木醋液对Cd污染石灰性土壤理化性质及Cd形态转化的影响

Effects of Wood Vinegar on Soil Physical and Chemical Properties and Cd Speciation Transformation of Cd Contaminated Calcareous Soil

为寻找可行的强化Cd污染土壤植物修复的方法,通过室内培养试验,设置7个不同稀释梯度木醋液添加处理,研究木醋液对石灰性重金属污染土壤的理化性质、酶活性和Cd形态的影响。结果表明:随木醋液浓度升高,土壤pH逐渐降低,EC(除原液外)无明显变化。土壤有机质、碱解氮、有效磷和速效钾含量较CK分别增加0.35%~66.64%,9.74%~96.10%,31.71%~56.64%,8.34%~30.87%。稀释10~100倍土壤脲酶、蔗糖酶和过氧化氢酶活性明显增加,而稀释5倍和木醋液原液处理土壤酶活性显著被抑制(P<0.05)。土壤可交换态Cd含量除稀释5倍处理外较CK均显著升高(P<0.05),增加24.69%~72.40%。各处理Cd的碳酸盐结合态、铁锰氧化物态及有机物结合态含量较CK均升高,分别为6.67%~196.70%,16.24%~80.09%,31.51%~70.32%。Cd残渣态含量与CK相比均显著降低,降幅为45.88%~59.93%(P<0.05)。综上所述,添加适宜浓度的木醋液可提高土壤养分含量和酶活性,促进残渣态Cd向其他形态转化。

In order to find a feasible method to strengthen the phytoremediation of Cd contaminated soil,indoor culture experiments were conducted to study the effect of wood vinegar on the physical and chemical properties,enzyme activities,and Cd forms of calcareous heavy metal contaminated soils.Seven different dilution concentration treatments of wood vinegar were set up,and the soil physical and chemical properties,enzyme activities,Cd forms,and other indicators were measured and analyzed after adding wood vinegar and cultivation.The results showed that soil pH decreased gradually,and EC(except undiluted treatment)did not change significantly with increasing the concentration of wood vinegar.Comparing with CK,the content of soil organic matter,alkali hydrolyzable nitrogen,available phosphorus,and available potassium were increased by 0.35%~66.64%,9.74%~96.10%,31.71%~56.64% and 8.34%~30.87%.The soil enzyme activities(urease,invertase,and catalase activities)were increased significantly in 10-100 times dilution treatments,while soil enzyme activities were significantly inhibited in 5 times dilution and undiluted treatments(P<0.05).Except for the 5 times dilution treatment,the exchangeable Cd content in soil of other treatments was significantly higher than that of CK(P<0.05),increased by 24.69%~72.40%.Comparing with CK,the content of Cd in the carbonate-bound state,iron-manganese oxide state,and organic matter-bound state in all treatments were significantly increased by 6.67%~196.70%,16.24%~80.09%,31.51%~70.32%,and the residual Cd content was significantly reduced by 45.88~59.93%(P<0.05).In conclusion,adding appropriate concentration of wood vinegar to soil could increase soil nutrient content and enzyme activity,and promote the transformation of residual Cd in soil to other forms.