mid tropics restricts the types of crops and animals that can be raised and favors the spread of pests and diseases. The heat and humidity can also affect farmers and others involved in the production process, in that the hottest and wettest weather often coincides with the difficult tasks of land preparation and planting (Juo, 1989). Finally, climatic conditions in the humid tropics also result in high postharvest losses to pests and spoilage, and pose special problems for storage, transportation, and processing.

The soils of the humid tropics vary from region to region (Table 1-6) and have special requirements, limitations, and possibilities for agricultural use. They are subject to several constraints, including low nutrient reserves, aluminum toxicity, high phosphorus fixation, high acidity, and susceptibility to erosion. These constraints, and the methods that have evolved to overcome them, vary among soil types and from region to region. Ideally, the soil, along with considerations of topography and water availability, should determine the