Grain yield (0% moisture) per unit of N in grain (GPN), N in grain per unit of available N (NGE), and nitrogen use efficiency expressed as grain yield (0% moisture) per unit of available N (NUEG) in maize as affected by row spacing and N rate during two growing seasons at physiological maturity.

Table 4: Grain yield (0% moisture) per unit of N in grain (GPN), N in grain per unit of available N (NGE), and nitrogen use efficiency expressed as grain yield (0% moisture) per unit of available N (NUEG) in maize as affected by row spacing and N rate during two growing seasons at physiological maturity.

Treatment			Season 1			Season 2
			GPN	NGE	NUEG	GPN	NGE	NUEG
			----------------------------------------kg kg^-1------------------------------------------
Irrigation	70	180	95.5	0.3	28.9	97.4	0.34	33.2
		0	101.7	0.42	42.7	116.1	0.40	46.3
	35	180	97.8	0.29	29.3	92.0	0.35	32.4
		0	89.5	0.59	50.9	124.7	0.47	58.7
Rain fed	70	180	91.1	0.34	30.4	77.8	0.41	31.8
		0	87.3	0.51	43.7	117.1	0.48	55.7
	35	180	109.3	0.34	36.2	77.9	0.45	35.8
		0	104.3	0.61	62.4	126.1	0.53	66.7
Av. Irrigation	Irrigation Rain fed		96.3	0.4	37.9	107.1	0.39	42.6
Av. Irrigation	Irrigation Rain fed		98	0.45	43.2	100.9	0.46	47.3
Av. N rate (kg ha^-1)		180	95,1	0.32	31.1	86.3	0.39	33.1
Av. N rate (kg ha^-1)		0	99.2	0.53	49.9	121.7	0.47	56.8
Av. Row spacing (cm)		70	93.9	0.4	36.4	101.6	0.40	41.5
Av. Row spacing (cm)		35	100.4	0.46	44.7	106.4	0.45	48.4
Analysis of variance
Irrigation (I)			ns	ns	ns	ns	^*	ns
Nitrogen (N)			ns	^**	^**	^**	^**	^**
Row spacing (R)			ns	§	^**	ns	^*	^*
I^*N			ns	ns	ns	ns	ns	^*
I^*R			ns	ns	^*	ns	ns	ns
N^*R			ns	^*	^*	ns	ns	^**
I^N^R			ns	ns	ns	ns	ns	ns
CV (%)			12	13.8	12.4	12.7	7.2	7.6

§; *; **. Significant at the 10. 5 y 1% de probability levels respectively.