城市污泥施用对矿区土壤改良效果及植物生长的影响OA

[Objective]This study is to investigate the effects of different application rates of municipal sewage sludge on mining-area soils,to identify the optimal sludge application rate and dominant plant species,and to provide a theoretical basis and scientific support for the improvement of mining-area soils and the resource utilization of municipal sewage sludge.[Method]Mining-area soil was used as the research object,and municipal sewage sludge was applied as a soil amendment.Six treatments were established:mining-area soil without sludge addition(CK);20%sewage sludge+80%mining soil(T1);30%sewage sludge+70%mining soil(T2);40%sewage sludge+60%mining soil(T3);50%sewage sludge+50%mining soil(T4);and 60%sewage sludge+40%mining soil(T5).Three native gramineous plant species—Elymus sibiricus,Agropyron cristatum,and Elymus dahuricus—were selected as planting materials.The effects of municipal sewage sludge application on soil fertility of mining-area soil and plant growth were investigated.A comprehensive analysis was conducted to evaluate the soil remediation effects under different sludge application proportions and their impacts on plant growth,with the aim of identifying the optimal sludge addition ratio and dominant plant species.[Result]The results showed that different sewage sludge application rates significantly increased the contents of soil organic matter,available potassium,available phosphorus,and alkali-hydrolyzable nitrogen in mining-area soil,while reducing soil bulk density and pH.With increasing sludge addition rates,soil enzyme activities,including urease,acid phosphatase,sucrose,and catalase,exhibited a trend of first increasing and then decreasing,with overall peak values observed under the T3-T4 treatments.At low sludge application levels,sewage sludge promoted plant growth,whereas at high sludge application levels,plant growth was inhibited,and seedling burn symptoms occurred.Comprehensive analysis indicated that the best soil improvement effects were achieved under the treatments of 50%sewage sludge addition combined with Elymus sibiricus(LT4),50%sewage sludge addition combined with Agropyron cristatum(BT4),and 50%sewage sludge addition combined with Elymus dahuricus(PT4).The adaptability of the three plant species followed the order:Agropyron cristatum>Elymus dahuricus>Elymus sibiricus.[Conclusion]Therefore,Agropyron cristatum can be selected as the dominant plant species for the improvement of mining-area soil in combination with a 50%municipal sewage sludge application rate.