| 生物炭与氮肥复施对镉污染水稻土修复效应及机制 |
| 摘要点击 3363 全文点击 909 投稿时间：2022-08-30 修订日期：2022-11-01 |
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| 中文关键词 生物炭 氮肥 Cd形态 水稻Cd富集转运 酶活性 微生物群落 微生物共现网络 |
| 英文关键词 biochar nitrogen fertilizer Cd fractions rice Cd enrichment and transport enzyme activity bacterial community composition microbial co-occurrence network |
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| 中文摘要 |
| 重金属镉(Cd)污染已严重影响土壤健康,威胁农产品生产安全利用.因此采用盆栽试验,以Cd污染水稻土为供试土壤,研究生物炭(BC)、不同氮肥施用水平2.6 g ·pot-1(N1)、3.5 g ·pot-1(N2)、4.4 g ·pot-1(N3)和生物炭配施氮肥(BCN1、BCN2、BCN3)对土壤Cd形态、水稻体内Cd富集和转运以及土壤酶活性的影响,并通过高通量测序分析土壤微生物菌群变化和微生物间复杂的相互作用关系.结果表明,生物炭配施氮肥处理下土壤Cd由活性较高的可交换态向活性低的残渣态转化,可交换态Cd含量较对照降低了6.2%~14.7%,残渣态Cd含量提高了18.6%~26.4%.单一氮肥处理增强了水稻根部Cd的富集能力,提高了22%~33.5%,单一生物炭和配施氮肥处理下水稻根部Cd的富集能力、Cd从茎叶向稻壳和稻壳向稻米的转运系数均下降.BCN处理总体上促进了土壤酶活性(脲酶、酸性磷酸酶、蔗糖酶和过氧化氢酶),MiSeq测序显示生物炭配施氮肥提高了土壤细菌主要物种相对丰度(如Acidobacteriales、Solibacterales、Pedosphaerales和Nitrospirales),共现网络分析表明N、BC和BCN处理下土壤细菌网络复杂性均增强.总体来看,生物炭配施氮肥降低了土壤Cd活性,抑制了水稻对Cd的富集和转运,一定程度上改善了土壤生态环境质量,为重金属Cd污染农田土壤修复提供了技术支撑. |
| 英文摘要 |
| Cadmium (Cd) heavy metal pollution has posed serious threats to soil health and the safe production utilization of agricultural products. A pot experiment was conducted to study the effects of biochar (BC) and nitrogen fertilizer with three levels, namely 2.6 g·pot-1 (N1), 3.5 g·pot-1 (N2), 4.4 g·pot-1 (N3) biochar combined with nitrogen fertilizer (BCN1, BCN2, and BCN3), on soil Cd fractions, Cd enrichment, the transport of rice, and soil enzyme activity, as well as the changes in microbial community composition and complex interactions between microorganisms through high-throughput sequencing. The results showed that biochar combined with nitrogen fertilizer led to the transformation of Cd from the exchangeable state to the residue state, and the proportion of the exchangeable state was significantly reduced by 6.2%-14.7%; by contrast, the proportion of the residue state increased by 18.6%-26.4% relative to that in CK. In addition, singular treatments of nitrogen fertilizer enhanced the accumulation capacities of Cd in roots, which increased by 22%-33.5% compared with that in CK. By contrast, the BC and BCN treatments reduced Cd accumulation in roots and the transfer capacity from stems to rice husks and husk to rice. Furthermore, the BCN treatments promoted soil enzyme activities (urease, acid phosphatase, invertase, and catalase). MiSeq sequencing showed that BCN treatments increased the abundance of the main species of soil bacterial microbes (such as Acidobacteriales, Solibacterales, Pedosphaerales, and Nitrospirales). Moreover, co-occurrence network analysis showed that the complexity of the soil bacterial network was enhanced under the N, BC, and BCN treatments. Overall, biochar combined with nitrogen fertilizer reduced soil Cd availability, inhibited the capacity of Cd accumulation and the transport of rice, and improved the soil eco-environmental quality. Thus, using BCN could be a feasible practice for the remediation of Cd-polluted agricultural soil. |
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