喀斯特石漠化过程中小生境及岩性的演替对土壤有机碳的影响

Relationship Among Soil Organic Carbon and Small Environment and Lithology in the Rocky Desertification Process in Different Karst Landforms

为探讨喀斯特石漠化过程中地表小生境及成土母质岩性的演变对土壤有机碳的影响,以不同喀斯特地貌类型的角度出发,分别从贵州普定、兴义、关岭、荔波及印江县选取对应的喀斯特高原(KG)、峰丛洼地(KF)、峡谷(KX)、原始森林(KY)及槽谷(KC)作为研究区域,分析了0—40 cm土壤层(0—10,10—20,20—30,30—40 cm)及土壤与基岩交界面土层的有机碳含量,分别计算土壤有机碳密度及储量,并分析其空间分布特征及演变规律。结果表明:不同石漠化等级下土壤有机碳含量、密度及储量分别为113.18~163.98 g/kg,1.08~7.32 kg/m2及4.07~24.29 kg,并且呈现出随着石漠化程度的增加而逐渐降低的趋势,同时小生境为石槽以及成土母质岩性为石灰岩及泥灰岩的土壤有机碳含量相对较高。不同喀斯特地貌类型之间土壤有机碳存在较大的差异,在同等的条件下KY及KC土壤有机碳储量相对要高于其他地貌类型。土壤有机碳在喀斯特石漠化演变链上迁移,而小生境及成土岩性的更迭对不同喀斯特地貌类型土壤有机碳在重构空间分布格局具有重要的指示意义。同时喀斯特岩溶地区生态环境复杂多变,要获得评估喀斯特地区土壤有机碳更灵敏的方法,仍需开展进一步研究。

In order to investigate the relationship among soil organic carbon and small environment and lithology in different karst landforms that the Karst plateau(KG),Karts peak-cluster depression(KF),Karst canyon(KX),Karst virgin forests(KY)and Karst trough valley(KC)were taken from Puding,Xingyi,Guanling,Libo and Yinjiang in Guizhou province,respectively.The content of soil organic carbon in soil horizons(0-10,10-20,20-30 and 30-40 cm)and organic carbon in the critical surface between bottom soil layer and bedrock were was tested by the method of potassium dichromate,and then counting out the density and storage of Soil organic carbon,the spatial distribution characteristics of soil organic carbon in different karst landforms was analyzed.The results showed that the content,density and storage of soil organic carbon in different rocky desertification class were 113.18~163.98 g/kg,1.08~7.32 kg/m3 and 4.07~24.29 kg,respectively.The soil organic carbon is gradually reduce with the increasing of kasrt rocky desertification degree,and then the soil organic carbon concentration in stone trough is higher than other small environment types,and the content of soil organic carbon in the soil above on Limestone and Marl are more than other Lithology types as well.There is a large discrepancy of soil organic carbon among different karst landforms,in same ecology environment the soil organic carbon storage in KY and KC are more than other landform types.The soil organic carbon move along the evolution chain of Karst rocky desertification process,and the change of Small environment and Lithology in different karst landforms are play an important role in the spatial rebuild of soil organic carbon.The ecology environment of karst mountainous area is complex.If we want to get a more sensitive method to estimate the soil organic carbon in different karst landforms,further studies concerning soil organic carbon among different karst landforms were required.