Relationship between the Productivity and Nutrient Profile of Bottom Soils of Selected Regular and Integrated Fish Ponds in Ibadan, Nigeria

Abstract

Water quality management has been considered one of the most important aspects of pond aquaculture for many years, but less attention has been given to the management of pond bottom soil. The quality of pond bottom soils greatly impacts the productivity of ponds with respect to fish production. The objective of this study is to explain the nutrient profile of bottom soils of selected regular and integrated ponds in the Ibadan metropolis, Oyo State, Nigeria. Bottom soils and water samples of three regular and three integrated ponds in Ibadan  metropolis, Nigeria were sampled. In each pond, soil samples were sampled from two different points at three depths each (inlet and outlet) of 0-10cm,10-20cm and 20-30cm. Soil samples were also analysed for; pH, organic carbon, organic matter, nitrogen, phosphorous and potassium. The productivity of the ponds was evaluated using the measured parameters in line with standard procedures. The data obtained were analyzed using descriptive statistics, one-way analysis of variance, correlation and regression analysis.  The organic carbon of all the ponds indicated that they were all suitable for aquaculture production with average values ranging from 0.82% to 2.66%. Three of the ponds’ bottom soil were of mineral soils having medium organic carbon of mean values 1.81%, 1.73% and 2.66% for integrated pond 3, regular ponds 1 and 3 respectively while the three other ponds were of organic soils having high organic carbon concentration of mean values 1.06%,0.82% and 1.01% for integrated ponds 3and 2 and regular pond 2. The pond soils were all neutral except two of the regular ponds with average values ranging from 7.00 to 9.60. All the mean values of phosphorous in the soil indicated that the soils were of high productivity and highly suitable for aquaculture production. Mean soil phosphorous concentration values 0.33%, 0.30%, 0.26%, 0.27%, 0.28% and 0.34% of integrated ponds 1 to 3 and regular ponds 1-3 respectively showed that the ponds were highly suitable for fish culture with respect to ability to synthesize phytoplankton and zooplanktons. The organic carbon concentration and the phosphorous concentration of all the ponds showed high productivity. The pH and the nitrogen concentration of all the ponds showed high productivity.  Generally, the evaluation of the ponds in line with the three standard procedures indicated that the integrated pond soils was more productive for fish culture than the regular pond soils.