AGROFORESTRY SYSTEMS WITH POTENTIAL FOR ACID SOILS OF THE HUMID TROPICS OF LATIN-AMERICA AND THE CARIBBEAN

About 34% of Latin America is occupied by humid tropics which have a high proportion of acid soils (81%). The most widespread soil constraints in the region are aluminium toxicity (69%), phosphorus deficiency (50%), severe erosion hazard (17%), low nutrient reserves (72%), and poor drainage and flooding hazard (25%). Agroforestry research on acid soils of the humid tropics is very limited, and most statements about tree/soil relationships are still supported by only sparse or indirect evidence. The basic soil agroforestry hypothesis implies that appropriate agroforestry systems improve soil physical properties, maintain soil organic matter, and promote nutrient cycling. For well-drained acid soils of the humid tropics a successful agroforestry option should be adapted to the main soil constraints. Four options selected in this paper appear to be suitable for acid soils: tree plantations, fruit-tree-based production systems with intercropping, alley cropping and improved fallows. A low-input system is suggested during the establishment period of agroforestry systems, providing cash income and ground cover. © 1990.