Amelioration effects of mineral-organic compound conditioner on Pb-contaminated soil

CAI Ru-meng;SHI Lin;College of Environment and Energy,South China University of Technology;The Key Lab of Pollution Control and Ecosystem Restoration in Industry Cluster,Ministry of Education,South China University of Technology;

potassium calcium silicon fertilizer;;brown coal huminite;;soil amelioration;;Pb;;pakchoi

In this study, a pot experiment was conducted to investigate the effects of a mineral-organic compound conditioner(potassium calcium silicon fertilizer + brown coal huminite)on soil p H, organic matter content, available Pb concentration, growth of pakchoi, and Pb uptake by pakchoi. Compared to the control, application of the compound conditioner decreased the concentrations of available Pb in soil(by67.47% at 2 g·kg~(-1) of compound conditioner)and elevated the soil p H(from 5.34 to 6.25)and soil organic matter content(by 10.98%~13.41%). The concentrations of mineral nutrients(K, Ca, Mg, Si)in the soil increased to various degrees, and the application rates of the compound conditioner had significant positive correlation with soil available Ca and Mg. Applying the compound conditioner could effectively reduce Pb concentrations in the shoot and root of pakchoi. The biomass and stem length of pakchoi increased by 22.79% ~49.90% and2.91%~7.15%, respectively, and both had significant positive correlations with application rates of the compound conditioner. In conclusion,the compound conditioner could effectively ameliorate soil physicochemical properties, decrease bioavailability of Pb in soil, suppress the harmful effects of Pb on crop growth, and enhance soil nutrient supply capacity. The compound conditioner can be used for in situ remediation of heavy-metal-contaminated soil.