Optimization
of fertilization rate for maximizing periphyton production on artificial
substrates and the implications for periphyton-based aquaculture
M.E. Azim, M.A. Wahab,
A.A. van Dam, M.C.M. Beveridge, A. Milstein, M.C.J. Verdegem-2001
Aquaculture
Research, 32(9): 749-760
Abstract:
The effects of four rates of application of
fertilizer, with cow manure (3000 kg ha-1), urea (100
(kg ha-1) and triple super phosphate (TSP) (100 kg ha-1)
(treatment F)), treatment F ×
0.5
(treatment 0.5F), treatment F ×
1.5
(treatment 1.5F) and treatment F ×
2
(treatment 2F), on periphyton, plankton and water quality in tropical
freshwater ponds were studied. The highest periphyton biomass in terms of
dry matter (3.27 mg cm-2 substrate), ash-free dry
matter (2.06 mg cm-2 substrate) and chlorophyll a
(7.49 µg cm-2 substrate) developed in treatment 1.5F. The
ash content of periphyton was lower in treatment 1.5F (38% of dry matter)
than in other treatments (57–66% of dry matter). Total ammonia and
chlorophyll a of water increased with fertilization rate. Treatment
1.5F (cow manure, urea and TSP at rates of 4500, 150 and 150 kg ha-1
respectively) appears to be the optimum, yielding high quantity and quality
periphyton. By supplying a substrate area for periphyton equivalent to the
pond surface, it was estimated that this level of fertilization could
support a fish production of around 5000 kg ha-1 y-1,
without recourse to supplementary food.
(Fish Culture and Fisheries Group, Wageningen
Institute of Animal Sciences, PO Box 338, 6700 AH Wageningen, Wageningen
University, The Netherlands. E-mail: ekram.azim@alg.venv.wau.nl)
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