Tropical soils: An Asset to world Development

摘要

Soils vary greatly in both temperate and tropical regions. The stereotype dark drown, highly fertile temperate region soils (Mollisols, Alfisols) and the stereotype acid, red, low fertility tropical soils (Oxisols and Ultisols) represent a minority inboth regions (Table 1). Soils are now classified according to quantitative soil taxonomy, akin in precision and complexity to plant taxonomy (Soil Survey Staff, 1999). The tropics include all 12 soil orders; 38 out of the 53 suborders; hundreds of greatsoil groups and thousands of soil families and soil series (Sanchez and Palm, forthcoming). The only property common to all tropical soils is the lack of seasonal soil temperature variation greater than 5°C (Buol et al, 1997) All other generalizationsare essentially incorrect. To state that all tropical soils are old and infertile is equivalent to stating that all temperate soils are young and fertile.