Dual-mulching under no-tillage promotes maize root growth and improves yield by optimizing soil hydrothermal conditions in semi-arid regions

In dryland agricultural ecosystems, particularly in semi-arid regions, achieving sustainable crop production is crucial. Although no-tillage and mulching are common practices for conserving water and increasing yields, the combined effects of dual-mulching (straw and plastic film) under no-tillage on soil hydrothermal properties, root growth, and yield remain unclear. Based on the long-term field experiment established in the Loess Plateau of China in 2004, this study investigated the effects of conventional tillage (CT), no-tillage (NT), no-tillage with plastic film mulching (NTP), no-tillage with straw mulching (NTS), and no-tillage with dual mulching of straw and plastic film (NTSP) on soil water, temperature, root growth, and maize yield during the 2022–2023 growing season. The results revealed that NTSP significantly increased soil temperature at the 0–15 cm depth during the VE stage, while reducing the average soil temperature at the 0–30 cm depth during the V6-R3 stage (P < 0.05). Compared to CT, NTSP significantly increased soil water content (SWC) and soil water storage (SWS) at various growth stages, thereby promoting increased root density during critical growth stages (P < 0.05). Moreover, NTSP significantly improved grain yield and its components, biomass yield, water use efficiency (WUE), and rainfall use efficiency (RUE). The grain yield of NTSP increased by 17 % and 40 % compared to NTP and NTS (P < 0.05). Correlation analysis indicated a significant negative correlation between soil temperature during the VT-R3 stage and root growth, while SWC at different stages showed a positive correlation with root growth (P < 0.05). SWS had a greater impact on yield than soil temperature, with pre-sowing SWS having the greatest effect on yield. Overall, NTSP improves soil hydrothermal conditions, boosts root growth, and increases yields. It enhances water use efficiency, supports sustainable farming in semi-arid regions, and offers a solution for soil water conservation in dryland agriculture.