Coupling Effects of Soil Carbon and Nitrogen Mineralization on Crop Growth in Response to Tillage Practices

ABSTRACT Soil carbon (C) and nitrogen (N) mineralization are critical processes influencing C sequestration and soil fertility. However, the effects of tillage practices and the rhizosphere on these dynamics remain poorly understood. This study evaluated the impacts of long‐term tillage practices (no‐till, conventional tillage, and rotary tillage) and straw management (with or without straw return) on soil C and N mineralization, active C and N pools, and crop growth in a wheat‐maize cropping system. The results demonstrated that straw return significantly enhanced average soil C and N mineralization by 279.7 mg C kg −1 and 11.3 mg N kg −1 soil, respectively ( p < 0.05). The average cumulative mineralization of C and N in rhizosphere soil was 1.9%–19% and 2.3%–17% higher than that in bulk soil, respectively. Rhizosphere interactions and microbial biomass dynamics affect crop N availability by modulating the linkage of active C and N pools to mineralization rates. Notably, soil C and N mineralization exhibited stronger coupling effects on wheat ( Triticum aestivum ) ( r = 0.77, p < 0.001) than on maize ( Zea mays ) growth, likely due to differences in nutrient demand, root architecture, and rhizodeposition. This study highlights the vital function of soil C and N mineralization in regulating nutrient availability and crop growth. Sustainable tillage management provides synergistic strategies that balance C sequestration and N availability, thereby reducing environmental impact and improving agricultural sustainability.