Synergistic Effects of Onion Biowaste and NPK Fertilizer on Productivity and Profitability of Pak Choi

Applying inorganic fertilizer is essential for improving crop productivity. However, excessive usage of inorganic fertilizer may lead to soil acidification and have a substantial impact on plant development. The application of onion biowaste fertilizer with combination of NPK fertilizer on pak choi has been explored as a potential replacement for the use of fully inorganic fertilizer. This study investigated the effects of combining onion biowaste with NPK fertilizer on the productivity and profitability of pak choi (Brassica rapa var chinensis). The experiment was conducted in a greenhouse using a Randomized Complete Block Design (RCBD) with five treatments and five replications. The treatments used were T0 which is control (100% NPK fertilizer), T1 (100% peel onion fertilizer), T2 (50% NPK fertilizer + 50% peel onion fertilizer), T3 (30% NPK fertilizer + 70% peel onion fertilizer), and T4 (70% NPK fertilizer + 30% peel onion fertilizer). Yield parameters measured included fresh weight and biomass weight. Economic analysis was included gross margin, gross profit margin and benefit cost ratio. T2 and T3 produced the highest biomass weight with 185.00 g per plant and 170.30 g respectively. Concerning on economic analysis treatment T2 (50% NPK fertilizer + 50% peel onion fertilizer) consistently outperformed other treatment with gross profit margin of 58.54% compared with other treatment. These findings demonstrate that onion biowaste, when used in combination with NPK fertilizer, can effectively enhance plant performance while reducing reliance on inorganic fertilizers. This approach offers a sustainable and cost-effective alternative for small-scale farmers, promoting environmental benefits by reducing fertilizer-related pollution and utilizing household onion waste for agricultural use.