Interactive Effects of Multi-Source Liquid Organic Fertilizer And Goat Manure Dosage on Growth and Yield of Purple Eggplant (Solanum melongena L.)

Background: Declining purple eggplant (Solanum melongena L.) production associated with soil degradation from excessive inorganic fertilizer use may be mitigated through organic-waste-derived liquid organic fertilizer (LOF) and goat manure to improve soil fertility and reduce dependence on chemical fertilizers. This study aimed to determine the effects of combining LOF concentration and goat manure dosage on the growth quality of purple eggplant. Methodology: A factorial experiment was conducted using a Completely Randomized Design with two factors. The first factor was LOF concentration derived from banana peels, moringa leaves, onion peels, and tofu pulp, consisting of NPK as the control and LOF at 100, 150, and 200 mL L⁻¹. The second factor was goat manure dosage consisting of soil as the control and 700, 900, and 1,100 g plant⁻¹. Data were analyzed using ANOVA, followed by the 5% HSD test. Findings: The NPK control produced higher values for several growth and yield parameters. However, the combination of LOF 200 mL L⁻¹ and goat manure 900 g plant⁻¹ significantly increased plant height and leaf number, reaching 79.70 cm and 50.78 leaves, respectively. Among organic treatments, LOF 150 mL L⁻¹ produced the highest fruit number (2.58 fruits plant⁻¹) and total fruit weight (353.67 g plant⁻¹). Goat manure at 900 g plant⁻¹ produced the highest fruit number (4.50 fruits plant⁻¹), whereas 1,100 g plant⁻¹ produced the highest total fruit weight (683.89 g plant⁻¹). The combination of LOF 150 mL L⁻¹ and goat manure 900 g plant⁻¹ produced the best response for fruit sweetness. Contributions: The findings support the potential of organic-waste-derived LOF combined with goat manure as an alternative nutrient management strategy for improving purple eggplant quality while reducing reliance on inorganic fertilizers.