Pengaruh Pelapisan Pupuk Kompos Berbasis Beeswax dan Gypsum Terhadap Karakteristik Pelet Kompos dan Pertumbuhan Bawang Merah (Allium cepa L. var aggregatum)

Abstract

Shallots (Allium cepa L. var. aggregatum) are an important horticultural crop requiring efficient fertilization to improve nutrient use efficiency and crop productivity. One approach is the development of slow-release compost pellets coated with natural materials such as beeswax and gypsum. This study aimed to evaluate the effects of beeswax–gypsum coatings on the physical characteristics of compost pellets, nutrient release based on Electrical Conductivity (EC), and the growth and yield of shallots. A Completely Randomized Design (CRD) consisting of eight treatments and four replications was applied. Observed variables included coating thickness, particle density, bulk density, compressive strength, vibration resistance, water absorption, nitrogen content, EC, and plant growth and yield parameters. The results showed that the beeswax–gypsum coating improved the physical characteristics of compost pellets by increasing bulk density to 0.76 g cm⁻³ and reducing water absorption. Nutrient release occurred more gradually in coated pellets, with the lowest initial EC recorded in the 75% beeswax + 25% gypsum treatment (1,063 μS/cm). In the plant experiment, the same treatment produced the highest bulb weight per plant (6.40 g per plant) and bulb diameter (22.46 mm), whereas the combination treatment (P7) resulted in the highest bulb weight per clump (34.68 g per clump). These findings indicate that beeswax–gypsum-coated compost pellets have good potential as environmentally friendly slow-release fertilizers for improving nutrient availability and shallot production.