An integrated rice - fish system [Lao People's Democratic Republic]

Good Practices

An integrated rice - fish system [Lao People's Democratic Republic]

Definition of the Technology:

Raising fish in rice paddy to optimize the use of land.

Description:

A rice-fish system is effectively the integration of a rice field and a fish pond. This idea was initiated by local people who have been living with natural resources including forests, mountains and streams for generations. Their idea was to optimize these resources – namely the land and water to fish raising in the rice field at the same time. In the past, people were dependent on shifting cultivation. However, they recently switched to lowland rice cultivation because shifting cultivation for upland rice cultivation is insufficient for household consumption and against government policy for natural environment conservation; whatever the farmer still keep the upland rice cultivation in burned area but no allow to expand the new area. Raising fish in a rice paddy is an important technique to encourage permanent land use. It should be initiated in an appropriate environment especially one where there is water supply throughout the year. The rice paddy should be located along a stream, a river or an irrigation canal so that the water can be adequately channeled both in and out of the field. Ta-Oy is a district where there is limited productive agricultural land with most of the rice paddies being situated along mountain valleys and at the base of the hills. In this area agricultural activities rely entirely on natural rainfall. The creation of rice fields requires a considerable amount of labour from local households or otherwise a tractor needs to be hired to clear the area along the mountain valleys. Basically, rice paddy development in such areas requires the construction of small dykes in cross sections of the stream channel. Ground levelling may be required to ensure that the water reaches all of the plots. Typically, these paddy fields are arranged in a terraced formation. Raising fish in rice fields may require different methods from those of traditional rice paddies as there need to be appropriate measures taken in order to prevent natural disasters, particularly soil erosion. Rice fields that are suitable for fish raising need to have higher levees built around them and be equipped with an appropriate drainage system. The farmer also needs to construct deep retention water in the pond next to the rice field so as to regulate the water from the canal flow directly to rice field, which helps to reduce levees erosion. The integrated rice-fish system sets out to maximize land use as it enables both rice production and the raising of fish thereby providing increased food security for households as well as improving their income. In order to apply the technology, farmers need drainage pipes which are installed on levees to leveling the water in rice fields that are a part of the irrigation system. Other production inputs include the rice variety, fish fingerlings, knifes, hoes, spades, shovels and sickles. Both of these activities are mutually beneficial because the food waste and suspended nutrients in the water resulting from the fish waste provide a natural fertilizer for the rice and this also enhances the soil’s fertility, whilst at the same time the rice stalks provide a habitat for the fish. When pests or insects threaten the rice crop, fish fulfill the role of consuming them. The practice of raising fish in rice paddies also helps to reduce water pollution due to the process of eutrophication through fertilization, even though process of decaying is loss of oxygen production but it can be regenerated by phytoplankton’s photosynthesis and water sources recharge . In fact, the technology reduces expenses and labour required for the cultivation of rice and at the same time preserves the environment, as the soil is moist throughout the year. This technology is very pragmatic for farmers as it allows them to provide sufficient rice and fish for their families’ needs. Benefits also include increased productivity in comparison to shifting cultivation which provided insufficient outputs and farmers often experienced rice shortages. Farmers can now cultivate rice for two seasons. Another benefit are the nutrients and the decay from fish faeces which become a natural fertilizer for the rice and add microorganisms to the soil. An integrated rice-fish system can be implemented in an area of 500 sqm (25m x 20m), with a water depth of 0.5 – 1 m and a gradient between 3 - 5% which is similar to that of terraced rice paddies. The space between rows of rice stems should be 20 – 25cm with an open area for the fish without any rice plants approximately 5 square meters from the levee to the field where there is a water pipe to generate oxygen for fishes. The fish population should be at a density of five fish per square meter, and suitable species include Pa pak (Barbonymus gonionotus), tilapia and Pa kheng (Anabas testudineus).Strengths: (1) An increase in rice production in a smaller area because the farmer is able to cultivate rice for two seasons as well as in fish production (both a dry season and a rain fed rice crop). (2) An integrated fish culture maximizes the agricultural land. (3) Nutrients and fish faeces are essential for rice as well as add microorganisms to the soil. (4) Raising fish in a rice field provides a good return and optimizes land use. Weaknesses (1) A lack of funds to implement this technology – farmers need some source of funding. (2) It has been implemented traditionally without any technical knowledge –there is the need for farmers to receive technical advice regarding the maintenance of a rice-fish system as well as land management. (3) The need for appropriate equipment to implement the production process. (4) If the fish population density is too high, it might affect the health of the rice. (5) It is not possible to propagate an adequate number of fish fingerlings for the next year in the existing rice-fish system, an individual nursery pond for propagation is required.