稻秆炭与巨菌草联合对铜镉污染土壤的修复

通过野外小区试验施加不同用量(0、5000、10000、15000、20000 kg·hm^-2)的稻秆生物炭(稻秆炭),探究施用稻秆炭对巨菌草修复铜镉复合(Cu-Cd)污染土壤的影响,并评价稻秆炭与巨菌草联合修复重金属污染土壤的潜力和优势。结果表明,稻秆炭施用可明显提高巨菌草在Cu-Cd污染土壤中的成活率,提高其地上生物量;稻秆炭的施用降低了土壤有效态Cu、Cd和全量Cd含量,在一定程度上降低了巨菌草对Cu的富集,但同时促进了巨菌草对Cd的富集,于5000 kg·hm^-2处理下增幅最大,其根、茎、叶的Cd吸收量分别增加60.75%、230.31%和83.34%;稻秆炭施用显著增加了巨菌草地上部重金属绝对富集量,Cu最高达3741.04 g·hm^-2(用量为10000 kg·hm^-2),Cd最高达167.81 g·hm^-2(用量为5000 kg·hm^-2);各处理的修复边际效率显示,5000 kg·hm^-2稻秆炭施用量更经济、有效。研究表明,稻秆炭施用提升了巨菌草地上部对Cu、Cd的富集水平,其联合修复潜力巨大。

Effect of combination of rice-straw biochar and Pennisetum sinese on remediating Cu and Cd contaminated soil

Herein, a field plot experiment was conducted to investigate the effect of rice-straw biochar application on the Pennisetum sinese remediating the Cu- and Cd-contaminated soil by setting up different application amounts of rice-straw biochar(0, 5 000, 10 000, 15 000 kg·hm^-2, and 20 000 kg·hm^-2), with an aim to evaluate the potential and advantage of the combined remediation of rice-straw biochar and Pennisetum sinese. The results showed that the rice-straw biochar application significantly increased the survival and shoot biomass of Pennisetum sinese in the Cu- and Cd-contaminated soil. Furthermore, the application decreased the available Cu and Cd and the total Cd in soil, and lowered the Cu bioconcentration to some extent; however, it increased the Cd bioconcentration in the Pennisetum sinese. The 5 000 kg·hm^-2 biochar treatment made the biggest Cd gains in root, stem, and leaf of Pennisetum sinese, wherein the increases were 60.75%, 230.31%, and 83.34%, respectively. Additionally, the biochar application significantly promoted the absolute enrichment of Cu and Cd in Pennisetum sinese shoot, wherein the biggest increases were up to 3 741.04 g·hm^-2 with a 10 000 kg·hm^-2 treatment and 167.81 g·hm^-2 with a 5 000 kg·hm^-2 treatment, respectively. Results suggest that 5 000 kg·hm^-2 of rice-straw biochar application amount is more economical and effective according to the marginal efficiency of remediation. The application of rice-straw biochar enhanced the bioconcentration level of the Cu and Cd in the Pennisetum sinese shoot and showed a great remediation potential for Cu- and Cdcontaminated soil.