Li Qi, Chang Jingjing, Li Linfeng, Lin Xiaoyang, Li Yichun
Key Laboratory of Plant Nutrition and Fertilizer in South Region, Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation, Institute of Agricultural Resources and Environment, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
Key Laboratory for New Technology Research of Vegetable, Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
Sci Total Environ. 2024 May 10;924:171399. doi: 10.1016/j.scitotenv.2024.171399. Epub 2024 Mar 6.
Soil amendments play a pivotal role in ensuring the safety of food production by inhibiting the transfer of heavy metal ions from soils to crops. Nevertheless, their impact on soil characteristics and the microbial community and their role in reducing cadmium (Cd) accumulation in rice remain unclear. In this study, pot experiments were conducted to investigate the effects of three soil amendments (mineral, organic, and microbial) on the distribution of Cd speciation, organic components, iron oxides, and microbial community structure. The application of soil amendments resulted in significant reductions in the soil available Cd content (16 %-51 %) and brown rice Cd content (16 %-78 %), facilitating the transformation of Cd from unstable forms (decreasing 10 %-20 %) to stable forms (increasing 77 %-150 %) in the soil. The mineral and organic amendments increased the soil cation exchange capacity (CEC) and plant-derived organic carbon (OC), respectively, leading to reduced Cd accumulation in brown rice, while the microbial amendment enhanced OC complexity and the abundances of Firmicutes and Bacteroidota, contributing to the decreased rice Cd uptake. The synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectroscopy indicated that soil amendments regulated soil Cd species by promoting iron oxides and OC coupling. Moreover, both organic and microbial amendments significantly reduced the diversity and richness of the bacterial communities and altered their compositions and structures, by increasing the relative abundances of Bacteroidota and Firmicutes and decreasing those of Acidobacteria, Actinobacteria, and Myxococcota. Soil microbiome analysis revealed that the increase of Firmicutes and Bacteroidota associated with Cd adsorption and sequestration contributed to the suppression of soil Cd reactivity. These findings offer valuable insights into the potential mechanisms by which soil amendments regulate the speciation and bioavailability of Cd, and improve the bacterial communities, thereby providing guidance for agricultural management practices.
土壤改良剂通过抑制重金属离子从土壤向作物的转移，在确保粮食生产安全方面发挥着关键作用。然而，它们对土壤特性和微生物群落的影响以及在减少水稻中镉（Cd）积累方面的作用仍不清楚。在本研究中，进行了盆栽试验，以研究三种土壤改良剂（矿物、有机和微生物）对Cd形态分布、有机成分、铁氧化物和微生物群落结构的影响。施用土壤改良剂导致土壤有效Cd含量（16% - 51%）和糙米Cd含量（16% - 78%）显著降低，促进了土壤中Cd从不稳定形态（降低10% - 20%）向稳定形态（增加77% - 150%）的转化。矿物和有机改良剂分别提高了土壤阳离子交换容量（CEC）和植物源有机碳（OC），导致糙米中Cd积累减少，而微生物改良剂提高了OC复杂性以及厚壁菌门和拟杆菌门的丰度，有助于降低水稻对Cd的吸收。基于同步辐射的傅里叶变换红外光谱（SR - FTIR）表明，土壤改良剂通过促进铁氧化物和OC耦合来调节土壤Cd形态。此外，有机和微生物改良剂均显著降低了细菌群落的多样性和丰富度，并改变了它们的组成和结构，增加了拟杆菌门和厚壁菌门的相对丰度，降低了酸杆菌门、放线菌门和粘球菌门的相对丰度。土壤微生物群落分析表明，与Cd吸附和螯合相关的厚壁菌门和拟杆菌门的增加有助于抑制土壤Cd活性。这些发现为土壤改良剂调节Cd形态和生物有效性以及改善细菌群落的潜在机制提供了有价值的见解，从而为农业管理实践提供指导。
