1. 165 Boulevard Hébert, Université de Moncton—Campus d'EdmundstonEdmundstonNew BrunswickE3V 2S8Canada
2. Soil and Water Science Dep.2169 McCarty Hall, Univ. of Florida, P.O. Box 110290GainesvilleFL32611‐0290
3. School of Forest Resources and Conservation, Univ. of FloridaGainesvilleFL32611
4. Departamento do SolosUniversidade Federal de ViçosaViçosaMinas Gerais36570‐000Brazil