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Rice-fish benefits and problems

by John Sollows

In discussing a technology with potential new entrants, it is important to acquire it with potential benefits and risks so that they can make as balanced a decision as possible as to whether or not to try out the technology. If the potential new entrants are not aware of the possible benefits, they may miss a chance to improve their standard of living. Ignorance of the risks can also lead to serious problems and reduce the new entrants' self-reliance.

Problems and limitations

1 Rice-fish culture requires land. Landless farmers will have difficulties here unless they can make arrangements with the owner which must be mutually beneficial. Acquainting the owner with the benefits and problems associated with the technology will be important. The agreement should spell out what part of production goes to the farmer and what goes to the owner. Will rent be increased? Will it be rearranged? Will all additional benefits from fish catches go to the farmer?

Can rice-fish culture on communal land be arranged for landless farmers?

2. Production cannot be guaranteed especially in rainfed situations.

3. Pesticides and other toxic chemicals can kill fish and should be kept away from them. (See papers on site selection and on rice-fish culture, this volume.)

4. Transport of seed fish and stocking should be carried out correctly. Seed fish are very vulnerable at these stages; carelessness can kill. (See paper on stocking for rice-fish culture, this volume.)

5. Predators can seriously reduce fish stocks. Food nursing can solve this problem to a large extent. Submerged snake traps of wire mesh can be used to drown snakes. Snakes and frogs can also be caught manually. Frog eggs should be removed when discovered and dried. Birds can sometimes be scared away.

6. Thieves are perhaps the most difficult predator to deter. Living near the field helps sometimes. Partly filling the pond with bamboo or other branches makes netting the fish difficult and submerged barbed wire will probably ruin any net it snags. Obstacles (rocks or logs) placed on the dikes leading to the field makes access difficult at night. Watchdogs can also help.

Too much water

Too little water

7. Field preparation will demand a large investment of time, labour and money from the family. For poor farmers, labour availability often affects their ability to carry out the practice, limits the area they can prepare and affects the intensity with which the system can be managed. Old and young couples with small children will be particularly challenged here. As a rule of thumb, a 1 000 m2 field will not take more than ten 8-hour days to construct, if one person is doing the digging. A family with no time to feed the fish should stock lightly.

8. The farmer's managerial skills will increase in time. Many farmers succeed during first year, but many fail, as well. Failure among experienced farmers, however, is seldom

9. Rice yields are occasionally reduced by rice-fish culture. This occurs most often when large fingerlings are stocked before the rice is well-established. The water in some fields as well may be deeper than desirable for some rice varieties. Sometimes, rice will lodge and fish will graze on the rice seeds.

10.Some farmers complain that wild fish catches are reduced in fields with cultured fish. Tilapia is most often indicated as the suspect. These farmers feel that cultured fish in large numbers can scare away wild species.

11.Marketing problems can occur. A farmer can plan to keep his fish to sell when prices are high, but water shortage can force him to sell before this. Transporting fish to the market can also take time, especially when arrangements cannot be made beforehand. If a family plans to sell an important proportion of their catch: where, when and how will they sell it? Will this be easy?

12.Seed fish supply is a very common problem. A family may not always be able to get what it wants. Seed fish purchase usually occurs during the transplanting season when demands for fish are high and farmers have little time and money.

In villages where fish culture becomes widespread, the establishment of small hatcheries and nurseries deserves serious consideration. It is often advisable to encourage two or more interested villagers who feel that they are in a position to manage such operations to start the hatcheries, if the demand on the local market is sufficient. This will keep one producer from monopolizing the market.

Benefits and potentials

1. Compared to many technologies, rice-fish culture is a low-risk technology. It demands little money, is not particularly «new» or revolutionary for most rice farmers and involves few conflicts with other farm activities.

2. Fish cultured in ricefields provide farmers with a continuous, predictable, convenient supply of food. Farmers accustomed to depending on uncertain, declining stocks of wild fish appreciate this.

3. Rice-fish culture conserves water.

4. Rice-fish culture saves farmers time, allowing them to undertake income-generating activities or to improve on existing ones.

5. The small amounts of money needed mean that farmers need not take out loans. They, therefore, have many options as to how to use their fish: eat them, sell them, keep them alive (nature permitting), preserve them or give them away. The farmers do not have to make quick sales to reduce debts.

6. Income from sales can provide useful money at various times. Some farmers can sell brood fish or seed fish, as well as table fish.

7. Since this is a subsistence activity, to a large extent, there is little competition on the market among producers.

8. Rice yields are usually enhanced, although there is great variation from farm to farm. Yields are very rarely adversely affected when the farmer manages the system well.

9. The fact that this technology can modestly improve the lives of many poor rice farmers should make it of interest to development workers.

Issues for further consideration

One of the major constraints of the rice-fish system can be the submergence of the paddy fields due to seasonal floods, which leads to either loss of fish or a mixing of these with those from neighbours, which are then found in the ricefield once the flood pulse recedes.

Studies have shown that the existence of tilapias can increase the biomass of harvestable snakeheads in ponds. Changes in water flows and access to ricefields after modification of fish culture may be more of a problem.

The role of perennial water availability for continuous fish holding capability, i.e. a deeper sump or pond, may be considered. This may be valuable given marketing problems and for improving the availability of fish. Ponds allow more flexible marketing. While fish raised in ricefields may only be available for a short period, the option of storing them in a pond extends the fish availability season. Water conservation in rice-fish culture requires a deeper pond to be part of the rice-fish system.

In areas where per capita fish consumption is high, the cash saved from having to purchase fish can be a strong incentive to raise fish in ricefields. In irrigated areas, a high-input rice-fish system can improve subsequent crop yields and/or reduce nutrient requirements.

Economics of the system can vary. In northern Viet Nam, for example, income from the rice-fish system is often 1.5 to 1.7 times higher than from the rice-only system. While rice productivity in the rice-fish system is 10-17 percent higher compared with the rice-only system, the total rice production is often only 3-5 percent higher when considering the rice cultivation area lost to the trench. Another benefit of the system as experienced in northern Vietnam is the 50-65 percent reduced use of pesticides compared to the rice-only system.

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