Evaluation of biochar addition to an agricultural soil on the fate and bioavailability of the herbicide clomazone

Abstract

Three natural smectitic clays (SWy-2, CTI and SH) were modified with one inorganic cation (FE3+) and one biopolymeric (chitosan, ch) cation with the aim to increase the adsorption capacity of those mineral clays for tricyclazole. The sorption capacity of the clays was assessed to increase, with the greatest adsorption (>93%) for natural clays modified with Fe3+ . Three types of clay-tricyclazol complexes (ground mixing, GM; weak complex, WC; and strong complex,SC) were prepared and tested as controlled release formulations (çCRFs). The release of tricyclazole in water decreased from the GMs of the CTIFe (85%), SWch4 (84%) and SWch6 (77%), showing lower values than the commercial product (100%) . Soil leaching depended on the soil type: Triciclazole was not detected in any leachate and alluvial soil, but in the sandy the SWch6 WC reduced tricyclazole leaching (65%) from the commercial formulation (75%). Clay tricyclzol complexes andr shown as usefull CRFs to minimize water contamination potential of this fungicide.