Nutrient availability mediates organic carbon turnover in paddy soils through regulating microbial metabolism

作者：Han Sun, Lili Wang, Amit Kumar, Muhammad Auwal, Lukas Van Zwieten, Tida Ge, Yingyi Fu, Yakov Kuzyakov · 发表于：Geoderma · 年份：2025 · DOI：10.1016/j.geoderma.2025.117313 · 被引用次数：15 · 研究领域：Soil Carbon and Nitrogen Dynamics

• NPK fertilization increased microbial growth, biomass and CUE. • The microbial biomass turnover rate was lower in NPK compared to the Control. • The NPK fertilization reduce enzyme activity and microbial respiration. Nutrient availability significantly influences soil microbial communities and the soil organic carbon (SOC) cycle. Yet, the precise response of microbial metabolism, particularly carbon use efficiency (CUE), to varying nutrient levels, and the subsequent impact on microbial respiration in paddy soils, remains a key area of investigation. In this study, we utilized six paddy soils collected across a latitudinal gradient from Northeast to Southeast China to examine the effects of nutrient availability on CUE, employing the 18 O water labeling approach. We also assessed associated microbial metabolic parameters, including growth, biomass, turnover rate, and extracellular enzyme activity, under different nitrogen, phosphorus, and potassium (NPK) fertilization regimes. Our results revealed that the highest NPK amendment rate (NPK H ) generally led to the greatest microbial growth and biomass, coupled with the slowest microbial biomass turnover rates, especially in the southeastern paddy soils. This enhanced growth and biomass accumulation likely resulted from increased CUE following the alleviation of C and nutrient limitations through fertilization. Furthermore, we observed that reducing these limitations led to decreased extracellular enzyme activity and a corresp...