EFFECT OF DIFFERENT FERTILIZER RATE ON BIOLOGICAL PRODUCTIVITY AND WATER QUALITY OF ACID SULFATE SOILS FISHPOND

Abstract

An experiment was conducted in order to evaluate the effect of different
fertilizer regimes on biological productivity and water quality of limed acid sulfate
soils fishponds. The experiment consisted of 4 different fertilizer treatments i.e.,
control without fertilizer input, chicken manure 50 g/m
2
/week, chicken manure 75 g/
m
2
/week, and inorganic fertilizer (6 g of urea + 3.5 g of TSP /m
/week), each
treatment with 3 replications. Result of experiment shows that Inorganic fertilization
gave the highest chlorophyll a
concentrations (83.40 mg/m
3
), and the highest net fish
yields 7.53 kg /ha /day), but had a lower water pH than that in control. Ponds which
are fertilized with chicken manure 75 g /m2 /week gave the highest fish survival rate
(100%) while in ponds without fertilizer inputs only 3.3 % of stocked fish was
survived.