IoT enhanced deep water culture hydroponic system for optimizing Chinese celery yield and economic evaluation

Abstract

This study examined the integration of a deep-water culture hydroponic system with Internet of Things (IoT) technology using Blynk and ESP32 microcontrollers for Chinese celery cultivation. Four experimental setups in 2 x 6 meter greenhouses with 1.2-meter high planting shelves were tested, comprising 1) combined light and temperature control, 2) temperature control, 3) light control, and 4) natural conditions. A 45-day experiment was conducted under equal electrical conductivity (EC) and pH levels across all greenhouses. Light control utilized artificial light at a wavelength of 660 nm from 6:00 PM to 11:00 PM, while temperature control employed a misting system activated when temperatures exceeded 35°C. Data collected every 5-7 days were analyzed using the Friedman test. The fully controlled greenhouse yielded 13.91% more than natural conditions, 30.3 kg vs 26.6 kg, with significant weight differences (χ² = 8.850, p < 0.05) approximately 25 days after planting. Economic analysis revealed that the controlled greenhouse yielded the highest net profit of 750.18 USD per year with a 13-month payback period, whereas the natural conditions greenhouse demonstrated the highest return on investment (ROI) of 131.00% and the shortest payback period of 9 months, despite producing the lowest yield. The results demonstrate that IoT-controlled environments can significantly increase crop yields, though economic viability may vary.