Deficit irrigation combined with straw mulching maintains maize yield and improves soil quality in semi-arid...

Water scarcity severely limits maize production in semi-arid environments, making it essential to develop water saving management strategies that maintain soil quality and crop productivity.

A field experiment was conducted from May to October 2024 in West Ordos, Inner Mongolia, China, using three deficit irrigation levels (W1: 2625, W2: 2400, and W3: 2175 m³ ha⁻¹) and two straw mulching treatments (F1: 9000 kg ha⁻¹ and F2: no mulching) arranged in a randomized block design. Soil nutrients, enzyme activities, soil organic carbon fractions, soil quality index (SQI), maize yield, water use efficiency (WUE), and irrigation water use efficiency (IWUE) were evaluated.

Increasing deficit irrigation intensity reduced soil nutrients, several enzyme activities, labile organic carbon fractions, and maize yield, whereas straw mulching partly alleviated these negative effects and improved integrated soil quality. Straw mulching improved SQI across deficit irrigation levels, and W2F1 maintained a grain yield comparable to W1F1 while achieving the highest WUE and IWUE. Correlation analysis showed that maize yield was positively correlated with key soil quality indicators, including phosphatase, coarse particulate organic carbon, sucrase, and SQI. Structural equation modeling showed good model fit and explained 72.6% of the variation in maize yield, suggesting that yield responses were associated with both the direct effects of deficit irrigation and mulching management and changes in enzyme activity and organic carbon fractions.

W1F1 showed the highest integrated soil quality, whereas W2F1 provided the best balance between yield maintenance, water saving, and soil quality preservation, indicating that moderate deficit irrigation combined with straw mulching is a feasible strategy for sustainable maize production in semi-arid agroecosystems.