Table 2.

Treatment effects (p values) on maize plant total nitrogen uptake at the jointing stage (PNU-JS), tasseling stage (PNU-TS), silking stage (PNU-SS) and physiological maturity stage (PNU-PMS), nitrogen translocation (NT), nitrogen translocation efficiency (NTE), grain yield (GY), water use efficiency (WUE), rainfall use efficiency (RUE), nitrogen assimilating amount after SS stage (NAAS), nitrogen harvest index (NHI), nitrogen use efficiency (NUE), nitrogen apparent recovery efficiency (NRE) and partial factor productivity of the fertilizer (PFP), using cropping year (Y), nitrogen fertilizer levels (N) and plastic mulch (M) as three fixed factors.

Source	PNU-JS	PNU-TS	PNU-SS	PNU-PMS	NT	NTE	GY	WUE	RUE	NAAS	NHI	NUE	NRE	PFP
Year (Y)	<0.001	<0.001	<0.001	<0.001	0.048	0.001	ns	ns	<0.001	0.003	ns	0.003	ns	0.018
N fertilizer (N)	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
Mulch (M)	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	ns	<0.001	<0.001	ns	<0.001
Y × N	<0.001	<0.001	<0.001	<0.001	0.008	<0.001	0.009	<0.001	<0.001	<0.001	<0.001	<0.001	0.002	<0.001
Y × M	0.04	0.001	ns	ns	0.034	0.017	ns	0.024	0.036	ns	0.001	ns	ns	ns
N × M	ns	<0.001	ns	ns	ns	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	ns	0.029
Y × N × M	ns	<0.001	ns	ns	ns	<0.001	ns	ns	ns	0.003	0.015	ns	ns	ns

ns: not significant (p > 0.05).