Ecological study of fish ponds in relation to fish production by adding some organic and inorganic substances
1985
Satit Kovitvadhi
Results showed that the leaf and stem of groundnut, water hyacinth and straw mixed and fermented with cow manure increased average pH, the percentage of nitrogen, phosphate and potassium. In contrary, the percentage carbon and C/N ratio decreased. For the chemical properties of soil in ponds, the average pH, percentage of nitrogen, organic matters and phosphate increased, but percentage of potassium decreased. All treatments and replications regarding physico-chemical properties of water in fish ponds were in favourable range for fish growth. The number per unit in each treatment were 9.67-38.93 phytoplanktons/litre, 76.64-139.7 zooplanktons/litre and 554.36-1,441.74 benthose/m2. Total gain in live body weight (harvested weight minus stocking weight) of Tilapia nilotica, Puntius gonionotus and Labeo rohita in chemical fertilizers, fermented groundnut, water hyacinth and straw, cow manure and control treatment were 22.42, 21.16, 20.48, 23.70 and 15.59 kg./rai/4 months, respectively. There were no significant differences (P 0.05) between the biological and physical factors both water and mud in experimental fish ponds for all treatments. In addition, certain quantities of dieldrin insecticide were detected in all three species with an average of 0.023-0.102 mg/kg
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