Effects of Growth Stage-Based Limited Irrigation Management on Soil CO2 and N2O Emissions, Winter Wheat Yield and Nutritional Quality

Water scarcity and poor irrigation practices limit crop productivity and increase greenhouse gas (GHG) emissions in arid Northwest China. Therefore, we investigated the effects of five growth stage-based deficit irrigation strategies on the yield, quality, and greenhouse gas emissions of winter wheat. Across treatments, CO2 emissions ranged from 3824.93 to 4659.05 kg ha(-1) and N2O emissions from 3.96 to 4.79 kg ha(-1). Compared with CK (irrigation in all growth stages), GHG emissions decreased significantly in T1, T2, T3, and T4 (p < 0.05). Water stress reduced the wheat yield, compared with CK, but the decrease depended on the stage without irrigation. Across treatments, the wheat yield was between 5610 and 6818 kg ha(-1). The grain protein content decreased in the order T4 > T3 > T1 > T2 > CK. On the basis of a catastrophe progression method evaluation, we recommend T1 as the irrigation practice for winter wheat, because it maintained a high grain yield and quality and reduced GHG emissions. Thus, in practice, soil moisture should be sufficient before sowing, and adequate water should be supplied during the heading and filling stages of winter wheat. This study provides a theoretical basis for exploring the irrigation strategies of high-yield, good-quality, and emission reduction of winter wheat.