Pendimethalin and oxyfluorfen degradation under two irrigation conditions over four years application

Alister, CA; Gomez, PA; Rojas, S.; Kogan M.

Abstract

A four-year field study was conducted to determine the effect of pluviometric conditions on pendimethalin and oxyfiuorfen soil dynamics. Adsorption, dissipation and soil movement were studied in a sandy loam soil from 2003 to 2007. Pendimethalin and oxyfluorfen were applied every year on August at 1.33 and 0.75 kg ha-1, respectively. Herbicide soil concentrations were determined at 0, 10, 20, 40, 90 and 340 days after application (DAA), under two pluviometric regimens, natural rainfall and irrigated (30 mm every 15 days during the first 90 DAA). More than 74% of the herbicide applied was detected at the top 2.5 cm layer for both herbicides, and none was detected at 10 cm or deeper. Pendimethalin soil half-life ranged from 10.5 to 31.5 days, and was affected mainly by the time interval between application and the first rain event. Pendimethalin soil residues at 90 DAA fluctuated from 2.5 to 13.8% of the initial amount applied, and it decreased to 2.4 and 8.6% at 340 DAA. Oxyfluorfen was more persistent than pendimethalin as indicated by its soil half-life which ranged from 34.3 to 52.3 days, affected primarily by the rain amount at the first rainfall after application. Oxyfiuorfen soil residues at 90 DAA ranged from 16.7 to 34.8% and it decreased to 3.3 and 17.9% at 340 DAA. Based on half-life values, herbicide soil residues after one year, and soil depth reached by the herbicides, we conclude that both herbicides should be considered as low risk to contaminate groundwater. However, herbicide concentration at the top 2.5 cm layer should be considered in cases where runoff or soil erosion could occur, because of the potential for surface water contamination. © Taylor & Francis Group, LLC.

Más información

Título según WOS: Pendimethalin and oxyfluorfen degradation under two irrigation conditions over four years application
Título según SCOPUS: Pendimethalin and oxyfluorfen degradation under two irrigation conditions over four years application
Título de la Revista: JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES
Volumen: 44
Número: 4
Editorial: TAYLOR & FRANCIS INC
Fecha de publicación: 2009
Página de inicio: 337
Página final: 343
Idioma: English
URL: http://www.tandfonline.com/doi/abs/10.1080/03601230902800986
DOI:

10.1080/03601230902800986

Notas: ISI, SCOPUS