Study on the Use of Soil Amendments for the Remediation of Cadmium-contaminated Soil by Sweet Sorghum
This paper aimed to study the effects of different soil amendments on the Cd phytoremediation effect of sweet sorghum.Pot experiments consisting of no amendment(CK),a single application of biochar(BC),hydroxyapatite(HAP),and combined biochar+hydroxyapatite(BC+HAP)were performed by the cadmium-contaminated farmland soil.The results showed that BC,HAP and BC+HAP all enhanced the peroxidase(POD),superoxide dismutase(SOD),and catalase(CAT)activities of sweet sorghum,regulated the absorption of mineral nutrients nitrogen(N),phosphorus(P),and potassium(K),especially P,and increased soil pH.Com-pared with CK,the BC,HAP,and BC+HAP groups showed increased shoot(by 11.33％,35.48％and 18.81％,respectively)and root(by 13.31％,34.47％and 29.88％,respectively)dry weights,and the growth-promoting effect of HAP was significantly better than those of BC.BC,HAP and BC+HAP all increased the cadmium content and absorption of sweet sorghum,significantly improv-ing their cadmium removal ability from the soil.The BC,HAP and BC+HAP groups showed increased shoot(by 75.51％,59.12％and 47.09％,respectively)and root(by 34.93％,56.20％and 23.75％,respectively)unit mass cadmium extraction.BC and BC+HAP significantly increased the cadmium transfer coefficient of sweet sorghum,while HAP had no significant effect on the cadmium transfer coefficient of sweet sorghum.In conclusion,the single or combined application of biochar and hydroxyapatite all could en-hance the efficiency of sweet sorghum to phytoremediation of Cd-contaminated soil.The single application of biochar obtained the best effect,demonstrating greater potential for practical application.
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