1. Agriculture and Agri-Food Canada; Soils and Crops Research and Development Centre; 2560 Hochelaga Blvd. Sainte-Foy QC Canada G1V 2J3
2. INRA; Unité Sol et Agronomie Rennes-Quimper; 65 Rue de Saint-Brieuc F35042 Rennes France
3. Agriculture and Agri-Food Canada; Dairy and Swine Research and Development Centre; P.O. Box 90, 2000, Road 108 East Lennoxville QC Canada J1M 1Z3