不同植被恢复模式对露天煤矿排土场土壤抗冲性的影响

Effects of Different Vegetation Restoration Models on Soil Scour Resistance in Dump of Open-Pit Coal Mine

为了探究不同植被复垦模式对排土场土壤抗冲性的影响,以辽宁省阜新市海州露天煤矿排土场复垦区内灌木林地(紫穗槐)、榆树林地、刺槐林地、混交林地(刺槐和榆树混交)、荒草地和耕地6种复垦模式为研究对象,采用野外采样和室内改进土壤抗冲槽的方法获取了径流含沙量、抗冲性指数、根系指标和根系对土壤抗冲性的强化值(ΔANS)等评价指标。结果表明:土壤冲刷过程中,不同复垦模式下的径流含沙量在冲刷6 min内变化幅度较大,伴随着冲刷时间的延长,6 min后含沙量相对稳固;不同复垦模式土壤冲刷过程累积径流含沙量表现为耕地较大,荒草地、6986树林地、混交林地和刺槐林地次之,灌木林地较小。土壤抗冲性变化与土壤冲刷过程含沙量呈反比,随土壤冲刷时间延长,土壤抗冲性增强。平均抗冲性指数趋势表现为灌木林地较大,刺槐林地、混交林地、榆树林地次之,荒草地和耕地较小。土壤抗冲性与土壤理化性质的相关性研究表明,在冲刷过程中,土壤容重越小,孔隙度越大,黏粒含量越高,土壤紧实程度越高,土壤抗冲性越强。不同复垦模式土壤抗冲性能强化值(ΔANS)范围为0.06~0.73,强化百分率在28%~630%;植物根系对土壤抗冲性变化特征表现为:灌木林地>混交林地>刺槐林地>榆树林地>荒草地>耕地,植物根系对灌木林地的强化作用最为明显。

In order to explore the effect of different vegetation reclamation models on soil scour resistance of dump,the shrub land(Amorpha acacia),elm forest land,Robinia pseudoacacia forest land,mixed forest land(Robinia pseudoacacia and elm tree mixed),wasteland and cultivated land in Haizhou open-pit coal mine dump of Fuxin City,Liaoning Province,were selected as the study sites.The methods of field sampling and laboratory improvement were used to obtain the evaluation indexes of runoff and sediment content,scour resistance index,root system index and root system strengthening value(ΔANS)to soil erosion resistance.The results showed that the runoff and the sediment content in different reclamation models changed greatly within 6 minutes of scouring,and the sediment contents after 6 minutes was relatively stable with the prolongation of scouring time;the accumulated runoff and sediment content during the soil erosion process in different reclamation models decreased in the order:cultivated land>barren grassland>elm forest land,mixed forest land and Robinia pseudoacacia forest land>shrub forest land;the soil erosion resistance was inversely proportional to the sediment content during soil erosion process,and the soil erosion resistance increased with the prolongation of soil erosion time;the average impact resistance index decreased in the order:shrub land>Robinia pseudoacacia forest land,the mixed forest land,the elm forest land>wasteland and the farmland.The correlation between soil erosion resistance and soil physical and chemical properties shows that the smaller the bulk density is,the greater the porosity is,the higher the clay content is,and the higher the soil compactness is,the stronger the soil scour resistance is.The strengthening values of soil scour resistance(ΔANS)of different reclamation models were in the range of 0.06~0.73,and the percentage of reinforcement was between 28%and 630%;the plant root resistance to soil decreased in the sequence:shrub land>mixed forest land>Robinia pseudoacacia forest land>elm forest land>barren grassland>cultivated land.