Effects of land use, climate, topography and soil properties on regional soil organic carbon and total nitrogen in the Upstream Watershed of Miyun Reservoir, North China

• Published in: Journal of environmental sciences (China) Vol. 24; no. 3; pp. 387 - 395
• Main Authors: Wang, Shufang, Wang, Xiaoke, Ouyang, Zhiyun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2012; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,Beijing 100085, China
• Subjects: Carbon; Carbon - chemistry; carbon sequestration; China; clay soils; Climate; cropland; Ecosystem; environmental factors; Environmental Monitoring; grasslands; greenhouse gas emissions; Human Activities; Land use; land use change; Mathematical models; multiple regression analysis; Nitrogen - chemistry; nitrogen content; plantations; principal component analysis; Regional; regression analysis; Reservoirs; Rivers; secondary forests; Soil (material); Soil - chemistry; soil organic carbon; soil properties; soil total nitrogen; topography; Water Supply; Watersheds; 上游流域; 中国; 土地使用; 土壤属性; 土壤有机碳; 多元回归分析; 密云水库; 总氮; China; China, People's Rep., Beijing, Miyun Reservoir; China, People's Rep; soil organic carbon; multiple regression analysis; soil total nitrogen; principal component analysis
• DOI: 10.1016/S1001-0742(11)60789-4
• ISSN: 1001-0742

Soil organic carbon (SOC) and total nitrogen (TN) contents as well as their relationships with site characteristics are of profound importance in assessing current regional, continental and global soil C and N stocks and potentials for C sequestration and N conservation to offset anthropogenic emissions of greenhouse gases. This study investigated contents and distribution of SOC and TN under different land uses, and the quantitative relationships between SOC or TN and site characteristics in the Upstream Watershed of Miyun Reservoir, North China. Overall, both SOC and TN contents in natural secondary forests and grasslands were much higher than in plantations and croplands. Land use alone explained 37.2% and 38.4% of variations in SOC and TN contents, respectively. The optimal models for SOC and TN, achieved by multiple regression analysis combined with principal component analysis (PCA) to remove the multicollinearity among site variables, showed that elevation, slope, soil clay and water contents were the most significant factors controlling SOC and TN contents, jointly explaining 70.3% of SOC and 67.1% of TN contents variability. Only does additional 1.9% and 3% increase in the interpretations of SOC and TN contents variability respectively when land use was added to regressions, probably due to environment factors determine land use. Therefore, environmental variables were more important for SOC and TN variability than land use in the study area, and should be taken into consideration in properly evaluating effects of future land use changes on SOC and TN on a regional scale.