PRODUKSI TINGGI HARGA TETAP BERGEJOLAK: DINAMIKA DAN POLA MUSIMAN HARGA BAWANG MERAH DI JAWA TENGAH (2021-2025)

Abstract

Red onion price instability remains a persistent agribusiness problem even in major production centers, indicating that high aggregate output does not automatically ensure stable supply throughout the year. This study analyzes price dynamics, relative fluctuations, seasonal patterns, and long-term trends of consumer red onion prices in Central Java during January 2021–December 2025. Monthly price data comprising 60 observations were obtained from the National Food Agency and the Central Java Office of Industry and Trade, with the 2025 series harmonized using an overlapping-period linking procedure. The analysis employed descriptive statistics, coefficient of variation, seasonal indices, the Augmented Dickey–Fuller test, linear trend regression, a trend model with monthly seasonal dummies estimated using HAC Newey–West standard errors, and STL decomposition. The average price was IDR 33,391/kg with an overall coefficient of variation of 24.18%. Annual price variability was highest in 2024 (26.08%), while 2025 recorded the highest average price but a lower coefficient of variation (11.81%). Seasonal indices peaked in June (116.84) and reached the lowest level in September (81.20). The trend-seasonal model estimated a significant upward trend of approximately IDR 219.09/kg per month, with an R² of 0.473, while the joint seasonal effect was statistically significant. These findings reveal a production–price stability paradox: high production capacity does not guarantee price stability when supply is uneven across months. Price stabilization therefore requires calendar-based supply management, stronger postharvest and storage systems, interregional distribution, and forward-looking market information.