中文摘要：

对霍山县第二次土壤普查历史记载资料和2005-2008年耕地监测资料数据进行了统计分析。结果表明,20年来该县农田表土有机碳含量明显提高,显示农田土壤的有机碳库积累。县域范围内耕地土壤有机碳含量不同尺度的变异系数介于4.53%~14.91%。村民组单元内变异性最高,乡镇间有机碳含量变异性低于行政村间变异性。因此,从县级尺度的农田土壤碳计量来说,以乡镇尺度采样研究比村级尺度可靠性较高。影响县域内农田土壤有机碳含量与变异的动力因子主要是农业利用和农田基本建设,茶、桑和水稻利用下农田土壤有机碳含量明显较高。

英文摘要：

Spatial changes in soil organic carbon contents of croplands and the controlling factors have been the fundamental issues for estimating SOC stock and C sequestration potential.In this paper,archived data were obtained from the 2nd national soil survey and the recent soil monitoring over 2005-2008 of the Huoshan County,Anhui Province.A SOC distribution data set was established.Statistical analysis was conducted for the soil monitoring database focusing on the SOC changes within different spatial scale in the county.The results showed that the SOC content of the county＇s croplands had been increased over the last 20 years,evidencing a SOC accumulation in the croplands.The variation coefficient of SOC of the analyzed statistical units ranged from 4.53% to 14.91%,depending on the size of the spatial scale.Intra-Hamlets＇ variation was shown much stronger compared to intra-village and intra-townships variations.However,inter-township variation was smaller than inter-villages.Thus,sampling and statistics of SOC contents at spatial scale of townships might offer higher reliability for county level SOC stock and change the estimation results.Prominent factors that controlling SOC concentrations included land use types,agricultural managements with high SOC storage under tea,mulberry and rice cultivation in the tested counties.