Evaluating optimized irrigation strategies on crop productivity and field water utilization under micro sprinkling irrigation in typical cropping systems of the Huang-Huai-Hai Plain

Inefficient traditional irrigation methods have negative consequences for agricultural production and the depletion of groundwater resources. This two-year field experiment aimed to evaluate optimized irrigation practices for irrigation efficiency (IE) and water utilization in winter wheat -maize (W -M) and winter wheatsoybean (W -S) annual rotation systems. Four micro -sprinkler -based irrigation strategies were implemented during the winter wheat season, specifically when the soil water content (SWC) of the 40 cm soil layer reached 40% of the field capacity (FC) after sowing. Including W4 (irrigated to SWC at 40 cm reached 60% FC), W6 (irrigated to SWC at 60 cm reached 80% FC), FI (farmer's practice, with irrigation amount of 150 mm per irrigation, the same timing as W6), and a rain -fed (RF) as a control. Summer seasons had no irrigation except for emergence. The WHCNS model simulated water consumption. The results indicated that IE decreased with increasing irrigation volumes, and the W -S system demonstrated higher IE than W -M. Both W4 and W6 achieved the desired wetting zones, while FI resulted in water leakage. Surface runoff was not affected by irrigation. Compared to the FI treatment under both cropping systems, W4 significantly reduced field water losses, particularly deep percolation, by 18.3-39.4%. W6 and FI led to elevated winter wheat transpiration rates, impacting crop yield. W4 had comparable yields to W6 and FI, but higher crop water productivity with average increases of 17.9% and 21.3% in W -M, and 24.6% and 31.4% in W -S, respectively. W4 also showed higher harvest indexes in both systems. The W -S system had more stable interannual yields, higher water -holding capacity, and water use efficiency than W -M. Although RF had great water -saving potential, its yield losses were enormous. These optimized precision irrigation strategies significantly reduce water consumption while achieving substantial yield increases, thereby providing vital support for sustainable agricultural development.