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.