Effects of cultivation pattern and nitrogen rate on crop yield and water use efficiency in winter wheat-summer maize system

A field experiment started in 2003, located at Yangling, Shaanxi Province, was conducted to study the effects of longterm cultivation patterns and nitrogen rates on the yields and water use efficiency of winter wheat-summer maize rotation system. The results showed that straw mulching and furrow planting cultivation patterns significantly increased the grain yields of summer maize, and had little effect on the yields of winter wheat compared to conventional cultivation pattern. Watercontrolled pattern decreased the yields of summer maize and winter wheat. The total grain yields of summer maize and winter wheat in the past 6years decreased in the following order: furrow planting straw mulching conventional watercontrolled. Furrow planting pattern significantly increased water use efficiency of winter wheat and summer maize. Straw mulching and watercontrolled patterns had significantly increased the water use efficiency of summer maize, but had little effect on that of winter wheat. Total water use efficiency under winter wheat-summer maize rotation system decreased in the following order: furrow planting straw mulching watercontrolled conventional. Nitrogen rates at 120 and 240 kg/ha significantly increased the yields and water use efficiency of winter wheat and summer maize compared to the no nitrogen fertilizer treatment, but the differences between the two nitrogen rates(N120 and 240 kg/ha)was not significant.