EFFECTS OF POND FERTILIZATION ON THE PHYSICO-CHEMICALWATER QUALITYOFSELECTED EARTHEN FISHPONDS IN IFE NORTH LOCAL GOVERNMENTAREA, OSUN STATE, NIGERIA
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Date
2013-04-09
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Zoological Society of Nigeria
Abstract
The effect of fertilization on the physico-chemical water quality of six selected earthen fishponds in Ife North Local
Government Area of Osun State was investigated for a period of two years sampling the ponds every other month. The
fishponds were grouped with regard to fertilization practice and water flowage regime into three sets comprising two non-
flow-through ponds that received organic and inorganic fertilizers (FNF); two flow-through ponds that received the same
organic and inorganic fertilizers (FF) and two unfertilized flow-through ponds. The investigated water quality parameters
include water temperature, pH, transparency, dissolved oxygen, major ions, some plant nutrients and heavy metals using
standard titrimetric and instrumental methods of analysis.The mean values of these parameters were not statistically
different (p> 0.05) for the three sets of fishponds with the exception of sodium, Alkalinity, HCO3-, Conductivity and TDS
which were each characterized with significant mean differences (p= 0.05). In general, the fertilized ponds were characterized
by higher mean values in 24 of the 29 investigated water quality parameters than the non-fertilized ponds. Also the mean
values of 22 out of the 29 investigated parameters were generally higher in the flow-through ponds than in the non-flow-
through ponds. Increase in the parameters due to water flowage was statistically significant (p> 0.05) for sodium, alkalinity,
bicarbonate, conductivity and TDS while the effect of fertilization was higher for the dissolved oxygen parameters, nutrients
(NO3, PO4,), major ions and apparent colour. Thus, the fertilized ponds were more saline (based on conductivity and TDS),
better buffered and richer in nutrient than the unfertilized ponds. These effects were enhanced by flowage hence the
fertilized flow-through ponds were characterised by the most suitable water quality for fish culture in the study-area while
the fertilized non flow-through ponds was least suitable. The study revealed that to achieve the desired effect, pond
fertilization must be accompanied by adequate water flowage especially in shallow fishponds
Description
The Zoologist, Vol. 11, No 13, p.14-16
Keywords
water quality, fertilization, flow regime, fishpond, Nigeria