Electron Transfer Capacity as a Rapid Index for Soil Organic Carbon Stability

摘要

Stability of soil organic carbon (SOC) contributes to soil C sequestration and may play an important role in controlling the greenhouse effect.Numerous indexes for SOC stability have been established based on chemical and physical fractions,by which SOC is mainly divided into labile and recalcitrant pools.However,those methods are generally labor and time intensive.In this study,we proposed to use electron transfer capacity (ETC) of soil-derived dissolved organic matter (SDOM) as the index to evaluate the SOC stability,based on the fact that SDOM was the major part of labile carbon in soil.Results showed that the ETC parameters of SDOM,including electron donate capacity (EDC) and electron accept capacity (EAC),exhibited high correlation coefficients with the recalcitrance index (RI) and labile index (LI),which were 0.910 and 0.897 (P＜0.001); 0.564 and 0.554 (P＜0.01),respectively.This study indicated that,ETC,a parameter that can be simply and rapidly obtained by electrochemical methods,was a potential alternative to evaluate the stability of SOC.