Production of fish in rice fields is almost as primitive as the practice of rice culture itself. Rice farming with- fish culture is a type of duo culture farming system in which rice is the sole enterprise and fishes are taken to initiate additional for extra income. Rice-cum fish culture is practiced in many rice-growing belts of the world including China, Bangladesh, Malaysia, Korea, Indonesia, Philippines, Thailand and India. Rearing of fish along with paddy is an older farming practice adopted in India. It has largely been practiced in a traditional primitive way in the coastal areas of the country.
Rice and fish are the staple food of India whereas India is an agro- based developed country. The future development of the country is very much related with the agricultural sector. As an socio-economic activity fisheries ranks second in the world to agriculture sector. Fishery as on the major sub-sectors has been playing a significant vital role in terms of nutrition, employment, foreign exchange earnings, good supply and more importantly socio-economic stability in the rural areas. India is the land of water with several rivers and the country is very rich in natural water resources in the form of rivers, reservoirs, ditches, lakes, ponds, flood plains and large areas of rice fields etc. The Rice--fish farming culture involves the simultaneous production of rice and fish in irrigated rice fields so as to obtain an added production of fish with rice.
The main objective of this sustainable farming practice is :
i. To assess the relative profitability of using rice-cum-fish culture compare to rice monoculture.
ii. To determine the effects of the rice-cum-fish culture in changing yields, total costs, fish consumption and labour employment as compared to the monoculture.
iii. To identify the major problems in conducting integrated rice-fish farming and
iv. To determine the effect of different fish combinations on fish yield in Rice-cum-fish culture system, with a view to recommending the outcome to prospective rice/ fish farmers.
Benefits of Integrated Farming/ or rice cum fish culture system:
1. Improves the soil fertility & soil health.
2. Increasing economic yield per unit area.
3. Reduction in production costs.
4. Decreases farm input requirements.
5. Multiple income sources.
6. Family income support.
7. Efficient utilization of family labour.
8.Reduction in animal feeding requirements.
9. Minimize the use of chemical fertilizers
10. Provides balanced nutritious food for the farmers.
11. Solves the energy problems with biogas.
12. Avoids degradation of forests.
13. Enhance employment generation.
14. Pollution free environment.
15. Recycling of resources.
16. Improves the status & livelihood of the farmer.
Practices / or technology engaged in rice cum fish farming
The site selection for rice cum fish farming is low lying area where water flows easily and available at any time in needs.
The soil of the paddy field should be fertile rich in organic manure and has high water holding capacity. Usually medium textured soils like silty clay or silty clay loam are most suitable for paddy cum fish farming/ or shrimp culture.
The plots selected for paddy cum fish culture are normally prepared in the month of February by raising their embankment all along the plots. The paddy fields are suitable for fish culture at the areas because of strong bund, which prevent leakage of water to retain water upto desired depth and also guarded the escape of cultivated fingerlings/ or fishes during the floods. The dykes should be built strong enough to make up the height due to geographical and topographic location of the field. The bamboo screen mating should be done at the base of the bund area for its support.
After the completion of bund construction the base of paddy fields are leveled with the help of spade and local made wooden plates. Manual weeding is done during the month of February followed by construction of irrigated channel for easy passage, storage and draining of water. There are 2-3 channels constructed at the middle of paddy field for water management. That channel divides the paddy field perpendicular and horizontally bisect at a point. It is important to note that almost all paddy field have one or two inlets and more outlets. The former serve as entry of water required for the field and the later as outlets, one which remains at the bottom side of the dykes is meant for draining out the water for harvesting paddy crops and fishes. The remaining outlet constructed at the middle height of the dykes is meant for maintaining desirable water depth. Once the dressing work is over, the paddy field is ready for transplantation of rice seedling and fish seed stocking. However, the stocking of fish seed is done after 10-15 days of transplantation of rice seedling from its nursery bed.
Rice varieties used for integrated/ or rice cum fish culture system:
The most promising deep water rice varieties chosen for different states are PLA-2 ( Andhra Pradesh ) , IB-1, IB-2 , AR-1, 353-146 ( Assam ) , BR-14, Jisurya ( Punjab ), AR 61-25B, PTB-16 ( Kerala ) , TNR-1, TNR (Tamil nadu), Jalamagan (Uttar Pradesh), Jaladhi-1, Jaladhi-2 (West Bengal) and Thoddabi (Manipur).
Manoharsali rice variety seeds are used in rice fields where the fishes are reared.
The paddy plots should be renovated suitably for the purpose of paddy cum brackish water aquaculture. Construction of an earthen dyke surrounding the paddy plot is essential for retaining water and also for holding the fish and shrimp during aquaculture. The height of the dyke is required to be maintained between 50 and 100 cm depending upon the topography of the plot and tidal amplitude at the site. A perimeter canal is necessary on the inner periphery of the plot. For a one ha paddy plot, the width and depth of the canal may be about 2 m and 1 m respectively. The earth removed from excavating the canal may be utilized for constructing or strengthening the dyke. In addition to the perimeter canal, two cross trenches of about 1 m width should also be constructed at both the directions. The bottom of the trenches should be above the perimeter canal so that during the course of desalination, entire water can be easily removed to the canal. The area covered by the perimeter canal and the trenches will be about 12% of the total land area.
