Effect of Combined Liquid Organic Fertilizer and Azolla microphylla Compost on Growth and Yield of Bird’s Eye Chili (Capsicum frutescens L.) under Tropical Land Conditions in Indonesia

Abstract

Global demand for horticultural commodities, particularly Bird’s Eye Chili (Capsicum frutescens L.), continues to increase due to their function as a household food ingredient and a source of bioactive compounds with health benefits. In Indonesia, Capsicum frutescens are a strategic commodity that influences inflation, making increasing productivity a crucial part of national food security. However, low soil fertility and high dependence on inorganic chemical fertilizers hamper productivity while increasing production costs and environmental pressures. Sustainable fertilization using local organic resources is an important strategy to improve soil health and plant performance. This study aimed to evaluate the combined effect of liquid organic fertilizer (LOF) and Azolla microphylla compost on Capsicum frutescens growth and yield, by simultaneously assessing five parameters: plant height, stem diameter, number of leaves, number of branches, and fruit production. The experiment was conducted in Langgomea Village, Konawe, Southeast Sulawesi, with chili seedlings planted in 25 cm polybags containing a mixture of local garden soil and rice husk charcoal (2:1 v/v). A factorial Randomized Complete Block Design was applied with LOF (0, 10, 20, 40 ml/L) and compost (0, 10, 20, 40 g/plant), resulting in 16 treatment combinations, each replicated three times (a total of 144 plants). Growth and yield data were recorded weekly for 12 weeks; harvesting was carried out from the first to the last harvest. Statistical analysis using ANOVA and LSD at a significance level of 5% with R 4.3 and SPSS 28, provides a scientific basis for sustainable organic fertilization strategies and optimization of local resources. The results showed that the combination of LOF and Azolla microphylla compost significantly affected all growth and production parameters of Capsicum frutescens. The highest plant height was achieved in the P3K3 treatment (83.67 cm), followed by an increase in stem diameter to 136 mm, number of leaves to 104, and number of branches to 31.33. This increase in vegetative growth is in line with the high nitrogen and phosphorus content of Azolla, which supports cell formation, chlorophyll, protein, and nucleic acid synthesis. It was also found that Capsicum frutescens L. fruit production increased significantly with the combination of LOF and compost, reaching the highest average of 108.67 kg per plant in the P2K3 treatment. This confirms that the application of Azolla-based organic fertilizer provides sufficient nutrients, increases photosynthesis, biomass, and fruit yield accumulation. The interaction of liquid fertilizer and compost provides optimal synergistic effects for vegetative growth and plant productivity in the field. These findings bridge the research gap regarding the simultaneous use of liquid fertilizer and Azolla compost on Capsicum frutescens L., in humid tropical agroecosystems, while also providing practical implications for sustainable organic fertilization strategies. Application of these findings can improve resource efficiency, reduce dependence on chemical fertilizers, and support environmentally friendly tropical horticultural management. Keywords: Bird’s Eye Chili, liquid organic fertilizer, Azolla microphylla compost, fruit yield, humid tropical agroecosystem, sustainable fertilization.