Upland rice is a type of rice grown on dry soil rather than flooded rice paddies. It is sometimes also called dry rice.
Introduction
Today nearly 100 million people depend on upland rice as their daily staple food. Almost two-thirds of the upland rice area is in Asia, with Bangladesh, Cambodia, China, Northeastern India, Indonesia, Myanmar, Nepal, Thailand and Vietnam being important producers.
Upland rice is grown in rainfed fields prepared and seeded when dry, much like wheat or maize. Ecosystems involving upland rice are often relatively 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 mm 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.
Many upland farmers plant local rice that does not respond well to improved management practices, such as intensive farming using artificial fertilizers—yet they are well adapted to their environments and produce grains that meet local needs.
Although the rice technology of the 1960s and 70s focused on irrigated rice, research also studied the cultivation of upland rice. Researchers produced cultivars adapted to poor soils and with improved pest resistance and drought tolerance. Some have outyielded traditional rice by more than 100 percent in evaluations. Scientists at national agricultural research systems have crossed these improved strains with local cultivars, introducing hybrid varieties of rice.
Challenges to upland rice farming
New challenges are emerging in the world's upland rice farming areas, where poverty is already a problem. These farmers try to make a living from farming on deficient soil and that makes it hard to grow their crops.
Population growth, the demands of urbanism and industry, and the increasing adoption of high-value cash crop farming in the surrounding lowlands are leading to strong competition for upland terrain.
The uplands have traditionally suffered from drought, infertile soils, weeds, and plant diseases. Soils there have been severely eroded and degraded as a result of the slash-and-burn agriculture that for many years followed logging. 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. In addition to the usual upland problems, those involved find themselves facing an urgent need to conserve soil and the diversity of plant species and to cope with increasingly frequent and severe weed and disease infestations.
Blast fungus
Recently, scientists have been improving their knowledge of the genetics of resistance to the blast fungus, one of the most damaging diseases of rice. Using the techniques of biotechnology, they are developing cultivars with more durable disease resistance.
In the uplands, the blast is particularly important because the environment favors its proliferation. Although many traditional upland cultivars show stable resistance to this disease under low-input cropping practices, they have other characteristics that make them difficult to use in intensified systems. So, the risk from blast increases as cropping practices intensify and improved varieties are introduced.
Scientists from the International Rice Research Institute (IRRI) have been working with colleagues in the Upland Rice Research Consortium to better understand pathogen populations and to identify resistance genes found in some cultivars. Armed with this knowledge, they are working with IRRI's upland rice breeder to combine such genes with other desirable traits for incorporation into new upland varieties.
Consortium scientists are also trying to understand how upland rice farmers' cropping systems contribute to soil erosion, with the aim of proposing possible erosion control techniques. Studies in the Philippines have shown that hedgerows of trees, shrubs, and grasses along hill contours can help reduce soil erosion by up to 90 percent. Rice or other crops are planted between these strips of permanent ground cover.
Leguminous plants in hedgerows make substantial amounts of atmospheric nitrogen available to both rice plants and annual crops and recycle other nutrients and organic matter.
Such legumes can simultaneously increase farmers' incomes and contribute to the sustainability of the farming system.