Effect of Preplant Irrigation, Nitrogen Fertilizer Application Timing, and Phosphorus and Potassium Fertilization on Winter Wheat Grain Yield and Water Use Efficiency

Table 3

Analysis of variance for main effects and interaction effects of factors affecting grain yield (GY) and water use efficiency (WUE) utilized in this study by growing season.

Source	Year
	2003		2004		2008		2011
	GY	WUE	GY	WUE	GY	WUE	GY	WUE
Water	*	**	*	**	*	*	**	ns
N timing	ns	ns	*	*	ns	ns	ns	ns
N timing × water	*	*	ns	ns	*	*	*	ns
Treatment	***	***	***	***	***	***	***	***
Treatment ×  N timing	*	*	ns	*	*	*	*	*
Treatment × water	***	**	ns	ns	*	ns	***	**
Treatment ×  N timing × water	ns	ns	ns	ns	ns	ns	ns	ns

*, **, and *** are significant at the 0.1, 0.01, and 0.001 level, respectively.
ns: not significant at the 0.1 level.