Rainfall is frequently erratic in semiarid areas of West Africa. Mean annual rainfall in Latin America ranges from 1400 mm in central Brazil to 4800 mm in Costa Rica. Dry spells frequently occur during the growing season in most of these areas, mainly in north and central Brazil. In South and Southeast Asia, more than half of the upland rice is grown in infertile soils. In most upland soils, P rather than N is the most common limiting nutrient.
Physiological disorders result from major and trace element imbalances.
Major toxicities are caused by high Al and Mg content in strongly acidic soils. The temperature of most regions of Asia, Latin America, and Africa is relatively favorable to upland rice except in some high-altitude areas in India, Indonesia, Myanmar, Nepal, and Thailand.