Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture (CENA), University of São Paulo (USP), Av. Centenário, N° 303, Piracicaba, São Paulo, 13400-970, Brazil; School of Environmental Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Department of Agronomy, Federal University of Viçosa, Avenida Peter Henry Rolfs, S/n, Viçosa, Minas Gerais, 36570-000, Brazil.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111222. doi: 10.1016/j.ecoenv.2020.111222. Epub 2020 Sep 2.
Sulfometuron-methyl is a broad-spectrum herbicide, used throughout Brazil; however, its environmental impacts in biochar (BC) amended soils is not fully understood. Biochar is known to enhance soil quality but can also have undesired effects such as altering the bioavailability and behavior of herbicides. Microbial communities can degrade herbicides such as sulfometuron-methyl in soils; however, they are known to be affected by BC. Therefore, it is important to understand the tripartite interaction between these factors. This research aimed to evaluate the sorption-desorption and biodegradation of sulfometuron-methyl in Amazonian soils amended with BC, and to assess the effects of the interactions between BC and sulfometuron-methyl on soil bacterial communities. Soil samples were collected from field plots amended with BC at three doses (0, 40 and 80 t ha) applied ten years ago. The herbicide sorption and desorption were evaluated using a batch equilibrium method. Mineralization and biodegradation studies were conducted in microcosms incubated with C-sulfometuron-methyl for 80 days. Systematic soil sampling, followed by DNA extraction, quantification (qPCR) and 16S rRNA amplicon sequencing were performed. The presence of BC increased the sorption of the herbicide to the soil by 11% (BC40) and 16% (BC80) compared to unamended soil. The presence of BC also affected the degradation of C-sulfometuron-methyl, reducing the mineralization rate and increasing the degradation half-life times (DT50) from 36.67 days in unamended soil to 52.11 and 55.45 days in BC40 and BC80 soils, respectively. The herbicide application altered the bacterial communities, affecting abundance and richness, and changing the taxonomic diversity (i.e., some taxa were promoted and other inhibited). A tripartite interaction was found between BC, the herbicide and soil bacterial communities, suggesting that it is important to consider the environmental impact of soil applied herbicides in biochar amended soils.
甲磺胺隆甲基是一种广谱除草剂，在整个巴西都有使用；然而，其在生物炭（BC）改良土壤中的环境影响还不完全清楚。生物炭已知可以提高土壤质量，但也可能产生不良影响，例如改变除草剂的生物利用度和行为。微生物群落可以降解土壤中的除草剂，如甲磺胺隆甲基；然而，它们已知会受到 BC 的影响。因此，了解这些因素之间的三方相互作用很重要。本研究旨在评估在巴西亚马逊地区添加 BC 的土壤中甲磺胺隆甲基的吸附-解吸和生物降解，并评估 BC 和甲磺胺隆甲基之间的相互作用对土壤细菌群落的影响。土壤样品取自十年前添加 BC 的田间试验区，BC 添加量分别为 0、40 和 80 t ha。使用批量平衡法评估了除草剂的吸附和解吸。在含有 C-甲磺胺隆甲基的微宇宙中进行了矿化和生物降解研究，培养 80 天。进行了系统的土壤采样，随后进行 DNA 提取、定量（qPCR）和 16S rRNA 扩增子测序。与未添加 BC 的土壤相比，BC 的存在使除草剂的土壤吸附增加了 11%（BC40）和 16%（BC80）。BC 的存在还影响了 C-甲磺胺隆甲基的降解，降低了矿化率，并将降解半衰期（DT50）从未添加 BC 的土壤中的 36.67 天分别延长至 BC40 和 BC80 土壤中的 52.11 和 55.45 天。除草剂的应用改变了细菌群落，影响了丰度和丰富度，并改变了分类多样性（即，一些分类群受到促进，而其他分类群受到抑制）。发现 BC、除草剂和土壤细菌群落之间存在三方相互作用，这表明在生物炭改良土壤中考虑土壤施加的除草剂的环境影响很重要。
