Affiliations: Section for Environmental Engineering, Aalborg
University, Sohngaardsholmsuej-57 DK-9000 Aalborg. E-mail: ps@bio.aau.dk | Aquacultural Engineering Section, Agricultural &
Food Engineering Department, Indian Institute of Technology, Kharagpur-721 302,
India
Note: [] a
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.
