Soil sorption and leaching of active ingredients of Lumax® under mineral or organic fertilization

The study describes the soil sorption of the herbicide Lumax(R), composed of S-metolachlor (MTC), terbuthylazine (TBZ), and mesotrione (MST), as influenced by mineral and organic fertilizers. The investigation was performed on a sandy soil of an agricultural area designated as a Nitrate Vulnerable Zone, where mineral and organic fertilizers were applied for many years. Two organic fertilizers, cattle manure and slurry, respectively, and a mineral fertilizer with a nitrification inhibitor, Entec(R), were compared. According to the experiments, performed with a batch method, the sorption conformed to Freundlich model. The extent of sorption of Lumax(R) ingredients was closely related to their octanol-water partition coefficient K-ow. The respective desorption was hysteretic. Leaching trials were carried out by using water or solutions of DOM or Entec(R) as the eluants. Only the elution with the mineral fertilizer promoted the leaching of Lumax(R) active ingredients. (C) 2014 Elsevier Ltd. All rights reserved.