Boletín de la Sociedad Geológica Mexicana Volumen 67, núm. 3, 2015, p. 509-516 http://dx.doi.org/10.18268/BSGM2015v67n3a13

pH dependence of Glyphosate adsorption on soil horizons

Hector R. Tévez¹, Maria dos Santos Afonso^2,*

¹ Facultad de Ciencias Forestales, Universidad Nacional de Santiago del Estero. Avenida Belgrano Sur 1912. 4200 Santiago del Estero, Argentina.
² INQUIMAE, Facultad de Ciencias Exactas y Naturales- Universidad de Buenos Aires. Ciudad Universitaria, Pabellón II, 3er Piso, Ciudad Autónoma de Buenos Aires, C1428EHA, Argentina.

^* This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Pesticides bring many problems to the environment and to human health. The first rationale for their use is increased food production. Glyphosate N-(phosphonomethyl)glycine (PMG) is a non-selective, post emergent, and broad spectrum herbicide, very well known for its extensive application in agriculture worldwide. PMG adsorption experiments were carried out in three horizons of a Typic Haplustoll soil from the Province of Santiago del Estero, Argentina.

Adsorption isotherms were fitted using Freundlich and Langmuir models. The affinity constants (K_F and K_L), the adsorption intensity (1/n) and the maximum surface coverage (Γ_max) were obtained. The results show the dependence of the parameters K_L and Γ_maxwith pH and also with the different horizons and particle size.

Keywords: Glyphosate, Adsorption isotherm, horizon, profile.