
F
S
Cs
20
50
S
2
S
N
0
0
0
In
Out
In
Out
In
Out
Upland rice
100
10
80
Cg
Cg
80
8
60
Cg
Cs
60
6
Cl
40
Cs
Cs
40
4
R
Cl
P
20
20
2
N
Cl
P
R
R
P
G
0
0
0
In
Out
In
Out
In
Out
Figure 7.3 Typical annual nutrient balances for rainfed rice soils from probable inputs
(left side of each graph) and outputs (right side) (data from Greenland, 1997). Inputs
come from R = rainfall, F = floodwater and irrigation, S = sediments, N = nitrogen
fixation and M = manures and fertilizers. Outputs are due to removals in
Cg = rice grain, Cs = rice straw, Cl = legume crop, S = seepage and percolation and
G
=
gaseous emission
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