Enhancing Shallot Growth and Yield in Ultisols through Coffee Husk Compost and Nitrogen Dosage Variations

Abstract Fertilization is crucial for the growth and productivity of shallots ( Allium ascalonicum L.). Both synthetic and organic fertilizers supply necessary nutrients for crop production. Coffee husk waste can be used to produce compost that provides both macro and micronutrients. This research aims to determine the optimal combination of synthetic fertilizer and coffee husk compost for shallot growth and yield. The study was conducted in Talang Kering, Kandang Limun Village, Muara Bangkahulu District, Bengkulu City, Indonesia. A Completely Randomized Design (CRD) with six treatments was used: no coffee husk compost + 92 kg N/ha; 5 tons/ha coffee husk compost + 73.6 kg N/ha; 10 tons/ha coffee husk compost + 55.2 kg N/ha; 15 tons/ha coffee husk compost + 36.8 kg N/ha; 20 tons/ha coffee husk compost + 18.4 kg N/ha; and 25 tons/ha coffee husk compost without N. Data were analyzed using the F test at a 5% significance level, with further analysis using LSD at 5%. The study found no significant differences among treatments in plant height and number of shallot leaves. Shallots fertilized solely with synthetic fertilizer without compost had lower shoot and bulb dry weights than those with coffee husk compost. Various combinations of coffee husk compost and N fertilizer produced similar shallot growth and yield. Thus, adding coffee husk compost improves shallot growth, which is promising for reducing synthetic fertilizer use and promoting sustainable agriculture.