甘肃省张掖—永昌地区土壤有机碳密度估算及其空间分布特征

THE SOIL ORGANIC CARBON DENSITY AND ITS DISTRIBUTION CHARACTERISTICS IN ZHANGYE-YONGCHANG AREA,GANSU PROVINCE

对甘肃省张掖—永昌地区土壤有机碳密度及其空间分布特征进行研究,从地表和深层土壤有机碳密度估算来看,测区有机碳密度在全国处于较低水平,其中表层土壤有机碳密度在山丹军马场地区为最高,深层土壤在中山丹军马场和张掖市区最高,且高于表层土壤,这与张掖湿地深部的还原条件下,有机质被较完好保存有关。从土壤类型来看,有机碳密度最高的是黑钙土,次为黑土,沼泽土最低。在各种土地利用类型中,园地土壤有机碳、无机碳、全碳密度均最高,草地最低。从地貌单元看,准平原中有机碳密度最高,中山次之,风积地形最低。可以看出,土壤类型、土地利用类型、地貌等都会对有机碳密度产生影响。

The study of soil organic carbon density and its distribution characteristics in Zhangye-Yongchang area can contribute to the investigation of land utilization, carbon sequestration and regional climate change based on the multi-target geochemical survey. Ac- cording to the analytical results of average soil carbon density at the depth of 0.2 m and 1.8 m in the study area, the average soil or- ganic carbon （SOC） is much lower than the national value. The SOC at 0.2 m in Shandan Army Horse Ranch is the highest while the SOC at 1.8 m in Shandan Army Horse Ranch and Zhangye has the highest value and is higher than the value at 0.2 m, which should be related to the preservation of organic materials in deep soil. The SOC value of chernozem is much higher than that of black soil and boggy soil. The average values of SOC, SIC and SC in gardens are higher than those of grass which has the lowest values. The average value in peneplain is higher than that in middle mountain and wind-blown terrain which has the lowest value. In brief, the soil type, the land utilization type and the landscape/regional geomorphology can influence the soil carbon density and its distribution.