Response of yield for a deficit irrigated crop rotation system: sensitivity of soil hydraulic parameters

Multiple cropping is an effective measure to increase the intensity of land use. The North China Plain is one of China's most important grain production areas, with 70 % of the arable land under double rotation of winter wheat and summer corn. Soil water flow affects the distribution of irrigation water between the two cropping seasons, as the final soil moisture condition of one season is the initial soil moisture condition of the next season. Therefore, yield response and deficit irrigation scheduling are sensitive to soil hydraulic characteristics. The study analyzes this sensitivity depending on factors such as initial soil moisture condition, soil texture, and irrigation scheduling under different levels of limitation in irrigation water. Simulation results indicate that under most scenarios, the impact of initial soil moisture conditions on yield was much more significant than that of soil hydraulic characteristics. However, the impact can also vary depending on the selected irrigation strategy and water limitations. Therefore, for optimal full and deficit irrigation in a crop rotation system, the intra-annual irrigation water allocation should consider the soil water flow between two cropping seasons. In addition, an optimal irrigation strategy can largely mitigate the adverse effects of unfavorable soil hydraulic characteristics. Furthermore, the optimal irrigation strategy improves crop water productivity and food security at the same time.