Denitrification in the upper vadose zone layers: a comparison between a fluvic hypercalcaric cambisol and a haplic calcisol Patrice Cannavo, Agnès Richaume, Pierre Renault, Christophe Emblanch, Patrick Bertuzzi and François Lafolie Agronomie, 22 5 (2002) 479-488 DOI: 10.1051/agro:2002025