利用双指数模型预测中国不同森林带土壤有机碳矿化的动态变化

本文利用土壤培养实验和双指数模型(把土壤有机碳划分为活性碳和缓效性碳库)的方法,来分析确定长白山和祁连山的土壤有机碳的动态变化。分析和拟合土壤有机碳矿化释放的CO2的速率。结果表明:活性碳库占总有机碳的1.0%–8.5%,平均驻留时间的平均值为24天;缓效性碳库占总有机碳的91%–99%,平均驻留时间的平均值为179年。根据缓效性碳的大小和平均驻留时间可以得知,祁连山森林土壤的有机碳较长白山的难分解。通过分析影响森林土壤有机碳矿化的因素––土壤粘粒含量、海拔和温度,结果显示两种森林土壤有机碳的分解快慢与其温度正相关,并且长白山和祁连山的累积的土壤有机碳和缓效性碳的含量随土壤粘粒含量的增加而呈线性增加,其相关系数分别为0.7033和0.6575,充分表明温度和土壤粘粒含量对土壤有机碳的矿化有较大的影响。

Predicting dynamics of soil organic carbon mineralization with a double exponential model in different forest belts of China

The dynamics of soil organic carbon (SOC) was analyzed by using laboratory incubation and double exponential model that min-eralizable SOC was separated into active carbon pools and slow carbon pools in forest soils derived from Changbai and Qilian Mountain areas. By analyzing and fitting the CO2 evolved rates with SOC mineralization, the results showed that active carbon pools accounted for 1.0% to 8.5% of SOC with an average of mean resistant times (MRTs) for 24 days, and slow carbon pools accounted for 91% to 99% of SOC with an average of MRTs for 179 years. The sizes and MRTs of slow carbon pools showed that SOC in Qilian Mountain sites was more difficult to decompose than that in Changbai Mountain sites. By analyzing the effects of temperature, soil clay content and elevation on SOC mineralization, results indicated that mineralization of SOC was directly related to temperature and that content of accumulated SOC and size of slow carbon pools from Changbai Mountain and Qilian Mountain sites increased linearly with increasing clay content, respectively, which showed temperature and clay content could make greater effect on mineralization of SOC.