How to Raise Fish in Rice Paddies? A Detailed Explanation of the Benefits and Key Technical Points
Rice-fish farming is an agricultural breeding method that is mentioned quite often nowadays. Raising fish in the water surface of rice paddies not only yields fish products, but also uses the fish to eat pests and weeds in the paddy field, excrete manure, and churn the soil to promote fertilizer decomposition, creating favorable conditions for rice growth. It can generally increase rice yield by about 10 percent. So what exactly is rice-fish farming technology? What are the benefits of rice-fish farming?
I. Rice-fish farming technology
1. For rice-fish farming, the stocking varieties should preferably be herbivorous and omnivorous fish, such as grass carp, common carp, crucian carp, tilapia, etc. A few silver carp and bighead carp can be stocked, but bream is not suitable for stocking. In seedling beds for cultivating summer fry, 30,000 to 50,000 fry can be stocked per mu; for rice-fish co-cropping to cultivate fingerlings, 1,500 to 2,000 summer fry of 5 to 7 cm can be stocked per mu; for raising food fish, in double-cropping rice paddies with continuous rearing, stock per mu (summer fry): 300 common carp, 100 crucian carp, 100 grass carp, and 50 silver carp and bighead carp combined; with proper feeding, about 75 kg can be harvested per mu.
2. For rice-fish rotation with feeding, stock per mu 100 to 120 large-sized grass carp fingerlings, 150 to 200 common carp and crucian carp, 30 to 50 silver carp, and 10 to 20 bighead carp, which can yield 200 to 250 kg per mu. Stocking should be done early; for single-cropping rice-fish farming or continuous rice-fish rotation to raise food fish, stocking is generally done after the seedlings are transplanted and have turned green. For rice-fish rotation, water can be filled immediately after the rice harvest to raise fish, and the fish are caught before transplanting seedlings the following year.
3. For fertilizing rice-fish paddies, farmyard manure and base fertilizer should be the main types. When using chemical fertilizers, safe concentrations must be maintained, avoiding direct scattering into the fish ditches; alternatively, fertilizer can be applied alternately to half the field at a time. For pesticides, concentrations must be strictly controlled. Commonly used pesticides include dimethoate, methamidophos, trichlorfon, bisultap, and jinggangmycin. Highly toxic ones such as carbofuran, derris extract, sodium pentachlorophenate, toxaphene, and Bordeaux mixture should all be avoided.
4. Before applying pesticides, the fish ditches should be cleared and the water level deepened. Emulsion pesticides should be sprayed after the dew has dried, and powder pesticides should be sprayed while dew is still present, to reduce the amount of pesticide falling into the water. Pesticides can also be sprayed alternately on half the field at a time. If the fish show signs of distress, immediately irrigate with fresh water. When sun-drying the field, make sure to dry the field without drying out the fish. Patrol the field frequently to check the growth of rice and fish and whether the field ridges and fish-blocking screens are secure. Pay attention to drought prevention and escape prevention. Feeding should be done at fixed times, in fixed amounts, at fixed locations, and with consistent quality.
II. What are the benefits of rice-fish farming?
First, rice-fish farming can promote increased rice yield. Rice-fish farming is a form of intensive expanded reproduction, a reuse of national land resources, and it can produce aquatic products without occupying additional farmland. Experience from various places shows that developing rice-fish farming not only does not affect rice yield, but also promotes increased rice yield. Rice paddies with fish generally can increase rice yield by 5—10%, with higher increases of 14-24%.
Second, rice-fish farming can increase the supply of aquatic products to society and enrich people's “vegetable basket.” In recent years in Jiangsu, Sichuan, Guizhou and other places, rice-fish farming has become one of the main local aquaculture methods. Rice-fish farming can achieve balanced market supply and has played an important role in stabilizing aquatic product supply, stabilizing market prices, meeting “vegetable basket” needs, and improving people's dietary structure. Especially in some areas lacking water resources and with poor transportation, developing rice-fish farming, producing locally and selling locally, has effectively solved the long-standing problem of “difficulty in eating fish” in these areas.
Third, rice-fish farming can significantly increase farmers' income. Rice-fish farming increases both grain and fish, and can also reduce the use of chemical fertilizers and pesticides in rice paddies, saving labor, increasing income and reducing expenditure. Generally, fish-farming rice paddies can increase farmers' income by 220 yuan per mu. Implementing high-standard rice-fish engineering for rice-fish farming can increase income by 350 yuan per mu. Using rice paddies to raise famous, special and high-quality aquatic products and conducting rice-fish-mushroom ternary composite farming can increase income by more than a thousand yuan per mu of rice paddy.
Fourth, rice-fish farming promotes the optimization of the ecological environment and enhances the ability to withstand natural disasters. Because of rice-fish farming, field ridges are correspondingly heightened and reinforced, and ditches and pits are dug, greatly increasing water storage capacity, which is conducive to flood control and drought resistance. In some hilly areas, implementing rice-fish engineering can increase water storage by 200 cubic meters per mu of rice paddy, greatly enhancing drought resistance. For some water-scarce areas with more frequent droughts, fish-farming rice paddies, due to their large water storage capacity, can effectively delay the effects of drought. The environmental improvement effect of rice-fish farming is mainly shown in its good insect-killing effect. According to tests, the density of mosquito larvae in fish-farming rice paddies is 80% lower than in paddies without fish, mainly because the fish raised in rice paddies consume large numbers of mosquito larvae and snails, which can reduce the incidence of serious diseases such as malaria, filariasis and schistosomiasis.