N、P、K肥对香根草修复土壤镉、锌污染效率的影响

Effects of N,P,K Fertilizer on Phytoremediation Effectiveness of Cadmium and Zinc Pollution in Vetiver Grass

通过盆栽试验研究在30 mg/kg镉(Cd)污染土壤条件下N[CO(NH2)2:100、200、300 mg/kg土]、P(P2O5:50、100、200 mg/kg土)和K(KCl:100、200、300 mg/kg土)处理对香根草修复土壤Cd和锌(Zn)污染效率的影响。结果表明:3种N处理能促进香根草地上部生长,而且显著提高地上部特别是叶的Cd和Zn含量,导致其修复效率成倍显著增加;200 mg/kg K处理显著提高Zn修复效率,但300 mg/kg K和50、200 mg/kg P处理却显著降低Cd、Zn修复效率。因此,为改善香根草对较贫瘠土壤中Cd、Zn污染的修复效率,应对香根草适施N肥,并控制或者不施P、K肥为佳。

Effects of different levels of N [CO （NH2）2 ： 100,200 and 300 mg/kg], P （P2O5：50,100 and 200 mg/kg） and K （KC1.100,200 and 300 mg/kg） treatments on phytoremediation effectiveness of cadmium （Cd） and zinc （Zn） in vetiver grass（Vetiveria zizanioides Nash）growing in Cd contaminated soil （30 mg Cd/kg） were investigated by pot experiment. The results showed that the biomass and contents of Cd and Zn in shoot,especially in leaves, significantly enhanced with three N treatments, which resulted in significant increases in Cd and Zn phytoremediation effectiveness,with the Cd phytoremediation effectiveness being 1.60,2.67 and 2.50 times and the Zn phytoremediation effectiveness being 1.81,2.66 and 2.60 times in 100,200 and 300 mg/kg N, respectively, as compared with the control. Moreover,with 200 mg/kg K treatement,Zn phytoremediation effectiveness also significantly increased without impactment of Cd phytoremediation. However,the phytoremediation effectiveness of Cd and Zn decreased significantly with 50, 200 mg/kg P and 300 mg/kg K treatements,while no significant differences were presented in 100 mg/kg P and 100 mg/kg K treatements respectively. Thus, it was suggested that utilization of N fertilizer rather than P and K could efficiently improve the Cd and Zn phytoremediation effectiveness of vetiver glass under sterile soil.