Upland rice
Almost two-thirds of the upland rice cultivation occurs in Asia, with Bangladesh, Cambodia, China, Northeastern India, Indonesia, Myanmar, Nepal, Thailand, and Vietnam all being important producers.
Scientists at national agricultural research systems have crossed these improved strains with local cultivars, introducing hybrid varieties of rice.
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.
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.
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.
Such legumes can simultaneously increase farmers' incomes and contribute to the sustainability of the farming system.Weeds are the most serious biological constraint to upland rice production.
The goals are to understand the diversity of farmers' practices and decision-making processes and to grade the factors that limit rice crop yields.
In one project on phosphorus management, they are investigating how weed communities change as soil fertility is improved over time in the Philippines, Indonesia, and Thailand.
By planting this cultivar and enhancing their competitive ability through good management practices, farmers should be able to reduce the amount of hand weeding necessary while achieving maximum yields.
Rotations of rice and legumes could lead to stable, higher-value production if phosphorus is added and that soil quality does not degrade over time.
The acidity present in the subsoil of many upland areas prevents plant roots from reaching the moisture and nutrients therein, thus reducing crop yield.
French collaborators from l'Institut francais de recherche scientifique pour le développement en cooperation are planning similar experiments in Thailand and Vietnam.
A perennial variety of rice that would not need to be replanted annually could help reduce erosion by providing a permanent ground cover and deeper, tighter root systems.
[7] The challenge facing scientists is to produce a high-yielding perennial plant adapted to the poor soils of the uplands, with high yields from low-purchased inputs, and resistant to diseases and insects.
