ABSTRACT
Accelerated soil erosion is widely recognized as a severe problem in the tropics. A casual visitor to the tropics is usually amazed by the extent and severity of visible soil erosion on farmland by water, wind, and mass movement. Impact of soil erosion on productivity varies among soils, land use and farming systems, and ecoregional factors related to climate. Some endogenous factors that need to be addressed to improve soil quality and productivity in the tropics are subsistence agriculture, land clearing, and soil management. Traditionally farmers abandon the land when crop yields are too low because of either high incidence of pests or decline in soil quality. P. A. Sanchez et al. estimated tropical areas with soil-related constraints to crop production. For the tropical region as a whole, 64% of the land area is influenced by drought, 34% by steep gradient, and 2% by shallow topsoil.
