Water-saving potential and irrigation strategies for wheat-maize double cropping system in the North China Plain

Agricultural system models can be used to assess water-saving potential and irrigation strategies by integrating factors of soil, climate and crops, so as to provide theoretical and technical support for soil moisture optimal control.. In this study, RZWQM-CERES was used to simulate crop yield, evapotranspiration and irrigation requirement with various soil water levels and irrigation schedules in a wheat-maize double cropping system from 1961 to 1999 at Yucheng and Luancheng Stations. The results showed that the long-term averaged maximum evpotranspiration and irrigation requirement in wheat season were 632 and 496 mm at Luancheng, which were higher than that at Yucheng. The maximum evapotranspiration values in maize season were similar, which were 395 and 384 mm, respectively. For both two sites, high irrigation requirement concentrated in wheat season from March to May. At Luancheng, however, higher irrigation requirement occurred in June and October. Crop yield response to water stress differed greatly, where lower irrigation was required at Yucheng than at Luancheng for similar objected yield levels becaused of different climate and soil conditions between the two sites. The long-term irrigation schemes simulations showed that booting stage was the most sensitive growth stage of wheat to water stress at the two sites, but the pre-season irrigation showed great different effects on crop yield between the two sites. Based on above results, water-saving irrigation strategies with high water use efficiency and environmental benefits were established for the two sites.