Study On Monitoring And Evaluation Of The Quality Of Reclaimed Land In Mining Area

According to the requirement of Land Reclamation Regulations forinstitutionalization, standardization and legalization, as well as the need to developand improve the standard mine land reclamation dynamic monitoring proposed byChina Land and Resource Twelfth Five-Year Scientific and Technical DevelopmentPlan. This dissertation took Pingshuo opencast mine in the Loess Plateau as anexample, from the point of view of minesoils, combined with land use classificationcharacteristics in mining area, and monitoring and sampling of field plots were carriedout in the study area. Through the field investigation and indoor analysis, the sitecondition, physical and chemical properties, productivity as the monitoring indicatorsof mining land quality. Finally, the land quality monitoring and evaluation indexsystem was established, and the land quality of farmland, forestland and grassland inundisturbed stage, damaged stage and reclaimed stage was evaluated. The mainresearch results were as follows:1. According to the characteristics of minesoils, it recommended minesoils to theSuborder of Anthric Entisols, which named Mine Anthric Entisols. It attempted todivide and name minesoils by soil parent material, type area of reclamation, pilingand filing layer thickness or local place name as minesoils’ Subgroup, Tu, Series.2. In view of the current land use classification and the meaning of excavatingland that was not perfect, for the purpose of practical needs of use and managementfor land in mining area, as well as the characteristics of land use and coverage inmining area, it proposed land use investigation and classification in mining area, andattempted to use the way of three level classification to complement the meaning ofexcavating land.3.18monitoring sampling plots were selected in the study area, and theinvestigation and sampling analysis were carried out by the profile and mixedmethods. It found that the local soil as the major reclamation substance could notcause pollution to the environment. The effective thickness of soil is more than60cm,and the whole soil profile texture is loam. The terrain of mining land which had beenremodeled was as the same as the undisturbed plain area, which was more suitable forlarge-scale mechanized farming. The productivity of reclaimed land, such as forestland and grassland except for farmland were improved significantly, which means thereclamation direction of forestland and grassland was the best choice.4. The bulk density of minesoils is higher than the nature soil in the same layer.With the extension of reclamation years, it is gradually near the undisturbed soil onthe surface level. The local soil is alkaline, and the pH of reclaimed land is related toreclamation time, dump ways and terrain slope, while the pH of un-reclaimed land isuniform.5. Stratification of soil organic matter content appeared in the soil profile in theundisturbed farmland and forestland is obvious, while the content of organic matter inthe reclaimed land increased gradually with time, among which the surface soil ofreclaimed forestland has more organic matter. In the view of mixed sampling, the content of organic matter in reclaimed forestland and grassland was higher than thatof the undisturbed land, while the reclaimed farmland has a little lower organic matter,which is related to the reclamation time, terrain slope and dump ways.The total nitrogen content decreased with the increase of soil depth, while inreclaimed land it showed irregular change. In the view of mixed soil samples from thesurface soil, reclaimed farmland had the lowest total nitrogen, which has littlecontacted with reclamation time.In addition to the reclaimed grassland in the slope terrain, the content of totalphosphorus of other reclaimed land was higher than undisturbed land in the samelevel. The available phosphorus content of the reclaimed land is generally higher thanthe undisturbed land in the same layer, but it showed irregular in the soil profile. Inthe view of mixed soil samples, total phosphorus and available phosphorus werehigher than undisturbed farmland and forestland. Total phosphorus of reclaimedgrassland was higher than undisturbed grassland, while the available phosphorus wasopposite.In the view of total potassium content and distribution, it has no differencebetween reclaimed and undisturbed land. The distribution of available potassiumcontent in the undisturbed land was the same, while it in decreased with increasingsoil depth in the reclaimed land. According to the mixed soil samples, both the totaland available potassium were higher than that in undisturbed land.The distribution of organic matter, total nitrogen, total phosphorus, availablephosphorus, total potassium and available potassium in the soil profile was even in theun-reclaimed land. In the view of mixed surface soil, organic matter and total nitrogenwere lower, while the phosphorus and potassium content were high enough, whichmeans the organic and nitrogen fertilizer were needed in the future course ofvegetation reconstruction.6. The quality of reclaimed land is related to the reclamation time, reclamationdirection, and terrain. In Pingshuo mining area, the most important factors ofrestricting land reclamation quality are bulk density, pH and organic matter, so it mustfocus on the three indicators in the process of monitoring.