Sorption and desorption of mesotrione alone and mixed with S-metolachlor+terbuthylazine in Brazilian soils

Publication date: 15 October 2016
Source:Geoderma, Volume 280
Author(s): Kassio Ferreira Mendes, Marcelo Rodrigues dos Reis, Miriam Hiroko Inoue, Rodrigo Floriano Pimpinato, Valdemar Luiz Tornisielo
The mixture of herbicides is a widely used technique in weed control in several crops, including maize. However, interactions that might potentially result from mixing herbicides are a matter of constant concern and research. Soil capacity to retain herbicides directly influences the final destination of these molecules in the environment. The aim of this study was to evaluate sorption and desorption of mesotrione applied alone and mixed with S-metolachlor+terbuthylazine in samples from seven Brazilian sites cultivated with maize. Mesotrione sorption (alone and mixed) was evaluated five concentrations with 0.125, 1.042 and 0.625mgkg⁻¹ corresponding to the field dose of mesotrione, S-metolachlor and terbuthylazine, respectively. Sorption of mesotrione applied alone and mixed had Kd (sorption coefficient) values ranging from 0.08 to 5.05kgL⁻¹ and from 0.09 to 5.20kgL⁻¹, respectively, with similar behavior across soils. Mesotrione sorption was influenced primarily by the clay mineral (CM) content and the soil pH. The mode of application (alone or mixed) did not influence sorption or desorption. Mesotrione sorption was relatively low in soils, which creates the potential for leaching in maize producing areas.