Soil respiration and carbon sequestration response to short-term fertilization in wheat-maize cropping system in the North China Plain

Fertilization significantly influences the soil physicochemical properties and crop growth in agricultural ecosystems, yet our understanding of its impact on soil respiration remains limited. To bridge this knowledge gap, we conducted a comprehensive study in the winter wheat-summer maize rotation system of the North China Plain. We examined the driving factors and processes governing soil respiration, and its temperature sensitivity (Q10), in response to various fertilization treatments, including an unfertilized control (CK), organic fertilizer (OM), organic fertilizer in combination with mineral fertilizer (OMNPK), and mineral fertilizer (NPK). Our findings revealed significant changes in Q10 values under different treatments. In maize, Q10 values increased by 4.4 % in OM, 19.9 % in OMNPK, and 15.5 % in NPK treatments. Conversely, in wheat, Q10 values decreased by 9.9 %, 9.6 %, and 7.7 % under OM, OMNPK, and NPK treatments, respectively. Fertilization led to a substantial increase in mean soil respiration of both maize (6.6 %-12.7 %) and wheat (10.1 %-21.3 %). Moreover, fertilization significantly enhanced crop yield, stem biomass, and root biomass. In maize, soil respiration exhibited a linear increase with rising soil pH value, ammonium nitrogen and available potassium content, and crop biomass. Similarly, wheat soil respiration showed a linear trend with increasing soil pH value, total phosphorus, and soil organic carbon content. Structural equation modeling highlighted key factors contributing to variations in soil respiration. For maize, available potassium content, soil temperature, soil water content, and crop height explained 89 % of the variation. In wheat, pH value, total phosphorus, and total potassium content, soil temperature, soil water content, crop height, and crop biomass collectively accounted for 93 % of the variation of soil respiration. Fertilizer application significantly enhanced crop yield and carbon emission efficiency, specifically in wheat. Fertilized plots exhibited carbon emission efficiency 0.78-2.06 times higher than unfertilized plots in wheat. Among all treatments, OMNPK treatment maintained high yield, carbon emission efficiency, and net carbon sequestration in wheat. In summary, during winter wheat cultivation in the North China Plain, the practice of organic fertilizer combined with mineral fertilizer emerges as a superior strategy. This approach not only sustains crop yields but also augments carbon sequestration in crops, demonstrating its significant potential for agricultural carbon management.