Integrated application of compost and potassium fertilizer enhances soil fertility and stevia productivity in Inceptisols

Inceptisols is among the predominant soil types in Indonesia; however, they are characterized by low fertility, which constrains their agricultural productivity.To address these limitations, this study aimed to assess the effects of organic amendments and K fertilization on the soil chemical properties and growth performance of stevia.A factorial randomized block design was employed, incorporating three types of compost: No compost, rice straw compost, and leucaena compost, combined with four levels of KO application (0, 75, 150, and 225 kg/ha).Soil parameters (pH, EC, CEC, and exchangeable K) and plant traits (height, biomass, and total soluble solids -TSS) were assessed.Both compost types significantly improved soil chemical properties, with leucaena compost yielding the highest pH and nutrient availability.Potassium fertilization significantly increased plant biomass, K uptake, and TSS content, particularly at 225 kg KO/ha.The combined application of organic and inorganic fertilizers yielded the most favorable outcomes for both soil health and stevia productivity.These findings underscore the complementary benefits of integrating organic and inorganic fertilization strategies to optimize stevia cultivation.This approach enhances soil health and nutrient availability, promotes sustainable agricultural practices, and contributes to addressing the national sugar supply gap by producing healthier natural sweeteners.Future studies should focus on long-term field trials to assess the residual effects of compost application, track changes in soil microbial communities under prolonged integrated fertilization, and evaluate the agronomic and economic feasibility of scaling up these practices across diverse agroecological regions.