Reduction of yield risk of winter wheat by appropriate irrigation based on APSIM model

The North China Plain (NCP) is the main winter wheat production area in China. However, grain yield of winter wheat is often threatened by drought, leading to a high risk of yield. Assessment on yield risk and study on how to reduce yield risk by appropriate irrigations could provide suitable instructions for irrigation management and increasing yield. By using the simulation model APSIM, taking Beijing and Yucheng as case study areas, yield risk of winter wheat in those two areas were evaluated firstly. Then irrigation schemes were designed and their contributions to reduce yield risk in different rainfall years were analyzed. Results indicated that in most years, rainfall could not meet the requirement of wheat, and in 30% of years water shortage reached serious degree. In serious drought years, yields of winter wheat were only 2 445 and 2 466 kg/hm2 in Beijing and Yucheng, respectively. After irrigation, yield risk was reduced greatly, while the appropriate irrigation schemes were varied in different rainfall year types. Synthetically considering reducing yield risk and increasing water use efficiency, three irrigations are appropriate to be given in serious and medium drought years at the stage of before sowing, jointing and flowering. For light drought years, two irrigations at the stage of before sowing and jointing, respectively, are sufficient to reduce yield risk as low as possible.