Physiological efficiency (aboveground dry matter per unit of N uptake, PE), recovery efficiency (N uptake per unit of available N, RE), and nitrogen use efficiency (aboveground dry matter per unit of available N, NUEDM) in maize as affected by row spacing and N rate during two growing seasons at physiological maturity.

Table 3: Physiological efficiency (aboveground dry matter per unit of N uptake, PE), recovery efficiency (N uptake per unit of available N, RE), and nitrogen use efficiency (aboveground dry matter per unit of available N, NUEDM) in maize as affected by row spacing and N rate during two growing seasons at physiological maturity.

Treatment			Season 1			Season 2
			PE	RE	NUEDM	PE	RE	NUEDM
			----------------------------------------kg kg^-1------------------------------------------
Irrigation	70	180	142.8	0.48	68.2	127.1	0.50	63.3
		0	146.3	0.68	100.2	177.3	0.60	106.2
	35	180	145.1	0.48	69.3	131.2	0.49	64.2
		0	131.6	0.87	114.1	164.7	0.68	112.2
Rain fed	70	180	129.1	0.52	67.4	109.1	0.58	63.6
		0	138.6	0.71	98.1	151.0	0.83	124.9
	35	180	134.2	0.53	71.3	108.0	0.65	70.2
		0	140.8	0.75	105.9	150.4	0.87	130.7
Av. Irrigation Irrigation Rain fed	Irrigation Rainfed		141.6	0.63	87.9	150.2	0.57	86.4
Av. Irrigation Irrigation Rain fed	Irrigation Rainfed		134.7	0.63	85.6	132.3	0.73	97.3
Av. N rate (kg ha^-1)		180	137,0	0.50	69.0	119.1	0.55	65.0
Av. N rate (kg ha^-1)		0	138.7	0.75	104.5	163.5	0.75	118.4
Av. Row spacing (cm)		70	139,0	0.59	83.4	143.0	0.63	89.5
Av. Row spacing (cm)		35	137	0.66	90.1	139.6	0.67	94.3
Analysis of variance
Irrigation (I)			ns	ns	ns	§	^*	§
Nitrogen (N)			ns	^**	^**	^**	^**	^**
Row spacing (R)			ns	§	^*	ns	§	§
I^*N			ns	§	ns	ns	^*	^**
I^*R			ns	ns	ns	ns	ns	ns
N^*R			ns	^*	§	ns	ns	ns
I^N^R			ns	ns	ns	ns	ns	ns
CV (%)			9.2	8.6	6.3	7.9	6.6	4.2

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