Nan Fu-Sen, Li Zong-Xing, Zhang Xiao-Ping, Cui Qiao, Li Yu-Chen, Xiong Xue-Ting, Yang Xue-Jie, Yang An-le
College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730071, China.
Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
Huan Jing Ke Xue. 2023 Feb 8;44(2):912-923. doi: 10.13227/j.hjkx.202203091.
As the largest terrestrial carbon pool, the spatial distribution characteristics and influencing factors of soil organic carbon have important implications for global carbon cycle processes. Soil organic carbon density (SOCD) and influencing factors were predicted in the Yellow River basin using a mixed geographically weighted regression (MGWR) model based on soil organic carbon density data and environmental factors. The results showed that:① the SOCD ranged from 0-14.82 kg·m and 0-32.39 kg·m for the soil depths of 0-20 cm and 0-100 cm, with mean values of 3.48 kg·m and 8.07 kg·m and reserves of 2.76 Pg and 6.48 Pg, respectively. The high SOCD value areas were mainly located in the southern part of the Qinghai-Tibet Plateau and Loess Plateau, and the low value areas were located in the eastern part of the upper Yellow River and the inland flow area. ②Among the ecosystem types, the SOCD of soil depth in 0-20 cm was in the descending order of:forest>water body and wetland>other>grassland>farmland>settlement>desert, with mean values of 4.52, 4.31, 3.84, 3.73, 2.89, 2.78, and 2.22 kg·m, respectively, and the SOCD of the 0-100 cm soil depth was in the descending order of:water bodies and wetlands>forest>other>grassland>farmland>settlement>desert, with mean values of 9.58, 9.58, 8.85, 8.66, 7.07, 6.81, and 5.29 kg·m, respectively. The SOCR in descending order was:grassland>farmland>forest>desert>water bodies and wetlands>settlement>others, with 1.40, 0.60, 0.47, 0.11, 0.07, 0.06, and 0.05 Pg at a soil depth of 0-20 cm and 3.31, 1.49, 0.99, 0.26, 0.17, 0.14, and 0.12 Pg at a soil depth of 0-100 cm, respectively. ③ The main factors affecting the SOCD distribution were intercept, profile curvature, NDVI, and precipitation; in addition, curvature and silt also had important effects on the deep SOCD distribution in the Yellow River basin. Among the ecosystem types, precipitation and NDVI were the main factors affecting the SOCD distribution. The intercept also had important effects on the SOCD distribution in the all ecosystems except forests, whereas curvature and silt only had important effects on deserts and other ecosystems. These results revealed the spatial distribution of SOCD, influencing factors, and SOCR in the Yellow River basin and can provide a scientific basis for carbon balance, soil quality evaluation, and ecological management restoration and consolidation in the region.
作为最大的陆地碳库，土壤有机碳的空间分布特征及影响因素对全球碳循环过程具有重要意义。基于土壤有机碳密度数据和环境因子，利用混合地理加权回归（MGWR）模型对黄河流域土壤有机碳密度（SOCD）及其影响因素进行了预测。结果表明：①0-20 cm土层的SOCD范围为0-14.82 kg·m，0-100 cm土层的SOCD范围为0-32.39 kg·m，平均值分别为3.48 kg·m和8.07 kg·m，储量分别为2.76 Pg和6.48 Pg。SOCD高值区主要位于青藏高原南部和黄土高原，低值区位于黄河上游东部和内流区。②在生态系统类型中，0-20 cm土层深度的SOCD由高到低依次为：森林>水体与湿地>其他>草地>农田>居民点>荒漠，平均值分别为4.52、4.31、3.84、3.73、2.89、2.78和2.22 kg·m；0-100 cm土层深度的SOCD由高到低依次为：水体与湿地>森林>其他>草地>农田>居民点>荒漠，平均值分别为9.58、9.58、8.85、8.66、7.07、6.81和5.29 kg·m。土壤有机碳储量（SOCR）由高到低依次为：草地>农田>森林>荒漠>水体与湿地>居民点>其他，0-20 cm土层深度的SOCR分别为1.40、0.60、0.47、0.11、0.07、0.06和0.05 Pg，0-100 cm土层深度的SOCR分别为3.31、1.49、0.99、0.26、0.17、0.14和0.12 Pg。③影响SOCD分布的主要因素为截距、剖面曲率、归一化植被指数（NDVI）和降水量；此外，曲率和粉粒含量对黄河流域深层SOCD分布也有重要影响。在生态系统类型中，降水量和NDVI是影响SOCD分布的主要因素。截距对除森林外的所有生态系统的SOCD分布也有重要影响，而曲率和粉粒含量仅对荒漠和其他生态系统有重要影响。这些结果揭示了黄河流域SOCD的空间分布、影响因素及SOCR情况，可为该地区的碳平衡、土壤质量评价以及生态管理恢复与巩固提供科学依据。
