[Effects and Mechanisms of Organic Fertilizer on the Accumulation and Transport of Arsenic and Cadmium in the Soil-rice System].
Source: PubMed, NCBI / U.S. National Library of Medicine
A field experiment of paddy soil co-contaminated by As-Cd in Hunan Province was conducted to study the role of organic fertilizers in simultaneously regulating As and Cd uptake by rice grain. This research investigated the effects of different application levels of commercial organic fertilizer (OF) and milk vetch (MV) on soil physicochemical properties, root iron plaque, rhizosphere soil microbial community structure, and content and translocation of As-Cd in rice. The results showed that soil pH and the availability of As and Cd in soil from the OF treatment was improved, whereas the available Cd content from a high level of MV addition treatment was significantly reduced by 12.0%-12.9% (<0.05). Organic fertilizer treatments enhanced iron plaque formation and content of As and Cd in the iron plaque. The As and Cd content in brown rice from the OF and MV treatment was significantly decreased by 10.9%-17.4% and 14.3%-47.6%, respectively, compared with that in the control treatment. The translocation factors of As (As-TF) and Cd (Cd-TF) from organic fertilizer treatments were significantly decreased (0.05), and the content of inorganic As and Cd in brown rice were below the limits listed in the National Food Safety Standard for Contaminants in Food (GB 2762-2022). Brown rice As content was significantly negatively correlated with Fe content in iron plaque and significantly positively correlated with As-TF, whereas rice Cd content was significantly negatively correlated with
Abstract
A field experiment of paddy soil co-contaminated by As-Cd in Hunan Province was conducted to study the role of organic fertilizers in simultaneously regulating As and Cd uptake by rice grain. This research investigated the effects of different application levels of commercial organic fertilizer (OF) and milk vetch (MV) on soil physicochemical properties, root iron plaque, rhizosphere soil microbial community structure, and content and translocation of As-Cd in rice. The results showed that soil pH and the availability of As and Cd in soil from the OF treatment was improved, whereas the available Cd content from a high level of MV addition treatment was significantly reduced by 12.0%-12.9% (<0.05). Organic fertilizer treatments enhanced iron plaque formation and content of As and Cd in the iron plaque. The As and Cd content in brown rice from the OF and MV treatment was significantly decreased by 10.9%-17.4% and 14.3%-47.6%, respectively, compared with that in the control treatment. The translocation factors of As (As-TF) and Cd (Cd-TF) from organic fertilizer treatments were significantly decreased (0.05), and the content of inorganic As and Cd in brown rice were below the limits listed in the National Food Safety Standard for Contaminants in Food (GB 2762-2022). Brown rice As content was significantly negatively correlated with Fe content in iron plaque and significantly positively correlated with As-TF, whereas rice Cd content was significantly negatively correlated with Cd content in iron plaque and significantly positively correlated with Cd-TF(<0.05). These results indicated that organic fertilizer application reduced As-Cd content in brown rice through inhibiting As uptake by roots, as well as promoting Cd immobilization in iron plaque and inhibiting its transport from shoot to grain. RDA analysis revealed that brown rice As and Cd content was positively correlated with relative abundance of Chloroflexi, suggesting that organic fertilizer application simultaneously reduced As-Cd accumulation in brown rice through decreasing Chloroflexi abundance. These findings provide a technical base for organic fertilizer regulation of As-Cd content in rice grain.