Sawah Tambak rice-fish system in Indonesia

Literally, sawah tambak means ricefield pond (bracitishwater). However, this term refers here to the 12,152 ha rice-fish farm area in East Java which involves 15,000 households. Depending on the depth of floodwater in each area and fish or rice culture intensity, the sawah tambak rice-fish systems can be classified into the following:

System in Indonesia

1. Concurrent rice-fish system during wet season: appropriate in areas where inundation and the risk against submergence of rice is low. On the other hand, water is not sufficient to support a dry season rice crop.

2. Concurrent rice-fish (wet season) followed by dry season rice: done in areas where standing water is not so deep and water is sufficient to support dry season rice crop.

3. Fish culture (no rice) in wet season followed by dry season rice: appropriate in areas where flooding is deep.

4. Fish culture throughout: done in areas where farmers prefer to raise fish instead of rice in the entire flooding season.

OPERATION OF THE SAWAH TAMBAK SYSTEM

Field Components

1. Peripheral dike. This is built by excavating the inner peripheral canal of the field. base width: 4-5 m; top width: 2-2.2 m; height: 1.4 - 1.8 m

2. Peripheral canal/trench. This serves as a fish refuge, nursery, holding/transition place, catching canal, and source of water for dry season rice. bottom width: 2 - 4 m; top width: 2.8 - 3.2 m; depth: 0.3 - 0.7 m

3. Ricefield area. The area used for planting rice is surrounded by a temporary bund 0.5 m high. This retains the water required by rice for its growth. The bund is also needed especially in concurrent ricefish '' system. sketch of A typical SAWAN tambak sketch OF holding place

Sketch a typical sawah tambak

Sketch a typical sawah tambak (transection)

Water Supply

Water comes from rainfall or seepage. Thus, there is no need to provide water inlet or outlet gates. When it is necessary to reduce or add water, pumping or boiling out water by the traditional method is used.

Prevention of Fish Escape During Floods

Farmers have ready grasses, plant leaves and similar materials to spread on top of dikes when flooks overtop dikes.

Preparation of Ricefield Area

The ricefield enclosed by the dikes is prepared just like an ordinary ricefield. Land preparation begins in September just before the onset of the rainy season, either by dry or wet method.

Nursery/Holding and Transition Area

These are constructed in the peripheral canal. The nursery is 10 m long, 5 m wide and 0.75 m deep. Water filling from outside is done through pumping or by traditional method. Fry stocking is done 2-3 days after water filling.

Oftentimes, prior to stocking fish in the entire sawah tambak, the milkfish and tawes fry are cultured separately in nursery/holding corner in the peripheral canal. The milkfish (stocking rate: 500/sq m) are raised here up to 45-60 days. The tawes (220/sq m) are kept at the holding place (with about 50 cm water depth) for one month before releasing them into the field.

Fertilization

Organic (compost, animal manure, green aquatic plants, etc.) and inorganic (urea and trisuperphosphate) fertilizers are applied The application rates are:

Urea is applied at the rate of 100-150 kg/ha/yr. and trisuperphosphate is 300-450 kg/ha/yr.

The total amount of urea and trisupemhosphate is each divided into three equal parts and applied thrice. As an example, the first application is a mixture of 25-50 kg/ha urea and 100-150 kg/ha trisuperphosphate.

Cultural Management and Harvesting

Combination of milk fish (Chanos chanos) and tawes or silver barb (Puntius gonlonotus) are stocked. Common carp is also added if available Stocking sizes and rate are as follows:

Culture period is 4-7 months, depending on the available standing water. In areas with deep water, culture period extends to one year. Stocking of fish can be done more than once. Harvesting is done twice or thrice. With no feeding, yield is about 2,000 - 3,500 kg/ha.

PALAWIJA IKAN SYSTEM

Immediately after the harvest of the dry season rice crop, dikes are raised by using a hoe, to contain water depth of 30-40 cm. The stocking size and rate vary. in West Java, common carp of size 3-5 or 5-8 cm are stocked at 5,000/ha without feeding. In North Sumatra, consumption size is produced in palawija system. The usual sizes stocked are 30-50 9 or 50-100 9 at the rate of 1,000-1,500 (no feeding); and 1,5003,000 (with supplemental feeding). Supplemental feeds are rice bran, chopped cassava, corn kernel soaked in water, poultry feed, kitchen refuse and others. Harvesting the fish is done by draining the field

Palawija ikan system

CROPPING PATTERNS

The above systems are combined into sequential cropping patterns in a year such as: