Effects Of Coal-Mining Subsidence On Soil Erosion And Land Use In Hilly Area Of Loess Plateau

Coal mining will result in a wide range of mined-out areas,causing the surface subsidence and a large number of cracks.Coal mining subsidence not only threatens land resources,but also produces soil erosion,water loss,biodiversity degradation and other ecological and environmental problems.The study of soil erosion and land use change in the ecological fragile area has great importance,The analysis of soil erosion and land use change caused by coal mining subsidence can provide the basis for ecological restoration and reconstruction.Based on the modified general soil loss equation(RUSLE),spatial information technology GIS was used to extract the information of remote sensing,terrain and vegetation.By comparing the soil erosion and land use condition of subsided land and reclaimed land,the impact of coal mining subsidence on soil erosion land use was analysed.The conclusions are as follows:(1)Coal mining will cause serious damage on the ecological environment of the mining area.Results of field investigation indicated that two new kinds of land have emerged in Pingshuo No.3 coal mine:subsided land and reclaimed land.After the subsiding effects,degeneration of vegetation occured and soil physical and chemical properties changed,land fragmentation degree increased and land quality decreased;After land reclamation,subsided land became available for plants.with the suitable land form,land use efficient also got improved.(2)From 2000 to 2013,the modulus of soil erosion in the subsided land in the mining area was generally increased.Compared with no mining area,the soil erosion intensity distribution had significant changed,and the areas of intensity,severe and the violent in subsidence land increased from 46.09% to 85.11%.In the reclaimed land area,the erosion area occupied by moderate and above moderate decreased,While slight and light area increased.Land reclamation effectively prevented soil erosion in mining area.(3)In 2000-2013,the total amount of soil erosion increased by 13049 t,compared with pre-mining erosion,the amount of soil erosion in the subsided land increased by 4389.61 t,yet the amount of soil erosion in the reclaimed land decreased by 3806.13 t.The soil erosion is affected by six factors,among which slope,slope length and soil and water conservation factors have the most influence.(4)Coal mining changed the land use type and structure.Under the severe disturbanceof pit mining,the amount of cultivated lands decreased and the land use type turned into grassland,which strongly affected the land use pattern in mining area.In order to keep the land use dynamic balance and land quality,appropriate and timely reclamation measures after coal mining are needed.After land reclamation and ecological restoration,the subsided land(original land type was woodland)can be restored to the original land use type and be available for forest.