1. Former Ph.D. Candidate, Irstea, UR HHLY, Centre de Lyon-Villeurbanne, 5 rue de la Doua, BP 32108, 69616 Villeurbanne Cedex, France; presently, Postdoctoral Fellow, Dept. of Biosystems and Agricultural Engineering, Oklahoma State Univ., 120 Agricultural Hall, Stillwater, OK 74078 (corresponding author).
2. Researcher, Irstea, UR HHLY, Centre de Lyon-Villeurbanne, 5 rue de la Doua, 69626 Villeurbanne Cedex, France.
3. Researcher, CNR, 2 rue André Bonin, 69316 Lyon Cedex 04, France.