College of Horticulture and Forestry Sciences/Hubei Engineering Technology Research Center for Forestry Information, Huazhong Agricultural University, Wuhan 430070, China.
Research Institute of Forest Ecology Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.
Sci Total Environ. 2017 Dec 1;599-600:1308-1316. doi: 10.1016/j.scitotenv.2017.05.085. Epub 2017 May 15.
Soil organic carbon (SOC) is an important component of the global carbon pool. It is a critical indicator of soil quality. We studied SOC content (SOCC) and SOC density (SOCD) of the Three Gorges Reservoir (TGR) area in China. Soil samples from 306 sites across the study area were assessed for SOCC, SOCD and bulk density. Total SOC stocks in the TGR area were estimated at 5.82×10Pg. We examined relationships between SOCC and SOCD, and the environmental and land-use/land-cover (LULC) variables. The plow layer (0-0.3m) had a significantly higher mean SOCC (20.6gkg) than the subsoil layer (16.5gkg); elevation, LULC, soil type and soil thickness were the most influential factors affecting SOCC in the plow layer. In the subsoil layer, elevation and soil thickness were dominant in determining SOCC and SOCD. To study the spatial variability of SOC, we used statistical modeling and GIS-based techniques to map the distribution of SOCC and SOCD of the study area. Both SOCC and SOCD in the plow layer showed patchy distribution and were positively correlated with elevation and vegetation coverage. Spatial variability of SOCD in the subsoil layer showed a gradual transition between LULC categories. The lower SOCC of farmland appeared to be related to the repeated removal of agricultural produce from the land. Preservation of permanent vegetation cover and changing of the traditional farming practices will help to improve SOC stock and increase soil productivity in the TGR area.
土壤有机碳 (SOC) 是全球碳库的重要组成部分。它是土壤质量的关键指标。我们研究了中国三峡库区 (TGR) 的 SOC 含量 (SOCC) 和 SOC 密度 (SOCD)。对研究区 306 个地点的土壤样本进行了 SOCC、SOCD 和体密度评估。TGR 地区的总 SOC 储量估计为 5.82×10Pg。我们研究了 SOCC 与 SOCD 之间的关系，以及环境和土地利用/土地覆盖 (LULC) 变量。犁耕层 (0-0.3m) 的平均 SOCC (20.6gkg) 明显高于底土层 (16.5gkg)；海拔、土地利用/土地覆盖、土壤类型和土壤厚度是影响犁耕层 SOCC 的最主要因素。在底土层中，海拔和土壤厚度是决定 SOCC 和 SOCD 的主要因素。为了研究 SOC 的空间变异性，我们使用统计建模和基于 GIS 的技术来绘制研究区 SOCC 和 SOCD 的分布。犁耕层中的 SOCC 和 SOCD 均呈斑块状分布，与海拔和植被覆盖率呈正相关。底土层中 SOCD 的空间变异性在土地利用/土地覆盖类别之间呈逐渐过渡。农田较低的 SOCC 似乎与农业生产物从土地上的反复去除有关。保护永久植被覆盖和改变传统耕作方式将有助于提高 TGR 地区的 SOC 储量和提高土壤生产力。
