Table 1.

Treatment effects (p values) for dry matter accumulation (DMA), and grain yield (GY) at silking (SS) and physiological maturity (PMS), using year, mulch, nitrogen fertilizer application rates, and planting density as four fixed factors

Sources	DMA-SS	DMA-PMS	GY
Year (Y)	<  0.001	0.001	<  0.001
Mulch (M)	<  0.001	<  0.001	<  0.001
Nitrogen (N)	<  0.001	<  0.001	<  0.001
Density (D)	<  0.001	<  0.001	<  0.001
Y * M	ns	ns	ns
Y * N	ns	ns	<  0.001
Y * D	ns	ns	0.006
M * N	<  0.001	<  0.001	<  0.001
M * D	ns	0.017	<  0.001
N * D	0.001	ns	<  0.001
Y * M * N	ns	ns	ns
Y * M * D	ns	ns	ns
Y * N * D	ns	ns	ns
M * N * D	0.005	ns	<  0.001
Y * M * N * D	ns	ns	ns

Note: ns Not significant (p > 0.05)