Agriculture Reference
In-Depth Information
yield (Figure 4C). Without addition of N fertiliser, P addition had no effect on grain yield for
the unlimed treatments in the same season (Figure 4C). In treatments where lime had been
applied, increasing P fertilizer rate had no significant effect on grain yield (Figure 4D).
Application of 30 kg N ha
-1
reduced grain yield (average 13%) in the unlimed plots at 0 and
7.5 kg P ha
-1
compared to treatments where N was not applied (Figure 4C). In the limed plots
grain yield was higher in plots where N had not been applied but the differences were not
significant (p<0.05).
5.0
5.0
B
A
2002-03 (- Lime)
2002-03 (+ Lime)
4.5
4.5
-N: y = 1.95 - 0.21x + 0.033x
2
- 9.95e
-4
x
3
+N: y = 1.52 - 0.30x + 0.047x
2
- 0.0014x
3
-N: y = 2.00 + 0.10x - 0.015x
2
+ 4.76e
-4
x
3
4.0
4.0
+N: y = 1.41 + 0.055x + 0.0011x
2
- 1.77e
-4
x
3
3.5
3.5
lsd
3.0
3.0
lsd
- N
+ N
- N
+ N
2.5
2.5
2.0
2.0
1.5
1.5
1.0
1.0
0.5
0.5
0.0
7.5
15.0
22.5
0.0
7.5
15.0
22.5
11
11
D
2003-04 (- Lime)
C
2003-04 (+ Lime)
C
10
10
-N: y = 6.28 + 0.18x - 0.03x
2
+ 0.001x
3
+N: y = 3.30 + 0.72x + 0.0041x
2
- 2.92e
-4
x
3
-N: y = 3.14 + 0.76x 0.079x
2
+ 0.0021x
3
+N: y = 3.54 + 0.70x - 0.094x
2
+ 0.0029x
3
9
9
8
8
lsd
- N
+ N
7
7
- N
+ N
lsd
6
6
5
5
4
4
3
3
2
2
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 3. Effect of liming, N and P fertilization on P uptake by soybean stover at harvesting. (Error bars
represent least significant difference of means at 95%confidence).
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