Flooding and Weeding of Paddy:
The paddy fields were flooded after transplanting. Care was taken to keep the water level at a minimum of 5cm to allow proper filtering therefore, the water level was kept at 30 -50 cm deep, until the rice matures. The weed control measures was adopted by manual method by uprooting the weeds on both side of the plots of cultivated rice and it was carried out twice/ or thrice in a week. Chemical method of weed control was excluded or avoided to ensure that elements or agents capable of causing pollution to the ponds /or mortality of fish were extensively avoided.
Fertilization of Rice Fields:
The plots utilized for rice-cum-fish culture is mainly based on organic fertilization with a varieties of animal excreta such as poultry dropping, pig excerta, cow dung and waste of plants such as rice husks, waste product of local beer and ashes from household brunt and remains of burnt straws after the harvest is over and compost fertilizer like decomposed straws, weeds and rice stalks etc. The Fertilization of the paddy rice field is mainly practiced and was done with cow dung at the rate of 10 kg /50 m2 biweekly. This was done by broadcasting the fertilizer evenly on the fields from various points of the dykes.
Source of fish seed:
The progressive fish farmers who normally produce adequate size of fish seeds by rearing in small size ponds for a period of about 1-2 months and sell it to the farmers who grow them directly in paddy fields and farms.
Stocking of fish seeds:
Before releasing of fish seed to paddy field the paddy transplantation from rice seed beds to main paddy fields is done in the month of April, and there after paddy is left for two weeks for strengthening of paddy roots, the fish seed @ 2500 nos./ha area is released. The fish rearing period varied from 3-6 months and the paddy rearing period is 5-7 months.
Stocking of Fish Fingerlings:
The fish fingerlings initially of mean weights upto 20g- 35g respectively were stocked at 200 fish / 50m2 paddy respectively after flooding.
Water Quality Monitoring:
Water quality parameter was measured monthly. Turbidity was measured with a seechi disc at the refuge trench. pH was determined with a pH meter equipped with temperature probe. Conductivity of the water was measured with a multi-range conductivity meter. The dissolved oxygen (DO) was determined with dissolved oxygen meter. Plankton population densities in water were determined in accordance with the standard methods described by APHA (1980).
Feeding of stocked fingerlings: Feeding of the stocked fish in the paddies started immediately after stocking at established feeding spots. The fish were fed once in a day. The desired required proximate composition and quantity of the feed ingredients were must be given to the fingerlings at proper scheduled period.
Monitoring of growth rate of fish in the pond was carried out by randomly arching the fish using a hand net. The timely weight and the measurements were taken and the fish returned to the trenches. Feeding rates were adjusted accordingly. Feed was used to attract the fish before each sub-sampling. The mean growth rates (MGR) were calculated for the fish species according to the method of Wayne and Davis (1977).
Gears use for harvesting fishes is simple bamboo made basket called cane/bamboo. The fish culture for the period of 3-4 months in rice field, a production of 200-300 Kgs/ha achieved and while fish grown for the period of 5-6 months; 400-500Kgs/ha yield has been reported in the same season. Methodology used for harvesting used for harvesting, first the water is drained through outlet pipe, and thus allowing fishes and water accumulated in mid channel of paddy field, thereby the fishes are caught with the help of tasing puda, hand picking etc. and then stocking in large plastic bucket in live condition. After completion of fish harvesting the paddy harvesting followed. Normally paddy harvesting is made last part of Sept. & Oct. The paddy production range from 3500-4500 Kgs/ha from the same plot of land.
Fish harvested from the paddy field are marketed at the local market a live or fresh condition because of high market demand, live fish sold @ Rs. 150-200/- per Kg and fresh fish @ 100-120/- per Kg. during the lean season, the market price fluctuates. Marginal fish farmer sell their produce in fish market or in the paddy field itself. During the peak season, the fish production from these paddy fields also reaches in the capital markets. During the due rearing period paddy and fish no chemical insecticide/ pesticide/ fertilizer apply in the entire paddy field.
The rice-fish culture is an innovative farming system in which, rice is the main enterprise and fish fingerlings are taken as additional means to secure extra income. Rice- fish culture reduces poverty of the farmers and also improves the yield,create employment opportunity, and increase nutrient intake which brings food security for them. The farm-specific variables used to explain income indicate that farmers, who are of young aged, with larger farm size and better infrastructural facility – are able to earn more income.Proper policy and planning, positive attitude of administrators and extension workers, free access to information/training facilities for the farmers, required size of fingerlings at reasonable prices at the appropriate time will encourage the farmers to practice rice-fish culture largely on a broad spectrum scale.