喀斯特石漠化综合治理区表层土壤有机碳密度特征及区域差异

Organic Carbon Density Features and Regional Variation of the Topsoil in Karst Demonstration Areas of Rocky Desertification Integrated Rehabilitation

以中国南方喀斯特地区具有代表性的贵州为例,选取3个典型喀斯特石漠化综合治理示范区,以划分出的4条核心小流域为监测单元,对各示范区内及示范区之间不同等级石漠化样地表层土壤有机碳密度特征进行比较。结果表明:各示范区之间表层土壤有机碳密度变异性较大,表现为红枫湖示范区(6.12 kg m-2)>鸭池示范区(5.21 kg m-2)>花江示范区(2.80 kg m-2);不同等级石漠化样地之间土壤有机碳密度整体表现为无明显、潜在石漠化样地大于中、强度石漠化样地;岩石裸露率是影响喀斯特地区表层土壤碳密度的重要影响因子之一,特别对于中、强度石漠化区;地貌、气温和不同工程措施也在一定程度上影响到土壤有机碳密度特征。喀斯特石漠化综合治理具备巨大的固碳减排效应,采取有效措施增加有机碳蓄积量是今后石漠化综合治理的关键。

Guizhou Province was taken as an example for its symbolic representation of Karst landform.And three typical integrated rehabilitation demonstration areas of karst rocky desertification were chosen and four core small drainages were regarded as monitoring units.The comparisons of organic carbon density had been carried out in and between karst pilots of various degrees in demonstration areas.The result showed that there was a great gap of organic carbon density in topsoil of different demonstration areas and ordered as Hongfenghu demonstration areas（6.12 kg m-2） Yachi demonstration areas（5.21 kg m-2） Huajiang demonstration areas（2.80 kg m-2）;while the organic carbon density in desertification areas with different degrees showed the trend of no apparent,potential rocky desertification being stronger than moderate and serious rocky desertification;most of the carbon in the topsoil were located in no apparent and potential rocky desertification;the percentage of exposed rocks was one of key factors to impact carbon density of topsoil in karst areas,especially in the areas of moderate and serious degrees;and the features of organic carbon density in soil were also influenced by landform and temperature and different engineering measures to a certain extent.Integrated rehabilitation of rocky desertification had a huge potential of carbon fixation and pollution reduction,so that increasing organic carbon accumulation would be the key in rocky desertification integrated rehabilitation in the future through using efficiency management.