NO_(3)^(-)-N和NH_(4)^(+)N联合生物炭对黑麦草修复镉污染的影响

Effects of NO_(3)^(-)-N and NH_(4)^(+)-N combined biochar on Cd remediation by ryegrass

为降低土壤中镉(Cd)的危害,研究探讨了生物炭配施氮肥对黑麦草富集Cd的影响。采用盆栽实验研究土壤Cd污染水平(0.3,3,5 mg/kg)、氮肥形态(硝酸盐氮和铵态氮)、氮肥水平(0.1,0.2,0.5,1 g/kg)对Cd形态和黑麦草富集的影响。结果表明,单施生物炭可以固定土壤中游离的Cd,相比NH_(4)^(+)-N,配施NO_(3)^(-)-N黑麦草对Cd的吸收、迁移和富集能力更强。不同Cd污染浓度下,不同NO_(3)^(-)-N水平下Cd的最大去除率分别可以达到30.23%,36.06%和30.90%;不同NH_(4)^(+)-N水平下,Cd的最大去除率可以达到24.49%,28.05%和24.79%。结合相关性分析表明,pH对Cd形态变化和Cd的富集起着关键性作用,且生物炭与NO_(3)^(-)-N的配施可以更有效、快捷地降低土壤中的Cd,更利于Cd污染土壤的安全应用。

The effects of nitrogen fertilizer and biochar on ryegrass Cd enrichment were examined in order to lessen the harm caused by cadmium(Cd)in soil.The effects of soil Cd pollution levels(0.3,3,5 mg/kg),nitrogen fertilizer forms(nitrate nitrogen and ammonium nitrogen)and nitrogen fertilizer levels(0.1,0.2,0.5,1 g/kg)on Cd forms and ryegrass enrichment were studied in pot experiment.According to the findings,biochar alone might repair free Cd in soil,compared to NH_(4)^(+)-N,combined application of NO_(3)^(-)-N ryegrass has a stronger ability to absorb,migrate and enrich Cd.Under different Cd pollution concentrations,the maximum removal rates of Cd under different NO_(3)^(-)-N levels could reach 30.23%,36.06%and 30.90%,respectively,while the maximum removal rates of Cd under different NH_(4)^(+)-N levels could reach 24.49%,28.05%and 24.79%.Combined correlation analysis revealed that pH played a significant role in the change of Cd morphology and Cd enrichment.When biochar and NO_(3)^(-)-N were applied together,the content of Cd in the soil could be reduced more quickly and effectively,which was better suited for the safe application of Cd-polluted soil.