Asian Journal of Research in Agriculture and Forestry

Fertilization is one of the key factors in soybean cultivation to increase growth and yield, particularly when using organic materials such as compost and inorganic fertilizers like SP-36. The study aimed to evaluate the effect of compost and SP-36 fertilizer on soybean growth and yield. This research was conducted from October 2024 to February 2025 in a farmer farm at Bentiring Permai Village, Bengkulu City, Indonesia at an altitude of 24.7 m above sea level. The experiment was arranged in a factorial Randomized Complete Block Design (RCBD) with three replications and two factors. The first factor was the dose of water hyacinth compost, with levels as follows 0,15, 30, and 45 tons/ha. The second factor was the SP-36 fertilizer dose, with the following levels: 0, 70, 140 and 210 kg/ha. The study demonstrated that water hyacinth compost significantly influenced several growth and yield variables of soybean. The water hyacinth compost at 45 tons/ha had a notable positive effect on plant height, number of leaves, number of branches, shoot dry weight, root dry weight, number of filled pods, and seed weight per plant. Increasing compost doses resulted in a linear improvement across all observed variables. The control treatment (0 ton/ha) consistently showed the lowest values for all parameters, while at dose of 45 tons/ha produced the highest plant height, number of leaves, number of branches, shoot and root dry weight, number of filled pods, and seed weight per plot. In contrast, the application of SP-36 fertilizer did not significantly affect any of the observed variables. These findings highlight the potential of water hyacinth compost as a sustainable soil amendment that can significantly improve soybean productivity in Ultisol soils.