Effect of EM-4 Bioactivator Concentration and Chicken Manure Addition on the Quality of Anaerobic Bokashi Fertilizer Produced from Oil Palm Empty Fruit Bunch Waste

Abstract

Abstract. The utilization of oil palm empty fruit bunches (OPEFB) as raw material for organic fertilizer offers a sustainable approach to agricultural waste management while supporting circular bioeconomy practices. This study aimed to evaluate the effects of EM-4 bioactivator concentration and chicken manure addition on the quality of anaerobically produced bokashi fertilizer from OPEFB. A 3 × 3 factorial Completely Randomized Design (CRD) was employed with two factors: EM-4 concentration (7%, 12%, and 17%) and chicken manure proportion (10%, 15%, and 20%), each replicated twice. The quality of the bokashi fertilizer was evaluated based on moisture content, organic carbon content, and pH, followed by two-way analysis of variance (ANOVA). The results showed that moisture content ranged from 13.10% to 19.20%, organic carbon content ranged from 47.60% to 53.15%, and pH ranged from 7.78 to 9.81. ANOVA indicated that EM-4 concentration significantly affected moisture content and pH (p ≤ 0.01), whereas chicken manure proportion had a highly significant effect on organic carbon content (p ≤ 0.01). No significant interaction between EM-4 concentration and chicken manure proportion was observed for any measured parameter (p > 0.05). Overall, the bokashi fertilizer produced in this study met the Indonesian National Standard (SNI 7763:2024) for moisture content and organic carbon, while the average pH remained within the acceptable range for solid organic fertilizer. These findings demonstrate that EM-4 concentration primarily influences the physical and chemical characteristics associated with fermentation, whereas chicken manure serves as the principal contributor to organic carbon accumulation in bokashi fertilizer produced from OPEFB.