| The mining of open-pit coal mines and the process of soil discharge from the drainage site have caused inevitable damage to local land resources,making it more difficult for the ecosystem to recover.The new soil structure is damaged and water is rapidly lost downward,so that plants cannot absorb sufficient water and the low nutrient content of the new soil makes it difficult to maintain normal plant growth,which makes the ecosystem lose its ability to repair and maintain itself.Therefore,based on the local natural conditions,this study aims to improve the two major problems of water and fertility deficiency in local soils through soil reconstruction,soil improvement and vegetation restoration.Firstly,the soil layer was reconstructed by laying a clay layer below the yellow cotton soil layer as an impermeable layer,and adding water retention agents and organic fertilizers to the upper soil layer to further strengthen the water retention capacity of the soil,and evaluating the water retention performance of the soil in the test field by comparing it with the soil moisture of the newly constructed drainage field.Different vegetation reclamation options were evaluated in terms of soil physicochemical properties,enzyme activity,microbial diversity and subsurface biomass,so as to select the most suitable vegetation reclamation option for the local area,and the following conclusions were drawn.1.Soil layer reconstruction can significantly increase the water content of 40～100cm soil and slow down the rate of water decline.0～40cm soil water saturation water content is slightly lower than the control group,but the rate of water decline is significantly slowed down,and the water content will be greater than the control group after the rainfall.2.Different vegetation reclamation and soil improvement have different effects on soil properties.Among them,crop reclamation and forest land reclamation can significantly increase the content of soil organic matter,alkaline nitrogen,available phosphorus and available potassium in each soil layer.In the layer,the available phosphorus content of the forest land reclamation soil was significantly higher than that of the crop reclamation.Grass reclamation can significantly improve 0～10cm soil organic matter,available phosphorus content and 0～20cm available potassium content.Soil improvement + natural reclamation can significantly increase the content of available potassium in 0-20 cm soil.The 10-year natural reclamation had no significant effect on soil properties.3.Except for soil urease activity,there was no significant effect of various vegetation reclamation methods and soil amendments on soil urease activity.Short-term vegetation reclamation and soil improvement did not change soil urease activity,while long-term natural reclamation significantly increased soil urease activity.For 0-10 cm soils,neither soil improvement nor short-term vegetation reclamation increased soil community diversity,except for agricultural land,other reclamation methods and simple soil improvement increased soil community richness.For 10-20 cm soils,all reclamation methods,except for simple soil improvement,did not affect community diversity and community richness.The dominant taxa in all reclamation methods were Actinomycetes and Aspergillus,and vegetation reclamation could increase the abundance of Actinomycetes.The main phyla positively correlated with soil physicochemical properties were Actinobacteria,Phyllobacterium,Myxococcota,Patescibacteria and Verrucomicrobiota,and those negatively correlated were Acidobacteria and Chloroflexi.The phyla positively correlated with soil enzyme activity were Actinomycetes and Chloroflexi,and negatively correlated were Aspergillus,Bacillus,Cyanobacteria and Bacillus.Soil pH was negatively correlated with urease activity at 0-10 cm,and soil effective phosphorus content was positively correlated with alkaline phosphatase and sucrase at 0-20 cm.4.The below-ground biomass of woodland was significantly greater than that of other sample plots in both soil levels,the below-ground biomass of control was significantly lower than that of other sample plots in both soil levels,and the below-ground biomass of grassland,agricultural land and natural sparse grassland did not differ significantly.The belowground biomass of grassland was significantly greater than that of unplanted sample plots in both soil levels.In the 0-10 cm soil layer,the differences between agricultural land,natural sparse grassland and unplanted sample were not significant,and showed highly significant positive correlations with organic matter,effective phosphorus and fast-acting potassium,and positive correlations with alkaline decomposition nitrogen.In the 10-20 cm soil layer,the below-ground biomass of naturally sparse grassland was significantly greater than that of the unplanted sample,and there was no significant difference between the agricultural land and unplanted sample,and there were highly significant positive correlations with organic matter and effective phosphorus,and no significant correlations with pH,conductivity,alkaline dissolved nitrogen,fast-acting potassium and enzyme activity. |
