The effect of addition of fish bone meal on the concentration of nitrogen (N), phosphorus (P), and potassium (K) in seaweed liquid organic fertilizer of Gracilaria sp.

Gracilaria sp. contains macro and micronutrients needed by plants, such as phosphorus, potassium, calcium, magnesium, manganese, zinc, and boron. Seaweed-based liquid organic fertilizer currently on the market has low phosphorus and potassium content. One ingredient that can increase phosphorus and potassium content is fishbone. This study aimed to determine the effect of fishbone meal addition to Gracilaria sp. liquid organic fertilizer on the concentration of nitrogen, phosphorus, and potassium. The method used in this study was the experimental method with four treatments and five replications on each treatment. These treatments were P0 (0% fish bone meal), P1 (25% fish bone meal), P2 (50% fish bone meal), and P3 (75% fish bone meal). The main parameters in this study were the concentration level of nitrogen, phosphorus, and potassium. The addition of fishbone meal increased nitrogen, phosphorus, and potassium concentration. The highest nitrogen, phosphorus, and potassium contents were found in the treatment with the addition of 75% fish bone meal, producing 0.69% nitrogen, 0.42% phosphorus, and 0.43% potassium content.