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CORIFA |
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INTRODUCTION
CORIFA or Country Rice Facts. Rice is grown on a wide range of ecological environments (from dry land to flooded land, even under several meters deep); varying altitudes (from sea level to about 3,000 m above sea level); varying climates (from tropical to temperate); and different soil types and associations (from saline soils along sea-coasts to Aluminium toxic upland). In 1997, rice is cultivated in 110 countries in five continents. Although the literatures on rice plant, rice production and technologies, and related factors are rich, it is often quite difficult and time consuming for interested individuals and/or agencies to obtain a comprehensive picture of the situation of rice production and development in the country of their interest. The main objective of the development and publication CORIFA is to provide such summary picture of rice production factors and situation in each of the rice producing countries. It is our hope that the present publication of CORIFA will promote the interest and support to sustainable rice development worldwide. Also, we should be grateful to receive your comments and contributions aimed at improving the CORIFA. You could be an active partner of the maintenance and improvement of CORIFA by acting as focal point for collection and provision of information on rice production, rice technologies, and related factors in your country and/or region, whichever is applicable. If interested, kindly send your full name, title, and complete address including Email, telephone and fax numbers to Nguu.Nguyen@fao.org |
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BASIC STATISTICS With the exception of the information on harvested areas under different ecologies (e.g. Irrigated, Rainfed Lowland, etc..), detailed statistical data under this section could be obtained from FAOSTAT at:
RICE ECOLOGIES Several attempts have been made to classify the ecologies or environments in which rice is grown, and relate them to the different terminologies to describe rice production systems. The following classification of rice ecologies into irrigated, rainfed lowland, upland and others (IRRI, 1984) is used in CORIFA. 1. Irrigated Ecology (IRR): In irrigated ecology, rice plants are supplied with adequate water throughout the growing season. In many irrigated rice areas, rainfall supplement irrigation water. The landscape position of most alluvial river terraces means that they are not normally flooded except when the river is at its peak. By diversion of river water they can, however, be flooded by leading water through canals and ditches to the points of entry to rice paddies. The paddy fields are bunded and arranged so that water may flow under gravity from higher to lower fields. They are, of course, dependent on water being available from the stream or river. This limits the use of many such systems to the monsoon period, and also means that some are subject to periodic drought. They may be described as diversion irrigated. A water storage irrigation system (including dams and reservoirs) not only removes the uncertainty of yields being limited by drought but also enables a crop to be grown during the dry season, when radiation is mot intense and insect and disease pressure least. Groundwater, if of good quality, may also be used for irrigation using pump systems - "Groundwater" or "pump irrigated". 2. Rainfed Lowland Ecology (RFL): In rainfed lowland ecology, water supply to rice plants is principally provided by rainfall, run-off water, and under-ground water. The rainfed lowland rice fields are usually bunded. The bunds serve to retain floodwaters, as well as rainwater which falls during the growing season. Rice fields, in general, are submerged or flooded with water depths varying from 0 to 100 cm for considerable period or periods during croping season. Rainfed lowland rice crops may suffer from both drought and flood. At higher terraces, rainfed lowland ecology may be drought prone. In the backswamps, rice crops usually suffer from strongly reduced soil conditions due to poor drainage. Most of inland swamp rice in Africa (e.g. bas-fonds, dambo, fadama, etc...) are rainfed lowland rice areas. In Sub-Saharan Africa, rice is also planted to hydromorphic soils. Rice planted to hydromorphic soils at lower slopes of an undulating landscape where the water table moves to the surface for substantial period during cropping season is classified as rainfed lowland rice. Also, the lowland rice irrigated with water which is diverted from the streams at the upper part of a drainage system is also classified as rainfed lowland rice as the quantity of irrigated water is usually not substantial. 3. Upland Ecology (UPL): In upland ecology, rice is grown in areas where there is no effort made to impound water and where there is no natural flooding of the land. Rice planted in areas at higher slopes of an undulating landscape where the ground water table is at 50cm below the surface or deeper are upland rice, although the soils may be classified as hydromorphic as in West Africa. A significant part of the upland rice is grown by people who practices shifting cultivation. In shifting cultivation, rice is usually inter-cropped with maize, cassava and other crops. 4. Other Ecologies: At the low-lying lands of the deltas of large rivers such as the Mekong in Vietnam and Cambodia, the Chao Phraya in Thailand and the Ganges-Brahmaputra in Bangladesh, deepwater and "floating" rice are still grown. In spite of the major efforts which have been made to control the flow of these rivers, the areas behind the river leeves are often flooded to depths, which is sometime of several metres. The ecology of rice at these areas is Deepwater or flood-prone ecology (DPW). Rice is usually seeded immediately before the arrival of the flood waters, and little more is done until the time arrives for the crop to be harvested. In some areas, the rice may be transplanted once or twice as the floodwaters advance, in an attempt to save the young rice seedlings from drowning if the floods rise too rapidly for the seedlings to survive. The varieties adapted to the deeply flooded areas are sometimes referred to as floating rice. The plant of floating rice elongates with increasing water depth but retains a rooted foot hold in the soil. Floating rice varieties also form adventitious roots from the nodes which are able to absorb nutrients directly from the floodwater. Rice is also planted in Tidal Wetland (TDL) in the coastal plains of Southeast Asia and West Africa, where soils are flooded due to the influence of the ocean tides and/or the discharge of rivers into the ocean during periods of high discharge. In West Africa, this rice is called Mangrove rice (TDL). Salinity, the presence of peat in many of the swamps, and the occurrence of acid sulphate soils, introduce special problems for rice cultivation and its sustainability in these areas.
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