Agron. Sustain. Dev. 25 (2005) 309-315
DOI: 10.1051/agro:2005011

Bentazone adsorption and desorption on agricultural soils

Arnaud Boivin^{a, b}, Richard Cherrier and Michel Schiavon

^a  Present Address: George E. Brown Jr. Salinity Laboratory, USDA-ARS, 450 West Big Springs Road, Riverside, CA 92507-4617, USA
^b  Laboratoire Sols et Environnement, UMR 1120 INPL/ENSAIA-INRA, 2 avenue de la Forêt de Haye, BP 172, 54505 Vandoeuvre-lès-Nancy Cedex, France

(Accepted 3 January 2005)

Abstract - Herbicide fate and transport in soils greatly depend upon adsorption-desorption processes. Batch adsorption and desorption experiments were performed with the herbicide bentazone using 13 contrasted agricultural soil samples. Bentazone was found to be weakly sorbed by the different soils, showing average Freundlich adsorption coefficients (Kf) value of 1.4 ± 2.3 mg^{1 - n_f} L^n_f kg^-1. Soil organic matter content did not have a significant effect on bentazone sorption (r² = 0.12), whereas natural soil pH appeared to be a key factor (r² = 0.68). A large part (average of 96.9 ± 4.1%) of the sorbed bentazone was released into aqueous solution after successive desorption steps, although some hysteresis was observed for each soil. Whereas soil pH was found to also influence bentazone desorption, other soil properties did not show well-defined relationships with sorption.

Key words: bentazone / adsorption / desorption / pH

Corresponding author: Arnaud Boivin aboivin@ussl.ars.usda.gov

© INRA, EDP Sciences 2005