Integrated Aquaculture-Hydroponics System with Paddy Nursery on Aquaculture Pond

Abstract

Large areas of land remain uncultivated after the rainy season due to lack of irrigation facilities in many countries. There are also low lying areas, which remain waterlogged for the major part of the year. The returns from these areas in terms of agricultural crops and revenues are very poor. Adoption of integrated farming technology by incorporating aquacultural ponds in these areas has been found to increase the total yield and fetch higher financial return. Through aquacultural-hydroponic system, by using floating nurseries on aquacultural ponds, many benefits can be obtained, e.g., double use of pond water, control of erosion of the dykes due to wind action, fishes get shade during hot summer days, reduces labour cost, minimizes the loss of pond water due to evaporation, control poaching of fishes, etc. In this study, floating structures of different sizes for the aquacultural tanks were designed and fabricated and used for paddy nursery. The designed outer diameter of PVC hollow pipes (material used for making the floating structures) was found to be 3.0 cm and 4.5 cm for 0.15 m $^2$ and 0.3 m $^2$ of floating structures respectively. The optimum area of the floating structures and the number of fish in the tank were 40% and 42 fish/m $^2$ respectively after maintaining 5.38 mg/L of dissolved oxygen. Tilapia (Oreochromis mossambicus) fish and rice plant were found to grow well in the same tank and the total profit in integrated farming was $15,000 per ha of surface area of the pond per year.