The Dissipation of Penoxsulam Herbicide in Flooded Rice Fields. (S11-roberts831870-poster)
Authors:
D. Roberts* - Dow AgroSciences J.A. Knuteson - Dow AgroSciences R. Jackson - Dow AgroSciences
Abstract:
Field dissipation of penoxsulam, a new triazolopyrimidine sulfonamide herbicide for use in rice was investigated in drained or flooded rice fields. In May 2001 at Spain and Italy, the oil dispersible (OD) formulation was applied at 100 g ai/ha to bare soil plots drained at pre-application and re-flooded within one day post-application (1-DAT), typical practice for these areas. In June 2000 at Arkansas (AR) and California (CA), the OD formulation was applied post-emergence at 100 g ai/ha to cropped and bare ground plots, with the AR plots drill-seeded and dry at time of application, then flooded 10-DAT. The CA plots were wet-seeded and in flooded condition at application, typical practice for these areas. In addition, in June 2001 at CA, a granular formulation was applied post-emergence at 57 g ai/ha to a wet-seeded, flooded plot. All test plots were maintained under flooded condition during the summer months. Penoxsulam dissipated rapidly in water at all five sites with first-order field half-life of 3-7 days and DT90 of 10-24 days. Soil residues were low and transient in all flooded plots. At the AR site, where soil was dry for 10-DAT, field soil half-life was 13-16 days. The microbiological degradates 5 hydroxy and BSTCA and photolysis products TPSA and BSA were transient and low-level,
indicating a combination of microbial degradation and photodegradation was responsible for the observed rapid dissipation.
Speaker Information: David Roberts, Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46238;
Phone: 317-337-3477; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 1518)
Keywords: environmental fate of penoxsulam; field dissipation; soil dissipation; rice-field dissipation
