Une approche interdisciplinaire, pluri-échelle, multipartenaire des pollutions diffuses de l'eau : l'expérience de La Côte Saint-André (Isère)

An interdisciplinary, pluriscale and pluripartner approach of water non-point- source pollutions: the La Côte Saint-André experience

¹ Laboratoire d'Economie et de Sociologie Rurales, INRA/R&A, Université Pierre Mendès France, Grenoble
² ISARA-Lyon, INRA-Laon, Unité d'Agronomie
³ Laboratoire d'étude des Transferts en Hydrologie et Environnement, CNRS, INPG, Université Joseph Fourier, Grenoble
⁴ Lycée d'Enseignement Général et Technique Agricole, La Côte-Saint-André

Abstract

The Bievre-Liers plain (300 km²) surrounding the La Côte Saint André district represents a region of intensive agriculture where the nitrate concentration in the aquifer which regularly increases since the mid Seventies, threatens to go beyond the European limit of 50 mg l^-1. Within this contex a multidisdplinary and pluriannual scientific programme has been set up in 1991. By associating several academic research teams, local authorities as well as farmers, its objectives were oriented towards the development of an agriculture more concerned by groundwater quality, but still profitable. The paper presents a brief summary of the main results which have been obtained after a 4 year period of intensive field work. Three spatial scales are considered:

- the field plot ranging from 1 m² to 1 ha for studying the detailed processes occuring in the soil-plant-atmosphere continuum, the soil being viewed as a bio-physico-chemical reactor,

- the farming cultivation system, to test different alternative less polluting scenarios,

- the entire plain for evaluating the impact of agricultural practice changes on the groundwater quality time evolution as well as to test the willingness of consumers to financially contribute to set up such alternative programmes.