Application of organic fertilizer on swamps pond for catfish (Pangasius sp.) culture

Abstract

Swamp fish pond has a problems related to submerged flat soil and water pH value and result in low productivity of ponds. Fertilization increase productivity of pond water by providing nutrients for fish food organisms, The objective of this research was to determine the best dosage of organic fertilizer to improve water quality and pond productivity and it’s effect to survival and absolute growth of catfish Pangasius sp. The research was conducted with using completely randomized design with four treatments and three replications. All of ponds unit were limed using dolomite of 10 ton/ha, incubated for 13 days, then gave four difference dosage of organic fertilizer, that were without fertilizer (P0), with fertilizer of 100 g/m2 (P1), 170 g/m2 (P2), and 240 g/m2 (P3). Pangasius sp. fish (average body length of 5±0.5 cm) was stocked with the density of 15 fish/m2 and cultured for 30 days. The parameters observed were soil (pH, N, P2O5, Ca, and C-organic) and water quality (pH, alkalinity, temperature, dissolved oxygen, ammonia, total Phosphate, Ca, and TOC), pond productivity, density of phytoplankton, survival, absolute growth, feed efficiency, and production of fish. The data were statistically analyzed by one-way ANOVA, Least Significant Difference test, and regression models analysis. The results showed that P1 (100 g/m2 of fertilizer) was the best dosage indicated by pH 7.60, nitrogen 0.13%, P2O5 0.16%, Ca 2.59%, C-organic 1.49% of pond soil; pH 7.42, temperature 27.3-32.4°C, dissolved oxygen 4.94-5.09 mgL−1, alkalinity 51.33 mgL−1, Ca 55 mgL−1,TOC 12.3 mgL−1, ammonia 0.24 mgL−1, Total Nitrogen (TN) 3.78 mgL−1, Total Phosphate (TP) 0.109 mgL−1 of pond water. Based on TN:TP (10.09) of water showed nutrient was balanced. Productivity of ponds was on eutrophic state based on both TN and TP. Survival rate of catfish was 100%, absolute gain of weight 8.46 g and lenght 3.99 cm, Feed efficiency of fish was 101.55% and the density of phytoplankton was 217 cell/mL.