Fish culture in the rice-field
Our country is fertile with all sorts of natural resources. Now the country has undergone a great deal of progress. Natural sources of water such as rivers, canals and ponds which used to be the habitat of fish have changed. Irrigation system such as in the construction of dikes and dams for storing water for agricultural usage has given rise to an impact on the natural breeding place of fish. This can be seen at places such as Maharat Swamp in Ayutthaya; Kamyad Swamp, Chainat; or at Dan Chang, Suphan Buri.
Fish is a main ingredient of meat dish eaten daily with rice. It has very high nutritional value, is easily digestible, full of amino acid essential to physical growth.
Fish culture in the rice-field is not an innovative idea. It has been implemented in our country since 1948. Recently, it has become a popular venture once more. In Japan, Taiwan and Indonesia, fish culture in rice-fields have long produced good results.
Normally during the rice-planting season, when rain water floods the rice-field, fish from natural water sources such as rivers and canals will swim out of their usual habitat to inhabit and grow up in the rice-field. If farmers adapt their rice-field to make it a living and breeding area for fish, certainly they will gain good result and get more fish from their field.
What needs to be done is to choose the appropriate rice-field and improve it a little to make it suitable for fish culture. This will bring about more food and more income for the family, using the same old space of the field. This method will help to augment water animals for the requirement in the country.
Natural food such as tiny plants and living animals already exists in the rice-field. Some of these are visible and some are not. In ordinary circumstances, such supply of natural food has not been made use of. If fish is raised in the rice-field, such food can be consumed. Fish raised there will also help eliminate weed. Other enemies of rice such as worms and caterpillar living in water can be the best food for the fish. The swimming action of the fish with its tail fanning and moving around among the rice plants will help stirring and shifting ground soil for the rice-field, conducive to the better-than-usual growth of rice. Fish droppings consisting of valuable nitrogen will also serve as fertilizer to the rice plants.
However, not every rice-field is suitable to be made into fish culture ground. If the field can hold about 30 centimetres of water higher than the usual level throughout the rice planting season and that level can be maintained, not higher and not lower than that, the outcome of fish culture there will be very good. The characteristics of the rice-field suitable for fish culture should be:
1. Close to sources of water such as streams, ponds, pools, canals, feeder waterways where water can be drawn into the field. The field that depends solely on rain as source of water should be able to retain water for more than 90 days.
2. It must not be too low or swampy and not susceptible to flood.
3. Easy to maintain.
4. A field of more than 5 rai in land area will be suitable and the venture will be worth the effort. Fish pond area can be any shape and size. Preparation should be made prior to soil adjustment and ploughing. The small dikes of earth surrounding the field should be made higher by about 3 kueb (Approximately 20 inches) for the field with the normal depth of 1 sok (about 40 inches) of water during the whole rice planting season. The field with a fish-inducing pond already in existence on it should have the earthen dikes reinforced. The fish-inducing pond should be dug at the deepest part of the field to cause fish to assemble there when the water level has been reduced. This pond should serve as a nursery of small fingerlings for as long enough as they attain the size of 5-10 centimetres. This size is suitable for fish before it is let out to be on their own in the vast field. Fish should be nursed in the nursery pond for about a month before the rice-planting season.
Fish to be cultured should belong to the easy-to-care-for and rapidly-growing breed. They should be strong and sturdy. Their fingerlings are easily obtainable. They must not be destructive to the rice plants. Their meat should be tasty and favoured by the villagers in the area. Such fish may be: pla nai, white carp, nuan chan thet, pla huato or plasong. These types of fish eat natural food belonging to the plant and small animals family in the rice-fields so they can grow quite fast.
The number of fish to be kept in one plot of land should not be too many or too few. In a 1-rai piece of land, about 400-800 fish should be cultured there depending on the size of fish. If several breeds of fish are raised together, such as pla nai with carps, they should be kept at a ratio of 4-2; in other instances, 500 carps at the size of 3-5 centimetres can be raised together with 30-50 pla chine or Chinese carp in an area of 1 rai of land. After 6 months, they will grow to the size required by the market. If there is plenty of water in the field, about 10-20 pla hua to (big-headed fish) or pla nuan chan thet can be added per a rai. During the first or second week after the fish was released into the field, supplementary food such as finely ground rice husks should be given at the place where the fingerlings swim. After that all the fish can be left to live together. If a plant disease occurs among the rice plant necessitating the use of insecticide, fish should be scooped out of the field before the insecticide is applied; otherwise fish may perish.
Fish culture in the rice-field is an occupation that farmers can undertake all year round. After the harvest, the field can again be used to raise fish if there is abundant water at the 1st and the 2nd periods of the process of the culture.
Fish culture in the rice-field can help solve the problem of the lack of food among farmers. At least it can bring about a decent livelihood. It can also bring in supplementary income for farmers. Rice fields which formerly produced only a small amount of fish may be able to bring in at least 20 kilogrammes more of fish per rai or higher. All over Thailand, there are about 43 million rai of rice fields. If only one in a hundred of this acreage is earmarked as appropriate for fish culture, thousands of tons of fish will turn out as added product. It is now suitable for our farmers to adapt their rice fields to make them more useful to the family and to bring better economy to the country.
Written By : “Pak Pao Sam”
Translated by Sudchit Bhinyoying