Long-term organic amendment reduces the temperature sensitivity of organic carbon decomposition in an upland soil of subtropical China

Abstract

The temperature sensitivity of soil organic carbon (SOC) decomposition determines the feedback of soil carbon (C) pool to climate warming. In the present study, soil samples were collected from a long-term fertilization experiment (since 1986) in a double-corn cropping system. Laboratory soil incubations were conducted to investigate the effect of long-term fertilization on the temperature sensitivity of SOC. Results showed that compared to the initial level, long-term corn cropping without fertilization (control) led to a decline in SOC, while inorganic N, P, and K fertilizer application (NPK) maintained it. Organic amendment combined with inorganic NPK (NPKM) significantly increased SOC relative to the NPK treatment. Warming and organic amendment significantly promoted CO2 release. The temperature sensitivity (Q10) of soil CO2 emissions was significantly lower in the NPKM than in the NPK, while no significant differences in Q10 values were found between the control and either the NPKM or the NPK. Therefore, organic amendment could promote SOC sequestration, and significantly reduce the temperature sensitivity of SOC decomposition in the present subtropical upland soil.