Glyphosate effects on non-target plants: collateral impacts on elemental composition and growth of yerba mate

Authors: MAGRI, EDERLAN - Federal University Of Parana Polytechnic Center; BARBOSA, JULIERME - Federal University Of Minas Gerais; Prior, Stephen - Steve; VALDUGA, ALICE - Regional Integrated University Of Alto Uruguai And Missões(URI); MOTTA, ANTONIO - Federal University Of Parana Polytechnic Center

Submitted to: Archives of Agronomy and Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2022
Publication Date: 4/27/2023
Citation: Magri, E., Barbosa, J.Z., Prior, S.A., Valduga, A.T., Motta, A.C. 2023. Glyphosate effects on non-target plants: collateral impacts on elemental composition and growth of yerba mate. Archives of Agronomy and Soil Science . 69(9):1535-1547. https://doi.org/10.1080/03650340.2022.2102610.
DOI: https://doi.org/10.1080/03650340.2022.2102610

Interpretive Summary: Yerba mate leaves (Ilex paraguariensis) are used in infusion beverages and contain elements of interest to human health. Leaf element composition can vary with native soils and farm practices. This work investigated glyphosate use, soil type, phosphorus fertilization for two mate cultivars. Findings showed that use of glyphosate to control unwanted plants can harm initial plant development on P-deficient soils, with distinct effects noted between cultivars and type of soil in which plants were grown. Elemental composition of leaves can be altered, as seen by increases in some elements that differed between cultivars and soil type. Regarding the potentially toxic elements Cd and Pb, there were small increases in some cases, but these changes were not expressive to point of being a matter of concern to producers and consumers.

Technical Abstract: This work investigated collateral effects on non-target yerba mate (Ilex paraguariensis A. St.-Hil) plants when using glyphosate for weed control; growth and leaf elemental composition were examined. Special emphasis was place on examining the heavy metals Cd and Pb due to regulations defining maximum limits in South American infusion products. The experiment was conducted in pots using glyphosate [applied to Congo grass (Brachiaria ruziziensis), soil surface and control], two P rates (with and without P), two clonal yerba mate cultivars, and two different soils (basalt- and rhyodacite-derived). When used to control Congo grass, glyphosate reduced total dry matter and base diameter of yerba mate plants; effects were enhanced by lack of P in soil and differed between clones and soils. Collateral effects of glyphosate use resulted in increased K, P, and Cu in one clone cultivated in basalt soil and increase levels of Ca, Mg, Mn, Fe and Zn in clone 1 and B, Cd and Pb in clone 2 when cultivated in rhyodacite soil. These observations demonstrate that glyphosate use to control undesirable plants can impact initial development and elemental composition of yerba mate, with variations between cultivars and soil type.