青藏高原土壤有机碳的空间异质性及其影响因素

Soil carbon content played an important role in the terrestrial ecosystem carbon cycle. With 93 soil sampling points of alpine grassland on Qinghai-Tibet Plateau, traditional statistics and Geo-statistics methods were applied to make a comprehensive analysis on spatial heterogeneity of the soil samples of 0-10cm, 10-20cm, 20-30cm, 30-50cm in the alpine grassland of Qinghai-Tibet Plateau and its influencing factors to imSpatial Heterogeneity of soil organic carbon of alpine grassland on Qinghai-Tibet Plateauprove the estimation accuracy of SOC. The results showed that SOC content was extremely abundant and decreased with the increase of soil depth. The coefficients of variation of SOC in each soil layer had a medium intensity of variation in space. The determination coefficients of semi-variance fitting were, respectively, 0.922,0.831,0.855,0.525 and the nugget effect values were 0.390、0.440、0.336、0.387, indicating a moderate spatial correlation. Kriging interpolation results showed that the spatial distribution patterns of SOC in all layers were similar and increased from northwest to southeast. SOC content in all soil layers was negatively related (p ＜ 0. 05) to altitude, but positively related to total nitrogen (p < 0.05). SOC of 5-8 slope was the highest, lowest at <5 , and the difference between other slopes was not significant. SOC in different aspects was shown as cloudy slope > half cloudy slope > half sunny slope > sunny slope.