1. Researcher, UMR G-EAU, Cemagref, 361 rue J-F Breton, 34196 Montpellier Cedex 5, France (corresponding author).
2. Research Engineer, UMR G-EAU, Cemagref, 361 rue J-F Breton, 34196 Montpellier Cedex 5, France.
3. Assistant Professor, UMR G-EAU, SupAgro/IRD, 361 rue J-F Breton, 34196 Montpellier Cedex 5, France.
4. Researcher, UMR G-EAU, Cemagref, 361 rue J-F Breton, 34196 Montpellier Cedex 5, France.