RICE-FISH FARMING means growing rice and fish together at the same time on the same land. In rice-fish farming, farmers introduce another crop into the paddy field and that crop is small fish. This also includes growing fish and rice one after the other or growing side by side simultaneously in different compartments using the same water. This technique seems to be good for rice and fish. In this technique, the fish live in dense paddy fields and in turn, the fish provide fertilizer in the form of their excrement, eat the insect pest and circulate oxygen in a paddy field. The researcher tells that by keeping the fish in a paddy field, the yield of rice can be increased up to 10% and also additional supplies of fish.
The production of fish in the paddy field is as old as the practice of rice cultivation. The combined culture of fish and rice is also known as paddy-cum-fish culture. Rice-fish farming was introduced to Southeast Asia about 1500 years ago from India, where it is now most developed. At the end of the 19th century, rice-fish farming was practiced in Italy. Now it has spread to the United States and is well established in other rice producing countries like China, Japan and Taiwan.
Preparation for rice-fish culture
Rice paddies used for fish farming have different water properties than ponds and lakes. In the rice fields, the water depth is generally shallow. Due to this shallow depth, the temperature is also affected due to air temperature. During photosynthesis by other vegetative plants, oxygen is released in large quantities. Thus, the dissolved oxygen of the water is increased.
Usually, a paddy field with adequate water supply, better drainage facility, abundant sunlight and high water holding capacity is suitable for fish farming. In southern China, near lakes and rivers, there are deep-water paddy fields in low-lying areas. These low-lying fields are good bases for rice-fish cultivation.
Construction sheds and water structure
To maintain the proper water depth and prevent fish from escaping during heavy rains, the bunds should be raised up to 33.3 to 50 cm. There should be a hiding place for the fish during the shallow irrigation season, at high temperatures or during the application of fertilizers or insecticides. For this purpose, trenches or fish sumps are usually made after transplanting the nursery to facilitate the fish. In addition, sheds are built above the sump to protect the fish when the water temperature rises to 39°C. In some places there are no fish sumps and holes of 50-65 cm are dug deep in the side of the dyke. This hole serves as a wintering place in winter and a shed in summer. These holes are also better for fish that prefer dim light.
The most commonly used fish species are tilapia, carp (common carp, goldfish, European goldfish, mirror carp), catfish, trout, snakehead argus etc. However, viviparous and macro brachium are also suitable for paddy fields.
The fingerlings and fingerlings that are stocked in the rice paddies should be healthy, without damaging scales and sturdy with their body surface. The optimum stocking size for common carp is 10cm or more and for silver carp and bighead is 20cm or more. Catfish, mud carp, tilapia and fingerlings are stored after wintering.
Rice-fish culture management
For rice-fish farming, knowledge of rice farming and fish farming is necessary. In addition to this, the methods of drainage, filling, application of insecticides and fertilizers must also be understood.
Routine paddy management
In rice-fish farming, it is necessary to see the water structure for the right amount of water and to control the escape of fish from the structure. The optimum water depth of 16-17 cm should be maintained. Draining should be done gently so that fish can reach sumps or trenches. In addition, special attention should be paid to the change in water temperature, because when the temperature increases up to 40 ° C, it exceeds the tolerance of common carp. In such cases, the water should be changed with fresh water so that the temperature is lowered.
Rice-fish relationship and fertilization
He said the development and growth of rice and fish are greatly affected due to the amount, type and method of fertilizer application. Fertilizers like nitrogen, phosphorus, and potassium that are needed to grow rice are also natural fish nutrients. Thus, the production of fish feed is directly influenced due to the availability of fertilizers.
Predator prevention for rice-fish farming
There are many fish predators in the paddy field, such as animals, birds, snakes, Cybister, lactotrophs and frogs, etc. Prevention of predators is very important in the early stages because the rice is small and the field is fully exposed. Instead, the swimming motion of fish also makes them susceptible to predators. Again, during the harvest period when the water is low in the field, the fish expose themselves to predators. Thus, it is essential to control the loss through good predator control management. This predation can also be minimized by raising the water level so that rice growth is not affected.
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