Department of Environmental Science & Engineering, School of Energy & Environment, Anhui University of Technology, Maanshan, 243002, China.
Key Laboratory for Crop & Animal Integrated Farming of Ministry of Agriculture & Rural Affairs, Institute of Agricultural Resources & Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
J Environ Manage. 2023 Sep 15;342:118135. doi: 10.1016/j.jenvman.2023.118135. Epub 2023 May 20.
Rice grown on Cd-contaminated soil may accumulate Cd in grain, which is extremely harmful to human health. Several managements are developed to reduce the Cd load in rice, while in-situ immobilization by soil amendments has been attractive for its feasibility. Waste-derived hydrochar (HC) has been shown effective at immobilizing Cd in soil. However, potential plant negative effects and huge application amount are crucial to resolving in extensive application of HC. Nitric acid ageing may be an effective method to deal with these problems. In this paper, HC and nitrated hydrochar (NHC) were added to the Cd-contaminated soil at rates of 1% and 2% in a rice-soil column experiment. Results showed that NHC markedly promoted root biomass of rice by 58.70-72.78%, whereas HC had effects of 35.86-47.57%. Notably, NHC at 1% reduced the accumulation of Cd in rice grain, root and straw by 28.04%, 15.08% and 11.07%, respectively. A consistent decrease of 36.30% in soil EXC-Cd concentration was caused by NHC-1%. Following soil microbial community was shifted greatly under HC and NHC applications. The relative abundance of Acidobacteria was decreased by 62.57% in NHC-2% and by 56.89% in HC-1%. Nevertheless, Proteobacteria and Firmicutes were promoted by NHC addition. In contrast to HC, co-occurrence network of dominated bacteria was more complex and centralized generated by NHC. Key bacteria in that metabolic network of NHC such as Anaerolineae and Archangiaceae played key roles in Cd immobilization. These observations verified that NHC was more efficient to decrease Cd accumulation in rice and could alleviate the negative roles to plant by microbial changings in community composition and network. It could provide an enrichment of paddy soil microbial responds to the interaction of NHC with Cd and lay a foundation for the remediation of Cd-contaminated soil by NHC.
在镉污染土壤上种植的水稻可能会在其谷物中积累镉，这对人类健康极其有害。人们开发了几种管理方法来减少水稻中的镉负荷，而原位土壤改良剂固定化因其可行性而受到关注。已证明来源于废物的水热炭（HC）有效地固定土壤中的镉。然而，其对植物的潜在负面影响和巨大的应用量是限制 HC 广泛应用的关键。硝酸老化可能是解决这些问题的有效方法。在这项研究中，采用水稻-土壤柱实验，将 HC 和硝化水热炭（NHC）以 1%和 2%的比例添加到镉污染土壤中。结果表明，NHC 显著促进了水稻根系生物量，增幅为 58.70-72.78%，而 HC 的作用为 35.86-47.57%。值得注意的是，NHC 以 1%的比例降低了水稻籽粒、根和秸秆中 Cd 的积累，分别减少了 28.04%、15.08%和 11.07%。NHC-1%使土壤 EXC-Cd 浓度降低了 36.30%。HC 和 NHC 应用后，土壤微生物群落发生了很大变化。NHC-2%中 Acidobacteria 的相对丰度下降了 62.57%，HC-1%中下降了 56.89%。然而，NHC 的添加促进了 Proteobacteria 和 Firmicutes。与 HC 相比，NHC 产生的优势菌共发生网络更加复杂和集中。NHC 代谢网络中的关键细菌，如 Anaerolineae 和 Archangiaceae，在 Cd 固定化中发挥了关键作用。这些观察结果证实，NHC 能更有效地降低水稻对 Cd 的积累，通过改变群落组成和网络，减轻其对植物的负面影响。它可以为富含水稻土壤微生物对 NHC 与 Cd 相互作用的响应提供依据，为 NHC 修复镉污染土壤奠定基础。
