Nitrogen fertilizer effects on production of Tilapia in ponds fertilized with phosphorus and potassium

The effect on Tilapia aurea production of 15 biweekly applications equal to 22.5 kg/ha of 0-20-5, 5-20-5, and 20-20-5 fertilizers was tested in ponds. Averages of fish production were with 0-20-5 fertilizer, 651 kg/ha; with 5-20-5, 947 kg/ha; and with 20-20-5, 930 kg/ha. Increased fish production in ponds fertilized with nitrogen resulted from the favorable influence of nitrogen on plankton production. Moreover, the two higher rates of nitrogen application (5-20-5, 20-20-5) were about equally effective in increasing plankton and fish production.