Evaluation and revision proposal of the second Action Programme in Walloon Region (Belgium). In accordance with the Nitrates Directive, the second "Durable Nitrogen Management Plan" (PGDA) will be reviewed in 2010. In the light of scientist experiment's results exposed at the workshop "Nitrate-Eau" held in Peyresq (2 to 5 June 2009), modifications of the second programme are recommanded. These deal with organic and mineral nitrogen fertilisation for crops and meadows, catch crops, soil nitrogen residue controle at the beginning of the nitrate leaching period, meadow's ploughing management and the dairy cow's standard for nitrogen production.