Reduction of Phosphorus fertilizer application in Warm-water fish ponds by using Phosphate solubilizing bacteria as biofertilizer

The aim of the present study was to investigate the possibility of replacing phosphorus chemical fertilizer (triple superphosphate) with biofertilizers as an environmentally friendly approach.  In this study, Possibility of replacing Triple superphosphate fertilizer with phosphate solubilizing bacteria "Pseudomonas deceptionensis Persian10 strain" in 10 treatments with two bacterial factors (in two levels of inoculation and non-inoculation) and chemical fertilizer (in five levels 0, 25, 50, 75 and 100% of the recommended amount of fertilizer in the pond) was examined in aquarium conditions. Treatments included: 1: 100% fertilizer + bacteria, 2: bacteria, 3: 25% fertilizer + bacteria, 4: 50% fertilizer + bacteria, 5: 75% fertilizer + bacteria, 6: 100% fertilizer, 7: 75% fertilizer, 8: 50% fertilizer, 9: 25% fertilizer, 10: control (without fertilizer and bacteria). Bacterial densities, soluble phosphorus, phosphatase and pH were measured on days 0, 2, 7, 12 and 17. The results showed that the phosphorus of all treatments had an increasing trend on different days and at the same time, an increase in the pH value and a decreasing trend was observed in the bacterial population and the amount of phosphatase enzyme. The highest amount of soluble phosphorus was observed in treatments 4 and 5. According to the obtained results, the application of 50% phosphate fertilizer + phosphate solubilizing bacteria can be recommended as a suitable ratio for the fertility of fish ponds and reducing the use of chemical fertilizers.