Agricultural practices and environmental consequences: first results

Abstract

We are trying to relate agricultural practices and water quality on a watershed. After less than one year of work, some first resultats are presented. Inquiries have permitted a global approach of supplies and gave an idea of the amounts of potentially polluting substances spread on the fields. But the comparison between excess of nutrients between the usual supplies and outputs by crops or animals and the fluxes of nutrients measured at the outlet has shown high differences, suggesting that physical processes such as volatilisation of ammonia, denitrification, storages in the soils, have an important influence. Agricultural practices registration suggests that for most of the farms important differences of practices occur between fields : a global balance at the farm scale won't be precise enough for pollution diagnosis.