The role of land use, management, and microbial diversity depletion on glyphosate biodegradation in tropical soils

• Published in: Environmental research 2023-08, Vol.231 (Pt 1), p.116178-116178, Article 116178
• Main Authors: Martins, Guilherme Lucio, de Souza, Adijailton Jose, Osti, Júlio Flavio, Gontijo, Júlia Brandão, Cherubin, Maurício Roberto, Viana, Douglas Gomes, Rodrigues, Mayra Maniero, Tornisielo, Valdemar Luiz, Regitano, Jussara Borges
• Format: Article
• Language: English
• Subjects: Agriculture; Bacteria - genetics; Bacteria - metabolism; Biodegradation; Biodiversity depletion; Ecosystem; Ecosystem services; Glyphosate; Herbicide degradation; High-throughput sequencing; Soil; Soil health; Soil Microbiology
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2023.116178

Land use and management changes affect the composition and diversity of soil bacteria and fungi, which in turn may alter soil health and the provision of key ecological functions, such as pesticide degradation and soil detoxification. However, the extent to which these changes affect such services is still poorly understood in tropical agroecosystems. Our main goal was to evaluate how land-use (tilled versus no-tilled soil), soil management (N-fertilization), and microbial diversity depletion [tenfold (D1 = 10−1) and thousandfold (D3 = 10−3) dilutions] impacted soil enzyme activities (β-glycosidase and acid phosphatase) involved in nutrient cycles and glyphosate mineralization. Soils were collected from a long-term experimental area (35 years) and compared to its native forest soil (NF). Glyphosate was selected due to its intensive use in agriculture worldwide and in the study area, as well as its recalcitrance in the environment by forming inner sphere complexes. Bacterial communities played a more important role than the fungi in glyphosate degradation. For this function, the role of microbial diversity was more critical than land use and soil management. Our study also revealed that conservation tillage systems, such as no-tillage, regardless of nitrogen fertilizer use, mitigates the negative effects of microbial diversity depletion, being more efficient and resilient regarding glyphosate degradation than conventional tillage systems. No-tilled soils also presented much higher β-glycosidase and acid phosphatase activities as well as higher bacterial diversity indexes than those under conventional tillage. Consequently, conservation tillage is a key component for sustaining soil health and its functionality, providing critical ecosystem functions, such as soil detoxification in tropical agroecosystems. [Display omitted] •Bacteria play more important role than fungi on glyphosate degradation.•Soils with high organic loads present higher enzymatic activities.•Microbial diversity is more critical for glyphosate degradation than land use.•No-till and native forest soils can degrade glyphosate even at low diversity levels.•Soil conservation is a key component for sustaining soil health and functionality.