外源有机碳和温度对土壤有机碳分解的影响

Effect of External Organic Carbon and Temperature on SOC Decomposition

研究凋落物等外源有机碳输入和温度变化对土壤有机碳分解的影响对我们深入理解森林土壤碳动态具有非常重要的意义。以亚热带天然次生林和杉木人工林土壤为研究对象,向土壤中添加13C标记的杉木凋落物和葡萄糖,研究不同温度下外源有机碳添加对原有土壤有机碳(SOC)分解的影响。结果显示:外源有机碳添加使原有SOC分解速率显著提高,表现出显著的正激发效应。葡萄糖引发的激发效应强度显著高于杉木凋落物,并且杉木人工林土壤的激发效应强度显著高于天然次生林。激发效应强度随着培养温度升高呈下降趋势。此外,由于外源有机碳的加入,SOC分解的温度敏感性显著降低。研究表明:凋落物输入及温度在亚热带森林SOC周转过程中发挥重要作用。

The effects of e xternal organic carbon addition and incubation temperature on soil organic carbon decomposition are the key factors to predict soil carbon dynamics under climate change in the future. We added13C-labeled Chinese fir litter and glucose into soils from natural secondary forest and Chinese fir plantation fields, and incubated under four different temperatures to investigate the effect of external organic carbon addition on native soil organic carbon(SOC) decomposition. Our results showed that the native SOC decomposition was significantly stimulated due to Chinese fir litter and glucose addition. Glucose induced stronger priming effects than Chinese fir litter, and the priming effects in Chinese fir plantation soil were significant higher than in natural secondary forest soil.Moreover, the extent of priming effects consistently decreased with increasing incubation temperature; and external organic carbon addition significantly reduced the temperature sensitivity of the SOC decomposition. Our findings demonstrated that both external organic carbon and temperature play a vital role in SOC turnover in subtropical forest soil.