甘南高寒草甸土壤有机碳储量时空分布特征的模拟分析

Simulation analysis of the spatial and temporal distribution of soil organic carbon storage in Gannan alpine meadow

以甘南州高寒草甸为研究对象,利用CENTURY模型,根据甘南州及周边气象站点1971—2020年的月值气象数据和土壤类型数据,将CENTURY模型参数本地化,使其适用于甘南高寒草甸土壤有机碳储量模拟。对模拟结果进行时空统计,得到甘南州土壤有机碳储量(0~20 cm^(-2))的空间分布和时序变动情况。结果表明:甘南州土壤有机碳储量呈由西南向东北递减,由西向东递减的分布特征,且土壤总有机碳储量与慢性土壤有机碳储量的变动趋势较为一致;1971—2020年甘南州平均土壤有机碳储量为8444.40 g·m^(-2),其中各组分库的土壤有机碳储量分别为270.12 g·m^(-2)(活性)、4516.70 g·m^(-2)(慢性)、3478.77 g·m^(-2)(惰性)。土壤有机碳储量高值地区主要是碌曲县和玛曲县,而合作市的有机碳较低。海拔、气温、降水均对土壤有机碳储量有影响,且土壤有机碳储量的变化在空间上与海拔和降水的变动具有一致性,随温度的升高土壤有机碳储量呈下降趋势。

We examined the spatiotemporal distribution of soil organic carbon storage in Gannan alpine meadow. According to the monthly meteorological data and soil type data from 1971 to 2020 in Gannan and its surrounding meteorological stations, we parameterized the CENTURY model to simulate soil organic carbon storage and its dynamics. The simulation results were used to model the spatial and temporal variations of soil organic carbon(0-20 cm). The results showed that soil organic carbon storage decreased from southwest to northeast in the past 50 years. A similar trend was observed from west to east. The variation of total soil organic carbon storage and was in quite consistent with that of slow fraction. In 1971-2020, the average soil organic carbon storage in Gannan was 8444.40 g·m^(-2). The soil organic carbon storage was 270.12, 4516.70, and 3478.77 g·m^(-2)in the active, slow, passive fractions, respectively. Luqu and Maqu counties were the main areas with high soil organic carbon storage, while Hezuo City had low soil organic carbon storage. Altitude, temperature, and precipitation were the main factors affecting soil organic carbon storage. Spatially, soil organic carbon storage was positively correlated with altitude and precipitation, but negatively correlated with temperature.