Agrowaste-Derived Liquid Organic Fertilizer and Temperature Stabilization in Vertical Aeroponics for Crop Production

Sustainability challenges in hydroponic and aeroponic systems are primarily due to the limited use of liquid organic fertilizers (LOFs) and the suboptimal temperature conditions for plant growth. This study aims to address these issues by incorporating agrowaste-derived LOFs as an alternative nutrient source and utilizing a clay-dominant soil layer in the vertical aeroponic system to stabilize nutrient solution temperatures. The goal is to optimize both the productivity and efficiency of LOFs. Eight LOFs were developed using mustard oil cake, sugarcane, and kangkong leaves, and assessed on various parameters. Among these, formulations F6 and F4 exhibited optimal pH (4.50 and 5.0), electrical conductivity (18.20 and 18.10 dS/m), elevated levels of nitrogen (0.19% in both), phosphorus (0.017% and 0.018%), and potassium (1.10% in both). To address temperature fluctuations in the nutrient solution, a 1.5-in. layer of silty clay soil effectively stabilized nutrient temperatures, reducing variation from 30.90°C to 27.50°C in summer and from 22.63°C to 19.57°C in winter. Leafy vegetable Kangkong (Ipomoea aquatica) was used in this study, where various growth and nutritional parameters were evaluated over 45 days to assess the impacts of various treatments. Plants grown with liquid organic fertilizer F4 (treatment T4) achieved a yield of 484.80 g/unit plot, which was comparable to the non-organic treatment T2 at 505.30 g/unit plot with similar nutritional quality. These findings demonstrate that agrowaste-derived LOFs can serve as a sustainable alternative to synthetic fertilizers in aeroponic systems, offering both environmental and agronomic benefits.