中药渣配合氮磷肥施用对铅锌尾矿的改良效果研究

Effects of Medicinal Herb Residue Combined with Nitrogen and Phosphorus Fertilizers on Plant Growth and Physico-chemical Properties of a Pb/Zn Mine Tailings

采用盆栽实验,在铅锌尾矿中添加中药渣、氮肥、磷肥及其组合,从植物生长、营养元素、土壤酶活性、尾矿及植物重金属含量等方面研究其对铅锌尾矿的改良效果。结果表明:添加中药渣配合氮磷肥不同程度地促进了黑麦草的生长,增加了有机质、铵态氮、有效磷含量,提高了土壤酶活性,降低了尾矿及植物中重金属含量,其中中药渣、中药渣+氮肥、中药渣+磷肥,中药渣+氮肥+磷肥处理组效果较好;典范对应分析表明,中药渣、中药渣+氮肥、中药渣+磷肥、中药渣+氮肥+磷肥处理与有机质、铵态氮、有效磷、脱氢酶、β-葡萄糖苷酶、脲酶和磷酸酶有较强的相关性。综合分析表明,在铅锌尾矿的改良修复中添加中药渣作为改良剂,配合氮磷肥施用有助于缓解尾矿重金属毒性,改善营养状况,促进微生物活性,有利于尾矿废弃地的生态恢复。

Medicinal herb residue(MHR)is a waste material after making traditional Chinese medicine. Here we explored its potential to rehabilitate Pb/Zn mine tailings in a pot experiment. Plant growth and physico-chemical properties of a Pb/Zn mine tailings were evaluated after applying medicinal herb residue in combination with nitrogen and phosphorus fertilizers. Results showed that adding medicinal herb residue in combination with nitrogen and phosphorus fertilizers decreased concentrations of diethylene-triamine-pentaacetic acid(DTPA)-extractable Cd, Cu, Pb and Zn in the mine tailings, but increased content of organic matter, ammonium-N and available P and enhanced enzyme(dehydrogenase, β-glucosidase, urease and phosphatase)activities in the tailings. The metal concentrations in plant tissues were reduced by addition of medicinal herb residue. These effects were greater in all treatments with MHR than that without MHR. Canonical correspondence analysis(CCA) revealed that all the treatments were clustered into three groups based on the variation in physico-chemical properties of the mine tailings. The position of CK on the negative part of the Axis 1 indicated a positively correlation with the extractable metal concentrations. In contrast, the treatments of MHR, MHR+N, MHR+P and MHR+N+P were all positioned in the positive part of the Axis 1, suggesting higher organic matter, ammonium-N, available P and soil enzyme activities. In conclusion, our results showed that the application of medicinal herb residues together with nitrogen and/or phosphorus fertilizers should be a practical method to reduce metal bioavailability, increase soil nutrients, and enhance enzyme activities, thereby facilitating ecological restoration of mine tailings.