草原土壤的碳氮含量及其与温室气体通量的相关性

摘要

In the paper, the content characteristics of soil organic carbonand total nitrogen were studied, and correlativity between the content of soil organic carbon and total nitrogen and the fluxes of greenhouse gases CO2, N2O and CH4 were analyzed. All the samples were taken from temperate steppe of Xilin River Basin in Inner Mongolia of China. The results showed that the content of organic carbon range in soil surface layer (0～20 cm) decreased successively from 2.38% to 1.23% and the content of total nitrogen from 0.218% to 0.136% along the precipitation gradient from 470 mm to 150 mm. The contents of the soil organic carbon and total nitrogen had the decreasing trend due to grazing and cultivation. The fluxes of CO2 were significantly positively correlated with the content of the soil organic carbon, the content of soil total nitrogen, C/N ratio and the fluxes of N2O. The fluxes of N2O were significantly positively correlated with the content of the soil organic carbon, soil C/N ratio soil and the fluxes of CO2. The fluxes of both CO2 and N2O had the successively decreasing trend along the precipitation gradient. The fluxes of CH4 had no significant correlativity with the content of soil or ganic carbon, the content of soil total nitrogen, C/N ratio in soil, the fluxes of CO2 and the fluxes of N2O.%通过采样分析研究内蒙古锡林河流域温带草原土壤有机碳及全N的含量特征，探讨它们的含量与温室气体CO2、N2O、CH4通量的相关性，结果表明：沿470～150mm年降水梯度线，土壤表层(0～20cm)有机碳含量从2.38%递减到1.23%，全N含量从0.218%递减到0.136%，而且放牧和开垦都有使有机碳及全N含量降低的趋势；CO2通量与有机碳含量、全N含量、C/N及N2O通量显著相关，N2O通量与有机碳含量、C/N及CO2通量显著相关，且CO2和N2O的通量都有沿降水梯度递减的趋势；CH4通量与有机碳含量、全N含量、C/N、CO2通量及N2O通量都没有显著相关性。