Straw returning enhances oxygen radical scavenging capacity by modulating of AsA-GSH pathway in maize subjected to water deficit.

INTRODUCTION: Global warming is altering crop growing conditions across diverse climate zones worldwide. In particular, drought stress, a major abiotic constraint, severely restricts the potential for maize yield improvement. The implementation of effective soil improvement and water-saving agronomic practices has emerged as a key measure for mitigating climate change and promoting sustainable agricultural development. This study aims to systematically investigate the effects of straw returning on maize grain yield under water-limited conditions by improving soil properties and modulating the ascorbate-glutathione (AsA-GSH) cycle. METHODS: This study was conducted over a two-year field period using six maize varieties-DK159, MC703, A2636, 303×178, ZQ1, and ZJ330-as experimental materials. The experiment employed tillage methods as the primary treatment, with two levels: straw returning (ST) and traditional plowing (TP, without straw return). Based on this, two water management regimes were implemented: drought stress (DS) and normal irrigation (NI). This study analyzes the differential responses of various maize varieties under the interaction of different tillage practices and moisture conditions. RESULTS: Straw returning can effectively improve soil conditions under drought stress, by regulating the levels of antioxidants and the activities of antioxidant enzymes in the AsA-GSH cycle, it promotes the efficient scavenging of reactive oxygen species (ROS), reduces oxidative damage to crops caused by environmental stress, and thereby helps maintain relatively stable yields. This study indicates that, compared with traditional plowing, straw returning increased maize yields by 0.42%-29.64% under drought stress. Among the various treatment combinations, straw returning (ST) + normal irrigation (NI) Treatment Combination produced the best soil quality and the highest yield. IMPLICATIONS: The findings of this study provide theoretical support for improving farmland soil quality, enhancing maize drought tolerance, and maintaining grain yield, while also laying a foundation for further research on crop responses to drought stress.