Post-anthesis water use and biomass accumulation in winter wheat under subsoiling and microsprinkler irrigation

The advancement of agricultural mechanization has led to soil compaction and an increased thickness of the plow layer in the North China Plain. By contrast, subsoiling tillage can disrupt the plow layer, enhance the cultivation environment of the soil, and promote crop growth. Nevertheless, such changes in tillage methods often disrupt conventional irrigation systems, highlighting the need to explore alternative approaches. This study employed microsprinkler irrigation, a prevalent irrigation method in crop production, to evaluate how different irrigation regimes affect crop growth in subsoiled fields. Three irrigation lower limits are established in subsoil plots: 70 %FC (MS-H), 60 %FC (MS-M), and 50 %FC (MS-L). For comparison, the study included a 70 %FC surface irrigation treatment with subsoiling (ST) and a 70 %FC surface irrigation treatment without subsoiling (RT). Results indicated that subsoiling border irrigation (ST) increased topsoil moisture and water uptake in the 0-60-cm soil layer. This enhanced water availability led to greater overall water consumption during grain filling, a delayed post-anthesis biomass accumulation, and an extended grain-filling stage, ultimately contributing to increased grain yield. The MS-L treatment increased the utilization of deep soil water owing to lower topsoil water content. However, this limited biomass accumulation leads to early termination of post-anthesis biomass accumulation, a drop in the rate of grain filling, a reduction in the length of grain filling, and a decrease in grain weight. The MS-M treatment, which mainly absorbs water from the 0-30-cm soil layer, considerably increased deep soil water consumption and the duration of post-anthesis biomass accumulation, resulting in a 4.5-day extension of the grain-filling stage and a notable increase in grain weight. While MS-H maintained adequate topsoil moisture, its deep soil water consumption was lower than that of MS-M, resulting in shorter biomass accumulation and grain-filling duration, though still longer than ST, as well as a grain weight not notably different from that of MS-M. Comprehensive TOPSIS analysis identified MS-M as the optimal irrigation regime. Consequently, establishing a 60 % field capacity irrigation threshold for microsprinkler regimes in subsoiled wheat fields effectively promotes deep soil water absorption, boosts biomass accumulation following anthesis, and enhances grain filling, ultimately improving winter wheat yields.