生物炭对灰漠土铬Cr(Ⅲ)污染的钝化及生物有效性的影响

灰漠土铬Cr(Ⅲ)污染严重影响土壤生物活性,为探索灰漠土铬污染修复的有效方法。采用盆栽试验,探究生物炭对土壤铬污染的钝化效果及其生物有效性的影响。结果表明：施用生物炭显著降低了铬污染土壤中水溶态铬、交换态Cr的含量(P<0.05),同时明显增加还原态铬的含量(P<0.05),生物活性系数随着产炭温度的下降也明显下降(P<0.05),降幅分别为26.70%、41.15%、59.45%。不同炭处理显著降低了玉米籽粒、根、茎、叶的铬含量(P<0.05),尤其是显著降低玉米植株对铬的富集系数(P<0.05),其中高温所产生的生物炭(BC600)能显著减缓Cr污染所造成的生长抑制,能明显增加玉米生物量(P<0.05),但生物量与CK比较无显著差异(P<0.05),且各部分Cr含量小于5 mg/kg,符合饲料原料Cr安全标准。该研究结果可为灰漠土铬污染的修复提供理论依据。

Effect of Biochar on Passivation and Bioavailability of Cr (Ⅲ) Pollution in Grey Desert Soil

The chromium Cr(Ⅲ) pollution of grey desert soil seriously affects the biological activity of the soil. To explore an effective method for the remediation of grey desert soil chromium pollution, a pot experiment was used to explore the effect of biochar application on soil chromium pollution and its bio-availability. The results showed that the application of biochar could significantly reduce the content of water-soluble chromium and the exchanged Cr of chromium-contaminated soil (P<0.05), simultaneously increased the content of reduced chromium (P<0.05). The biological activity coefficient decreased with the increase of temperature (P<0.05), and the decline amplitude was 26.70%, 41.15% and 59.45% respectively. Different biochar treatments significantly reduced the chromium content of corn grains, roots, stems and leaves (P<0.05), especially the chromium enrichment coefficient of corn plants (P<0.05), among which the biochar BC600 produced by high temperature could significantly slow down the growth inhibition caused by Cr pollution, and could significantly increase corn biomass (P<0.05), however the biomass had no significant difference compared with CK (P<0.05). Compared with the addition of chromium alone, the Cr content in maize tissue of BC600 treatment was less than 5 mg/kg, which conformed to the Cr safety standards for feed ingredients. The results could provide a theoretical basis for the soil restoration after chromium pollution in grey desert soil.