Effects of different manure levels on fish growth, mortality and yield in a horizontally-integrated fish-cum-poultry farming system in Nigeria |
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| Authors: | D C Njoku |
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| Institution: | College of Agriculture and Veterinary Medicine, Imo State University, Owerri, Nigeria |
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| Abstract: | Optimum manure rate in horizontally-integrated fish ponds, using poultry droppings, was evaluated in two agricultural zones of Imo state of Nigeria between July 1994 and January 1995. It was aimed at resolving the problem of frequent cases of excessive algal blooms, oxygen depletion and stress-related mortalities in fish ponds. Results indicate that poultry droppings, applied at the rate of 5000 kg ha?1 per year gave the best yield (23.5 M.t ha?1 for Heterobranchus bidorsalis Geofrey St Hillaire, 1809; and 11.2 tons ha?1 for Oreochromis niloticus Linnaeus, 1758), higher fish recovery and optimum tolerance levels of the physico-chemical parameters of water for fish growth. The estimated costs of production at this level of fertilization were  2 734 000.00 per hectare (equivalent to US$33 351.5), with the highest net revenue of 1 555 000.00 (US$18 963), and a cost: benefit ratio of 1: 2.3. This implies that for every 1.00 (US$0.01) invested in the production system at this rate of pond fertilization, the highest net profit of 1.30 (US$0.02) accrued to the farmer compared with any other manure load of the pond. |
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