Effects of tillage and sowing methods on seedling emergence quality and yield of summer maize following wheat stubble in hilly regions^*

To investigate the effects of mechanized tillage and sowing methods on seedling emergence quality, seedling vigor, and yield of summer maize following wheat stubble in hilly regions, three methods—rotary tillage mechanical sowing (RTMS), no-tillage mechanical sowing (NTMS), and strip-tillage mechanical sowing (STMS)—were tested from 2020 to 2022. The results showed that tillage and sowing methods significantly influenced maize seedling emergence quality. Compared with RTMS and NTMS, STMS increased sowing depth uniformity and qualified seed spacing rate by 31.74% and 39.81%, and 6.65% and 10.86% on average over three years, respectively. The seedling emergence rate and above-ground dry weight under STMS were enhanced by 0.73% and 8.14%, and 97.45% and 51.81%, respectively. Maize yield consistently ranked as STMS > RTMS > NTMS across the three years. Compared with RTMS, NTMS increased grains per ear by 3.16% and 1000-kernel weight by 2.67% on average, but reduced effective ear number by 8.89%, resulting in an average yield reduction of 4.24%. In contrast, STMS increased grains per ear by 2.52%, 1000-kernel weight by 1.81%, and effective ear number by 0.81%, achieving a 6.70% average yield increase over RTMS. Path analysis revealed that effective ear number and 1000-kernel weight contributed 56.12% and 42.07% to yield, respectively. Correlation analysis indicated that effective ear number was highly significantly positively correlated with emergence rate and qualified seed spacing rate, 1000-kernel weight was significantly positively correlated with seedling dry weight , grains per ear were positively correlated with seedling uniformity, and maize yield was highly significantly positively correlated with effective ear number, 1000-kernel weight, emergence rate, and qualified seed spacing rate . Strip-tillage mechanical sowing (STMS) significantly improved seedling emergence quality and vigor, optimized yield components, and ultimately enhanced maize yield, demonstrating its suitability as the optimal mechanized tillage and sowing method for hilly wheat stubble maize.