Variation Characteristics And Influencing Factors Of Soil Organic Carbon Of Reclaimed Soils At An Opencast Coal Mine In Loess Hilly Region

In order to reveal the effects of vegetation restoration on soil organic carbon inloess hilly-gully region, through field investigation and laboratory analysis, themethod of using spatial sequence instead of time series, correlation analyses wereused for data processing. Variation characteristics of soil organic carbon content andorganic carbon density in coal mining, the process of vegetation restoration and theinfluence of reclamation direction, soil properties, terrain factors on soil organiccarbon in loess hilly region were studied in this paper. The research conclusions are asfollows:（1）Mining activities damage soil and vegetation, accelerate the decompositionrate of organic carbon. It not only lead to soil organic carbon loss, but also changesthe regulation of soil organic carbon in the soil profile and there is risk of soil qualitydegradation.（2）Soil carbon sequestration ability was improved after vegetation restoration.The change trend of soil organic carbon density is consistent with the change trend ofsoil organic carbon content during different stages of vegetation restoration. Soilorganic carbon content and density under different vegetation types have distinctcohesion in the section, namely with the increase of soil depth the organic carboncontent showed a decreasing trend. Reclamation direction leads to the difference oforganic carbon in a certain extent, woodland soil carbon effect is better as a whole.（3）Correlation analysis reflect that soil pH, total nitrogen, C/N will affect thereclamation soil organic carbon content in the local scope. Organic carbon and totalnitrogen, C/N are significantly positive related under different reclamation directions.organic carbon and pH have a significant negative correlation under cultivated landand forest land after reclamation, and soil organic carbon and pH have no obviouscorrelation in grassland after reclamation.（4）Terrain factors also have certain influence on the spatial distribution oforganic carbon. Surface soil organic carbon and altitude in the study area has a linearrelation (1400-1500m), organic carbon and slope show unimodal type curve, the curve fitting equation is: y=-0.2881x2+1.7417x+4.7077，R2is0.9861, Soil organiccarbon in general: half negative slope> half positive slope> sunny slope> shady slope.