1. Département des Sols et Génie Agroalimentaire, Centre de Recherche en Horticulture; Université Laval; Sainte-Foy Québec Canada G1K 7P4
2. Land Resource Science Department; University of Guelph; Guelph Ontario Canada N1G 2W1
3. Mid Florida Research and Education Center, IFAS; University of Florida; Apopka FL 32703
4. Hortau inc; 840 Ste-Thérèse, Suite 300 Québec Canada G1N 1S7