采煤沉陷对地表土壤蒸发和植被蒸腾的影响

Effects of Coal Mining Subsidence on Soil Evaporation and Vegetation Transpiration

采煤沉陷严重破坏了风沙区原本脆弱的生态环境,导致荒漠化程度加剧.因此矿区的生态修复问题备受关注.学术界普遍认为沉陷会降低土壤含水量,从而减少土壤蒸发和植物蒸腾,致使生态环境进一步恶化.但是由于观测手段受限,沉陷区土壤蒸发和植物蒸腾一直无法有效观测,以致于该假说至今未得到验证.本研究使用最新的“三温模型+热红外成像”方法,在野外对毛乌素沙地采煤沉陷区和非沉陷区地表裸露土壤蒸发及主要生态修复树种沙柳(Salix psammophila)、油蒿(Artemisia ordosica)、沙棘(Hippophae rhamnoides)、柠条(Caragana korshinskii)的蒸腾进行了观测.结果表明:(1)沉陷区土壤含水量明显低于非沉陷区,下降范围为0.43%~2.43%;(2)沉陷区土壤蒸发和植物蒸腾显著低于非沉陷区.与非沉陷区相比,观测期间沉陷区土壤累积蒸发量、沙柳和油蒿灌丛累计蒸腾量分别下降28.8%、18.6%、16.1%;(3)在沉陷区,深根系的柠条比浅根系的沙柳和沙棘蒸腾量更大,更易于生长.因此,沉陷区生态修复应优先考虑深根系的柠条.本研究通过在野外实测出风沙区采煤沉陷区土壤蒸发和植物蒸腾,证明了风沙区采煤沉陷对生态环境具有显著的负面影响.

Coal mining subsidence has seriously damaged the already fragile ecological environment in the wind-sandy area,and the process of desertification has been intensified.In recent years,the problem of ecological restoration in the mining area has attracted much attention.It is generally believed that subsidence will reduce soil water content,thus further reduce soil evaporation and plant transpiration,and further worsen the ecological environment.However,due to the limitation of observation methods,soil evaporation and plant transpiration in the subsidence area have been unable to be observed effectively.This hypothesis has never been proved.For this reason,the"three-temperature model"combined with thermal infrared imaging was used to observe the evaporation of bare soil and the transpiration of Salix psammophila,Artemisia ordosica,Hippophae rhamnoides and Caragana korshinskii in the field.The study showed that the soil water content in the subsidence area is significantly lower than that in the non-subsidence area,and the decreasing range is from 0.43%to 2.43%.Soil evaporation and plant transpiration in subsidence area were significantly lower than those in non-subsidence area.Compared with the non-subsidence area,the cumulative evapotranspiration of soil,Salix psammophila and Artemisia ordosica decreased by 28.8%,18.6%and 16.1%respectively during the observation period.In the subsidence area,Caragana korshinskii with deep roots has more transpiration and grows more easily than Salix psammophila and Hippophae rhamnoides.Therefore,Caragana korshinskii with deep root system should be given priority in the restoration of subsidence area.This is the new method that can measure the soil evaporation and plant transpiration in the coal mining subsidence area in the wind-sand area.These results also prove that coal mining subsidence in wind-sand area has a significant negative impact on the ecological environment.