Effects of Nitrogen Rates and Time of Application on Yield of Maize: Rainfall Variability Influenced Time of N Application
Table 2
Partial and marginal analysis as affected by N rates and time of application on maize in 2013 and 2014 cropping seasons.
Trt
TC
2013
2014
N
TA
Yd
Ayd
GB
NB
DA
MRR
Yd
Ayd
GB
NB
DA
MRR
Control
2503
6.7
6.0
22880
20377
—
—
7.9
7.1
27070
24568
—
—
46
4829
8.0
7.2
27360
22531
—
92.6
9.4
8.4
32031
27201
—
113
46
5318
8.2
7.4
27876
22558
—
5.53
10.3
9.3
35262
29944
—
561
46
5488
8.2
7.4
27930
22441
D
—
9.8
8.8
33486
27998
D
—
69
5695
9.3
8.4
31895
26200
—
967
9.3
8.4
31895
26200
D
—
46
5760
6.9
6.2
23683
17923
D
—
9.9
8.9
33775
28015
D
—
69
6076
8.4
7.6
28760
22684
D
8.4
7.6
28760
22684
D
—
69
6332
9.7
8.8
33276
26944
—
117
10.7
9.6
36581
30250
—
30.2
92
6448
9.1
8.2
31195
24747
D
—
10.9
9.8
37191
30743
—
423
69
6548
7.6
6.8
25903
19355
D
—
10.0
9.0
34276
27728
D
—
110
6659
7.3
6.6
24898
18239
D
—
9.4
8.4
32060
25401
D
—
92
6904
10.3
9.2
35129
28225
—
224
9.9
8.9
33858
26954
D
—
92
7059
9.1
8.2
31155
24097
D
—
10.2
9.1
34714
27655
D
—
115
7193
9.4
8.5
32150
24957
D
—
10.1
9.2
34647
27454
D
—
92
7375
9.8
8.8
33477
26102
D
—
9.5
8.5
32309
24933
D
—
115
7630
9.5
8.5
32362
24732
D
—
9.9
8.9
33764
26134
D
—
115
7821
10.0
9.0
34079
26258
D
—
9.4
8.5
32099
24278
D
—
115
8143
8.6
7.8
29478
21335
D
—
10.8
9.8
37071
28928
D
—
Trt = treatment combinations, N = nitrogen rate (kg/ha), TA = time of N application, TC = total cost that varied among treatments (ETB ha−1), Yd = yield of maize (t/ha), Ayd = adjusted yield of maize (t/ha), GB = gross benefit (ETB ha−1), NB = net benefit (ETB ha−1), DA = dominance analysis, MRR = marginal rate of return (%), D = dominated, = previously recommended time of N application, and 1 USD = 22.50 ETB.