ABSTRACT

To ascertain the effect of biochar on remediation of paddy soil contaminated by heavy metals under different irrigation regimes (flooding irrigation (FI), intermittent irrigation (II) and wet irrigation (WI)), rice straw biochar (RSB) and rice husk biochar (RHB) were applied into soil contaminated by Cd and Cu. The concentrations of available Cd and Cu were significantly reduced by RSB, and decreased by 6.8–15.9%, 11.1–20.0% and 6.8–18.2%, and 6.2–12.9%, 7.0–14.8% and 5.6–17.7% under FI, II and WI regimes, respectively. The application of RHB generally reduced the content of acid extractable and reducible Cd under FI and II regimes, and promoted its transformation to oxidizable and residual form. Similarly, both biochars reduced the acid extractable Cu in paddy soil and promoted its transformation to reducible and oxidizable form under three irrigation regimes (especially in II). This is significantly related to the increase of soil pH, organic matter content and cation exchange capacity by biochar. The preliminary results of this study indicate that biochar application combined with intermittent irrigation could be an effective measure to enhance the paddy soil quality. However, future studies are still needed to evaluate the long-term impact of biochar on heavy metal bioavailability under different water conditions.

摘要

确定生物炭在不同灌溉方式（漫灌（FI）、间歇灌溉（II）和湿灌（WI））、稻草生物炭（RSB）和稻壳生物炭（ RHB）被施用于被 Cd 和 Cu 污染的土壤。RSB 显着降低了有效 Cd 和 Cu 的浓度，在 FI、II 下分别降低了 6.8-15.9%、11.1-20.0% 和 6.8-18.2%，以及 6.2-12.9%、7.0-14.8% 和 5.6-17.7%和 WI 制度，分别。RHB 的应用普遍降低了 FI 和 II 状态下酸可提取和可还原 Cd 的含量，并促进其向可氧化和残留形式的转变。相似地，两种生物炭都减少了水稻土中可酸提取的铜，并促进其在三种灌溉制度下（尤其是在 II 中）向可还原和可氧化形式的转变。这与生物炭提高土壤pH值、有机质含量和阳离子交换能力显着相关。本研究的初步结果表明，生物炭施用与间歇灌溉相结合可能是提高水稻土壤质量的有效措施。然而，未来的研究仍然需要评估生物炭在不同水条件下对重金属生物利用度的长期影响。本研究的初步结果表明，生物炭施用与间歇灌溉相结合可能是提高水稻土壤质量的有效措施。然而，未来的研究仍然需要评估生物炭在不同水条件下对重金属生物利用度的长期影响。本研究的初步结果表明，生物炭施用与间歇灌溉相结合可能是提高水稻土壤质量的有效措施。然而，未来的研究仍然需要评估生物炭在不同水条件下对重金属生物利用度的长期影响。