This, in turn, destroys the watershed, producing problems in the lands below. Already the new upward pressures are resulting in a movement toward permanent agriculture and intensification of land use in upland areas. Nearly 100 million people now depend on upland rice as their daily staple food. Almost two-thirds of the upland rice area is in Asia. Bangladesh, Cambodia, China, India, Indonesia, Myanmar, Thailand, and Vietnam are important producers.
Upland rice is grown in rainfed fields prepared and seeded when dry, much like wheat or maize.
The ecosystem is extremely diverse, including fields that are level, gently rolling or steep, at altitudes up to 2,000 meters and with rainfall ranging from 1,000 to 4,500 millimeters annually. Soils range from highly fertile to highly weathered, infertile and acidic, but only 15 percent of total upland rice grows where soils are fertile and the growing season is long. Although the rice technology of the 1960s and 70s focused on irrigated rice, farmers in the uplands were not forgotten. Researchers produced cultivars adapted to poor soils, and with improved blast resistance and drought tolerance. Some have outyielded traditional rices by more than 100 percent in evaluations.