Integrated application of subsoiling tillage and micro-ridge-furrow planting enhances maize yield, water productivity and economic benefit in drought-prone regions

Spring maize cultivation in semi-humid, drought-prone regions like Northwest China is severely constrained by water scarcity, which reduces yields and resource use efficiency. While subsoiling tillage (ST) and rain-collecting micro-ridge-furrow sowing (RS) are promising strategies for alleviating water stress and improving resource capture, the synergistic effects of these practices on soil water dynamics and crop water productivity (WPc) remain poorly understood, hindering the development of optimized water management strategies. A two-year field experiment (2022–2023) compared two tillage methods--conventional tillage (CT) and ST--and two sowing patterns--flat sowing (FS) and RS, forming four treatments: CT+FS, CT+RS, ST+FS, and ST+RS. Results demonstrated that ST+RS significantly enhanced soil water storage (0–200 cm), and promoted root development in shallow (0–20 cm) and middle (20–60 cm) soil layers. These improvements resulted in increases in the leaf area index (LAI), chlorophyll content (SPAD value), and dry matter accumulation. Critically, ST+RS increased two-year average grain yield (GY) by 7–24 %, with the number of grains per ear (GPE) rising by 2–6 % and the 100-grain weight (100-GW) by 3–10 %. WPc and nitrogen uptake efficiency (UPEN) were improved by 8–26 % and 13–38 %, respectively. GY, GPE, 100–GW, were strongly correlated with root traits. The integrated application of ST and RS effectively conserved soil water conservation, increased GY, optimized WPc, and raised economic benefit. Therefore, the adoption of ST+RS is recommended to enhance productivity and resilience in spring maize systems within semi-humid, drought-prone regions.