Stabilized Organic Matter Quantities May Strongly Affect the Mobility of Glyphosate into Soil

Abstract

Glyphosate [N-(phosphonomethyl) glycine] is an enzyme inhibiting herbicide, which is widely used in the world. Here, we investigate the glyphosate adsorption potential in tropical soils with pH close to 5. The herbicide was determined via HPLC with detection by UV-Vis. Our results suggest that glyphosate interacts especially with the stabilized organic matter. Thus, even with large amounts of soil organic matter, the soils may not be as effective in the adsorption of the herbicide if they do not also possess high percentage of humic substances. These data are worth far as it allows us to speculate on glyphosate interaction mechanism with the humic substances in slightly acid medium, in addition, also enable us to propose the use of that fraction of the organic matter to immobilize part of the herbicide in the soil and inhibiting its leaching into water bodies.