Influência do pH na adsorção de glifosato em solos com incremento de ácidos húmicos de diferentes origens

Abstract

Humic acids (HAs) are substances present in vast amounts in the environment. Its structural relationship with soil conservation and its origin in addition to its great adsorption capacities are studied in several areas. Glyphosate is the most widely used agrochemical in Brazil, however, as a consequence, its environmental risk must be better evaluated. When it comes to the ability of HAs to inactivate agrochemicals such as glyphosate, studies show an effective action in preventing its leaching, but it is relevant to evaluate the different pH conditions in which they occur. This work evaluated the differences between HAs from native forest regions and cultivated areas, with and without erosion control, in addition to verifying the impact generated by differences in the pH of the medium. The tests were carried out in fixed bed columns, simulating a real application of the agrochemical and evaluating the posterior insertion of HAs. The analyzes demonstrated the efficiency of HAs in adsorbing glyphosate at pH 5 and 9, doubling the amount adsorbed in relation to assays without its presence, in pH there was also a significant increase. As for the different management areas, HA from areas with erosion control were superior when compared to those without control, both were less effective than the HA from native forest.