Abstract: A field experiment was conducted in 2007-2010 to study the effects of no-tillage, sub-soiling, and deep-ploughing combined with balanced fertilization, traditional fertilization, and no (or lower amount) fertilization on the soil water storage, crop yield, water use efficiency (WUE), and economic return of winter wheat-spring maize rotation field in Weibei highland. Among the tillage measures, no-tillage in fallow period had the best effect in soil water conservation, followed by sub-soiling, and deep-ploughing. The average water storage in 0-200 cm soil layer in crop growth period under no-tillage and sub-soiling was 6.7% and 1.9% higher than that under deep-ploughing, respectively. Under the balanced, traditional, and no (or lower amount) fertilizations, sub-soiling all showed the highest yield, WUE, and economic return, with the best effect under balanced fertilization. The three-year crop yield under sub-soiling combined with balanced fertilization was 6909, 9689, and 5589 kg·hm^-2, WUE was 18.5, 25.2, and 23.0 kg·hm^-2·mm^-1, and economic return was 5034, 5045, and 7098 yuan·hm^-2, respectively. It was suggested that balanced fertilization combined with sub-soiling had the best effect in soil water conservation and yield- and income increase, being the more appropriate fertilization and tillage mode for the wheat-maize rotation field in Weibei highland.

Key words: organic carbon., paddy soil, Weibei highland, crop rotation, conservation tillage, soil water storage, yield, water use efficiency, amino sugar, long-term fertilization