Study On The Changes Of Soil Quality After Reclamation Of Coal Mining Subsidence Area

Xuzhou is our country’s important coal base, coal mining caused subsidence land, serious impacton the mining area ecological environment, economic development and people’s normal production,life.Xuzhou is with the sources of energy, raw material industry as the pillar of energy city, large-scalethermal power plants produce large amounts of fly ash discharge.Using fly ash to collapse of filling soilreclamation has been used widely, study of fly ash reclaimed farmland soil quality status, which hascertain practical significance and theoretical significance.Questionnaires on farmers’awareness on subsidence reclamation were conducted in Lake Village inWu town,Jiawang,Xuzhou. Moreover,a new fly ash reclaimed farmland was selected to study thechanges of soil quality after five years reclamation. The results are showed as follows:(1) The majority of farmers were familiar with neither the policies on subsided reclamation norreclamation technology. Most farmers knowed little about fly ash reclaimed for farmland, moreoveronly31%farmers ownered the hope of subsidence reclamation for agricultural land. Thus indicated thatthe farmers had low awareness on the subsidence reclamation, and were not interested in agriculturalproduction in reclamation areas. Farmers wre not satisfied with the performance of the reclamation dueto significantly low productivity and output and input ratio,moreover most farmers planted inaccordance with the habits, and were reluctant to increase agricultural input inccording to reclamationareas’situation.Goverment should strengthen the guidance to farmers to enhance reclamation arable landquality and productivity.(2) Reclamation land was not siutable for agricultural production for high soil bulk density and lowporosity at the initial term of reclamtaion due to mechanical rolling process during reclamation, whileafter five years reclamation, soil bulk density and porosity were similar to the level of ordinary farmland.Fly ash filling Soil was alkaline in reclamation areas, the fly ash layer pH value was higher. Soil organicmatter, total nitrogen contents were low and were significantly lower than the ordinary farmland.Contents of soil available phosphorus were low. The top soil was effected by reclamation years. Afterfive-year-reclamation soil available phosphorus contents were close to the level of ordinary farmland.was above the average. With the reclamation of the year increase, the content of soil available potassiumwas close to the level of ordinary farmland.(3) Reclamation lands filling with existed Cd pollution,2.0mg/kg Cd in soils and up to4.0mg/kgin fly ash layers, being far more than the second class standard in the soil environment quality. Cucontents in soils were20mg/kg, significantly lower than the second class standard in the soilenvironment quality, however the Cu contents in the fly ash layers were close to or above the soilenvironmental quality standards, which induced potential Cu contamination in reclamation areas. Cr, Pd,Zn contents in soils and fly ash layers were significantly lower than that of the soil environmentalquality standards, indicating that fly ash filling reclamation wouldn’t induce Cr, Pd, Zn pollution.