Table 2.

The ANOVA results for the effects of a fertilizer-N x -P factorial on maize yield conducted for two years at Iburu and Zaria.

Source of variation	SPAD (plant−1)	IPAR (%)	LAI (m2 m−2)	Number of Grains (m−2)	TDM (kg ha−1)	GY (kg ha−1)	PNU (kg ha−1)	NRE (kg kg−1)	AE (kg kg−1)	NUTE (kg ha−1)
Iburu
Nitrogen (N)	∗∗	∗∗	∗∗	∗	∗∗	∗∗	∗∗	ns	∗∗	∗
Yr × N	ns	ns	ns	ns	∗	∗	∗	∗	∗	Ns
Phosphorus (P)	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗
Yr × P	ns	∗	∗	∗	ns	Ns	ns	ns	ns	Ns
N × P	ns	∗∗	∗∗	∗	∗	∗∗	ns	ns	∗	Ns
Yr × N × P	ns	ns	ns	ns	ns	Ns	ns	ns	ns	Ns
Zaria
Nitrogen (N)	∗∗	∗	∗	∗∗	∗∗	∗∗	∗∗	∗	ns	∗
Yr × N	ns	ns	ns	∗∗	∗	Ns	ns	ns	ns	Ns
Phosphorus (P)	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗∗	∗
Yr × P	∗∗	∗∗	∗∗	∗∗	ns	Ns	ns	ns	ns	ns
N × P	ns	ns	ns	∗∗	ns	∗∗	∗∗	ns	ns	∗
Yr × N × P	ns	ns	ns	∗	ns	Ns	ns	ns	ns	ns

Yr = year, SPAD = soil plant analysis development, IPAR = intercepted photosynthetically active radiation, LAI = leaf area index, TDM = total dry matter, GY = Grain yield, PNU = total plant nitrogen uptake, AE = agronomic efficiency, NRE = nitrogen recovery efficiency, NUTE = N utilization efficiency.