1. T.T. Cochrane, L.G. Sanchez, L.G. Azevedo, J.A. Porras, and C.L. Garver, 1985 . Land in Tropical America. A guide to climate, landscapes and soils for agronomists in Amazonia, the Andean Piedmont, Central Brazil and Orinoco . Centre Internacional de Agricultura Tropical (CIAT), Empresa Brasiliera de Pesquisa Agropecuaria (EMBRAPA), Centro de Pesquisa Agropecuaria dos Cerrados (CPAC), Cali, Colombia, pp.27 -41 .