煤炭开采对植被-土壤系统扰动的碳效应研究

Carbon Disturbance Effects in the Vegetation-Soil System Caused by Coal Mining

受煤炭开采影响,矿区内植被、土壤等主要碳汇要素受到不同程度的扰动,在此过程中其碳汇能力被削弱。本文以碳循环、碳源/汇等理论为基础,讨论了煤炭开采对矿区植被-土壤系统碳汇变化的计量方法;利用时空自适应反射率模型构建长时期植被NDVI序列;通过沉陷区和非沉陷区对比提取采矿对植被NDVI的影响;利用CASA模型计算植被NPP损失量;结合沉陷区内外不同土地利用类型土壤有机碳测定结果,得到矿区植被和土壤受扰动的碳收支变化。结果表明,2001-2010年,大同矿区忻州窑煤矿因开采导致的植被NPP损失量为4 613.66t;土壤有机碳增加1 641.169t;植被-土壤系统碳汇量减少6 166.401t,研究对更全面地测度煤炭开发对环境扰动的碳效应具有一定的借鉴作用。

Mining activities and resource destruction are very severe in coal mining areas,and as a result,environmental disturbance can be significant. In previous studies,the passive carbon emission value caused by environmental disturbance was seldom considered when calculating the natural environmental damage of mining. This omission has led to inadequate and inaccurate ecological compensation values. Affected by coal mining,main carbon sink factors such as vegetation and soil are disturbed to different degrees,and the carbon sink capacity of these are weakened in the mining process. In this paper,based on the carbon cycle and carbon source / sink theory,measurement methods for carbon sink changes in vegetation-soil systems caused by coal mining are discussed. Long-term vegetation NDVI sequences were constructed using space-time adaptive reflectance modeling. The influence of mining on vegetation NDVI was extracted through the contraction between subsidence area and non-subsidence area. Vegetation NPP loss was calculated by the CASA model. The carbon sink change calculation method of the vegetation-soil system that includes vegetation biomass and NPP,dead branches,fallen leaves and organic carbon in soil was constructed. Changes in the carbon budget of the vegetation-soil system disturbed by coal mining were combined with the organic carbon value of soil in different land use types inside and outside the subsidence region. The results show that from 2001 to 2010,NPP loss of vegetation in the Xinzhouyao coal mine in the Datong mining area was 4 613.656t,organic carbon in soil increased by 1 641.169t,the carbon sink amount of the vegetation-soil system reduced by 6 166.401t. These results indicate a clear effect on more comprehensive measures of environmental carbon caused by coal mining.