Larger Q10 of carbon decomposition in finer soil particles does not bring long-lasting dependence of Q10 on soil texture - 土壤碳循环与地膜覆盖课题组

Soil particle-size fractionation is a reliable approach for the separation of carbon (C) pools with different stabilities. Our previous study found that C decomposition in fine soil particles had greater temperature sensitivity (Q10) than in coarse particles in grassland and forest soils. However, it is not known whether this phenomenon occurs in cropland soil and whether it generally suggests a dependence of Q10 on soil texture. We did a 107-day incubation of isolated soil particles from cropland soil, including paddy and upland, with contrasting fertilizer applications. The incubation was carried out over three short-term cycles of sequentially changing temperatures between 5 and 30ºC at 5ºC intervals. The results indicated that C decomposition was faster in the sand (>50 μm) fraction than in the silt (2–50 μm) and clay (