Sunday, August 23, 2009

Fish Culture 2: Palay-isdaan (Rice-Fish Culture)

Abe V Rotor

This technology is indigenous. What we call palay-isdaan is an innovation of a traditional way of raising fish and other freshwater organisms while the rice plant is growing in the field during the rainy season.

Many wildlife species are found in ricefields as their natural habitat. These are commonly freshwater fish like hito, dalag, gurami, martiniko, and lately, since the fifties, tilapia. Then we have ulang (freshwater lobsters), shrimps, kuhol, suso’, and tulya. Strong rains release these organisms from their hibernation, usually in carabao wallows, ponds, and river basins – or in mud where they were ensconced during summer. The ricefields become one huge lake at the peak of the rainy season, and as the water subsides, these organisms are trapped in the paddies. Farmers pick them up for food, which is indeed a good source of protein for his family. Many find it a sport hunting them, while others find ways of protecting them until they reach maturity. The latter is the basis of palay-isdaan technology, which has these features.

1. The dike (pilapil) must be strong and high enough to prevent the fish to escape. To do this, trenches are dug around the rice field like a moat, two meter wide and one-half meter deep. The soil material is used to rebuild the dike.

2. Another model is to build a wide trench, 3 to 4 meters wide and one-half meter deep, running through the center of the rice paddy. This is usually done in low-lying areas where the water stays much longer. The trench serves as a natural trap for the fish as the surrounding water subsides.

3. A third model is recommended for irrigated areas where the rice field is managed like a fishpond. Here the farmer selects the fish he wants to grow, provides them with supplemental feeds, and gives attention more than what the other two models require. A commercial model would mean converting 30 percent of the total area into trenches.

Palay-isdaan is a revival of a virtually lost art and indigenous industry. Since the late fifties, the introduction pesticides and chemical fertilizers and their rampant use decimated wildlife in ricefields. As a rule therefore, unless the ricefields are free of these poisons, palay-isdaan will never succeed.

4. Because it takes time for the fish to grow to maturity it is advisable to plant traditional varieties which mature in 110 to 130 days. But this is feasible only where the rainy season is long and water supply is readily available. Traditional varieties generally do not need chemical spraying and fertilization.

Well-managed rice-fish farms in Central Luzon and other parts of the country can yield as much as 200 kg of tilapia per hectare. At P70 per kilo, the gross value is P14,000. While this gives 13 percent additional income, the farmer should consider a reduction in rice yield by at least 5 percent. Still palay-isdaan gives more income than rice monoculture.

Irrigated areas can have two fish crops a year, but this is not advisable because of the high cost of irrigation. Besides, it is virtually impossible to grow palagad rice (summer crop) without heavy dependence on chemical pesticides and fertilizers.


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