Research On Hydrodynamic Properties Of Soil Water In The Unsaturated Zone Of Coal Mining Area During The Process Of Ecological Restoration

The foundation of ecological restoration is vegetation,premise is water,and the key is soil water.Soil water is significant to vegetation growth and succession.The pollutant infiltrated with soil water that is main carrier to pollutant transport and the progress of pollutant migration is very complicated due to its properties and effects of surrounding environment.In this study,soil physicochemical properties,soil water characteristic curve,unsaturated hydraulic conductivity were conducted in sample sites that settled in different ecological restoration areas,in order to reveal soil water infiltration process and analysis the relationship between soil conductivity,water-holding capacity,water-supplying capacity,readily available water content and soil physicochemical properties during the ecological restoration progress.The kinetics adsorption experiments,isothermal adsorption experiments and soil column experiment were carried out to analysis adsorption characteristics of soil for Cr(?)and predicted its migration in soil.Results showed:The exponential function fitting between suction and unsaturated hydraulic conductivity was good(r~2>0.9).Under the same suction,the big soil bulk density had smaller unsaturated hydraulic conductivity.There was a negative correlation between soil unsaturated hydraulic conductivity and soil bulk density,and a positive correlation between soil porosity and unsaturated hydraulic conductivity.The soil adsorption characteristics for Cr(?)was described well by liner and Freundlich adsorption equation.When the concentration of Cr(?)was0.005mg/L,the concentration of Cr(?)at monitoring point of 0.5m,1 m,1.5m and 2m would approached 0.005mg/L at 0.76,1.52,2.28 and 3.04 years respectively.The soil bulk density and compactness decreased but structural stability,organic,total nitrogen content increased with years since ecological restoration,while water-holding capacity,water-supply capacity and readily available water content increased and approached to the undamaged area gradually.But soil bulk density,compactness,structure stability and other nutrient element were still low in 20-40cm soil depth.