Untersuchungen Zum Einfluss einer Pflanzenscutzmittelspritzfolge auf das Rückstandsverhalten von Terbutryn und die mikrobielle Aktivität im Boden. Teil I. Rückstandsverhalten von Terbutryn

Studies on the effect of a pesticides spray sequence on the behaviour of terbutryn residues and on soil microbial activity. Part I. Behaviour of terbutryn residues In laboratory incubation studies (at 10 and 20°C and 30 and 60% soil water-holding capacity) terbutryn dissipated with half lives of 19–113 days at a standard rate of application (2·09 or 2·8mg kg^?1) and 62–258 days at a 10-fold higher rate. There was little difference between two soils of different sorptive properties. The water-extractable residues showed that terbutryn was extensively adsorbed by both soils with only 12–18%‘plant-available'. Persistence of terbutryn in the field was consistent with the laboratory results and was predicted satisfactorily with a mathematical simulation model. In the laboratory, terbutryn breakdown was inhibited by the simultaneous application of dinoseb acetate and stimulated by triadimefon and parathion but these results were not confirmed in the field.