Agriculture Reference
In-Depth Information
26
26
A
2002-03 (+ Lime)
B
2002-03 (- Lime)
24
24
-N: y = 17.12 - 0.46x + 0.026x
2
+ 7.03e
-4
x
3
+N: y = 13.33 - 0.09 + 0.016x
2
- 3.91e
-4
x
3
-N: y = 13.45 - 0.42x + 0.07x
2
- 0.0022x
3
+N: 12.39 - 0.96x + 0.15x
2
- 0.005x
3
22
22
lsd
20
20
lsd
- N
+ N
18
18
- N
+ N
16
16
14
14
12
12
10
10
0.0
7.5
15.0
22.5
0.0
7.5
15.0
22.5
26
26
D
2003-04 (+ Lime)
2003-04 (- Lime)
C
24
24
-N: y = 14.43 + 0.37x - 0.012x
2
- 1.74e
-4
x
3
+N: y = 12.37 + 0.86x - 0.082x
2
+ 0.0021x
3
-N: y = 12.67 - 0.45x + 0.08x
2
- 0.0027x
3
+N: y = 8.03 + 0.75x - 0.03x
2
+ 1.19e
-4
x
3
22
22
20
20
lsd
lsd
- N
+ N
18
18
- N
+ N
16
16
14
14
12
12
10
10
8
8
6
6
0.0
7.5
15.0
22.5
0.0
7.5
15.0
22.5
P application rate (kg ha
-1
)
P application rate (kg ha
-1
)
Figure 2.
Effect of liming, N and P fertilization on P uptake by soybean grain. (Error bars represent
least significant difference of means at 95%confidence).
The application of 30 kg N ha
-1
generally reduced stover P uptake by an overall average
of 15% compared to no N addition. In the second season liming improved (overall average
32%) stover P uptake in treatments where N fertilizer had not been applied, while there was
no response to liming in treatments where N fertilizer had been applied (Figure 3 C and 3D).
3.6. Effect of Liming, N and P Fertilization on Grain and Stover Yield
Liming, N and P fertilizer rate had no significant effect on grain yield in the first season
(p>0.05). In the second season liming also had no significant effect on grain yield (p > 0.05).
However, increasing P rate from 0 to 7.5 kg P ha
-1
increased grain yield for unlimed
treatments which received N fertilizer but a further increase in P rate did not improve grain
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