Sorption and desorption of glyphosate in Mollisols and Ultisols soils of Argentina

In Argentina, glyphosate use has increased exponentially in recent years as a result of the widespread adoption of no‐till management combined with genetically modified glyphosate‐resistant crops. This massive use of glyphosate has created concern about its potential environmental impact. Sorption–desorption of glyphosate was studied in 3 Argentinean soils with contrasting characteristics. Glyphosate sorption isotherms were modeled using the Freundlich equation to estimate the sorption coefficient (Kf). Glyphosate sorption was high, and the Kf varied from 115.6 to 1612 mg1–1/nL1/n/kg. Cerro Azul soil had the highest glyphosate sorption capacity as a result of a combination of factors such as higher clay content, cation exchange capacity, total iron, and aluminum oxides, and lower available phosphorus and pH. Desorption isotherms were also modeled using the Freundlich equation. In general, desorption was very low (