风蚀作用下的土壤碳库变化及在中国的初步估算

土壤有机碳库储量巨大且在表层富集 ,而风力侵蚀具有巨大的卷挟起沙、搬移输运和空间再分配能力 ,对土壤有机碳库的演变具有重要影响。在风力侵蚀作用下 ,风蚀发生地、风蚀土壤输运途中以及风蚀土壤沉降地的土壤有机碳库有着不同的变化过程。基于质量平衡原理 ,可以建立土壤有机碳流失及各路径碳输移量估算的模型。依据第二次全国遥感侵蚀调查以及第二次全国土壤普查数据 ,在GIS支持下 ,分析了中国土壤有机碳库以及风力侵蚀的空间格局 ,并计算得到风力侵蚀作用下中国土壤有机碳库储量变化以及各路径碳输移量。研究表明 ,我国因风力侵蚀造成的土壤有机碳流失量约为 5 9 76× 10 6 tC/yr,风蚀所致CO2 排放约为 2 9 88× 10 6 tC/yr;风蚀所致的土壤有机碳流失主要发生在中国西北部的干旱半干旱的农区和牧区

The influence of wind erosion on soil organic carbon pool and an assessment in China

Due to the tremendous soil organic carbon pool and the high carbon content on surface soil, even a trivial disturbance in surface soil can easily induce great changes of the whole soil organic carbon pool. On the other hand, as a universal geological process on earth, wind erosion has strong capacities to entrap, transport and redistribute the surface soil. Naturally, wind erosion then has important influences on the evolution of soil organic carbon pool. In eroded area, surface soil is eroded and the soil organic carbon pool decreases; in transportation process, soil organic carbon is further transformed and carbon dioxide (CO 2) is emitted; in deposition area, the changes of soil organic carbon pool are more complicated and the carbon pool increases at least in a short term. The redistribution of soil organic carbon over landscape and the emission of CO 2 react on the terrestrial ecosystem and finally affect the carbon budget. Such processes can be modeled by a series of equations based on the mass balance principle. Using the Arc/Info GRID data derived from the 2nd Chinese national remote sensing based soil erosion investigation and the 2nd Chinese national soil investigation, the spatial patterns of the top 20cm soil organic carbon content and wind erosion intensity are described in detail firstly. Soil organic loss and corresponding carbon flux are then estimated supported by GIS techniques. The total soil organic carbon loss induced by wind erosion is about 59.76 10 6t C/yr, including creeping materials of 14.34 10 6t C/yr, saltating materials of 44.82 10 6t C/yr and suspending materials of 0.60 10 6t C/yr. The emitted carbon dioxide (CO 2) is about 29.88 10 6t C/yr, ranging from 11.95 10 6t C/yr to 41.83 10 6t C/yr. The affected areas mainly lie in the Northwest China. The uncertainties in our research depend on the estimation of the eroded soil mass, the ratio of different erosion fluxes and the oxidizing ratio of SOC during transportation.