我国四种典型土类有机碳剖面分布特征

Profile distribution of organic carbon of four typical soils in China

以中国黑土、褐土、水稻土和砖红壤4种典型农田土类为研究对象,分析了不同土类有机碳、碳氮比和有机碳密度的剖面分布特征。结果表明:土壤有机碳含量随土层加深而呈现递减趋势;褐土有机碳含量最低,固碳潜力较大;黑土、砖红壤C/N比值明显高于水稻土和褐土,各类土壤耕地表层土壤C/N比值与第二次土壤普查数据相比有明显降低,有可能会影响土壤氮循环与农田环境;不同土地利用类型对土壤有机碳含量和有机碳密度均有显著影响。

The organic carbon contents, C/N ratios and organic carbon density of four typical cropland soil types （black soil, cinnamon soil, paddy soil and latosol） were studied. The result indicated that the SOC （organic carbon content） decreases with soil depth. While the SOC of cinnamon soil is the lowest, the carbon sequestration potential is large. The C/N ratios of black soil and latosol were higher than cinnamon and paddy soil. All the C/N values of the topsoil of farmlands are lower than those of the second national soil survey in China. As a consequence, it may influence the nitrogen cycling and the ecological environment. There is obvi ous difference in organic carbon content and organic carbon density among these soils under different land use.