不同磷肥对棕壤吸附铜的影响

Effects of different phosphate fertilizers on copper sorption in brown soil

采用等温平衡法研究3种性质不同的磷肥(磷酸二铵,钙镁磷肥和磷矿粉)对棕壤铜吸附量的影响,并应用Freundlich方程Cs=KfCen分析土壤铜的吸附特征。结果表明,与不施磷肥处理(对照)相比,当n(磷):n(铜)=1:1时,钙镁磷肥和磷矿粉增加棕壤对铜的吸附量,分别增加107%和158%;不同用量的磷酸二铵均会降低棕壤对铜的吸附能力;增加非水溶性磷肥(钙镁磷肥和磷矿粉)的施用量,能增加棕壤对铜的吸附量,提高棕壤的吸附能力;高量磷矿粉的作用效果最为明显。由此可知,为降低农产品质量安全风险,铜污染棕壤上不宜施用磷酸二铵,但可选用磷矿粉作为肥源。

The present paper uses the isothermal equilibrium theory to investigate the effects of different phosphate fertilizers（diammonium hydrogen phosphate,calcium magnesium phosphate,and phosphate rock） on copper sorption in brown soil,and Freundlich equation（Cs=KfCen） to characterize the sorption behaviors of copper.The results showed that both calcium magnesium phosphate（CMP） and phosphate rock（PR） enhanced sorption capability（Kf value） of copper in brown soil with increase rated being 107% for CMP and 158% for PR at n（P）：n（Cu）=1：1,when compared with the non-phosphorus treatment control,while as diammonium hydrogen phosphate（DAP） treatment significantly decreased copper sorption in brown soil at various levels of DAP.Increasing non-water-solution phosphates led to increased sorption of copper in brown soil,and enhanced the ability of brown soil to absorb copper.Heavy application of PR had the best effect for increasing sorption of copper in brown soil.It is speculated that DAP was not suitable as a fertilizer in brown soil contaminated with copper in terms of food safety,whileas PR could be a candidate phosphate fertilizer in such soil.