Water quality of a cereal catchment area. Case study of the Aurade (Gers, France) where grassed buffer strips have been used

appropriate technology bassin versant cereal crops cours d'eau cultivos de cereales cursos de agua eau de ruissellement efficiency eficacia escorrentia lutte antipollution midi pyrenees midi-pyrenees pesticide pesticides plaguicidas pollution control pollution de l'eau residues residuos rivers runoff water pollution watersheds