Characterization of the Herbicides Adsorption on Lateritic Soils and Their Colloidal Components

ROMINA C. PESSAGNO; ESTEFANIA GONZLEZ SOLVEYRA; MARIA DOS SANTOS AFONSO

Foz de Iguazú

Conferencia; 11th International Conference on surface and colloid science; 2003

Glyphosate is a postemergent herbicide widely used around the world. It is a non-selective herbicide being increasingly used to control annual and perennial weeds. This herbicide is used on many foods and non-foods crops as well as non-crop areas such as roadsides. When it is applied at lower rates, it serves as a plant growth regulator. Glyphosate is immobilized in soils due to the formation of surface complexes with the metal ions. Glyphosate adsorbs onto goethite, clays and soils at several pH values. The phosphonate group is the responsible for the strong adsorption of glyphosate surface complexes. The surface recovery and the adsorption isotherm of this herbicide on soil fractions from different provinces of Argentina (Santa Cruz, Misiones and Corrientes) were evaluated. The characterization of the surface adsorption of the herbicide on the pure minerals that compounds those soils and the soils themselves was done by different analytical methods being the microelectrophoresis one of them. Also, the study of the organic matter content influence on the adsorption process onto lateritic soils from agentinean mesopotamic provinces (Misiones and Corrientes) was done.