Abstract:
The study was taken up to develop and evaluate an automated, IoT-based drip irrigation
and fertigation system for a vertical farming structure. First, the hydraulic performance of three
fertigation equipment units was tested; the ¾-inch Venturi injector achieved a maximum suction
rate of 3.6 to 3.7 L/min at 0.6 kg/cm² pressure, outperforming the positive-displacement flow
restrictions. Second, testing the vertical drip system hydraulics showed that increasing operating
pressure from 0.2 to 1.0 kg/cm² gave an emission uniformity in the range 60.1% to 69.3% across
the vertical tiers. Third, to prepare for smart dosing, the 3-in-1 NPK sensor was calibrated using
soil samples analyzed by the District Soil Testing Laboratory, Malappuram, generating highly
accurate correction equations (R2 = 0.9706 for N, R2 = 0.8812 for P, and R2 = 0.8817 for K).
Finally, the fully integrated ESP32 automation system successfully monitored a microclimate
environment of 27.2°C temperature and 86% humidity. It demonstrated precise closed-loop
control by automatically activating the main water pump, while successfully keeping all three
nutrient dosing valves turned off when the real-time soil fertility readings remained safely above
the minimum programmed baseline thresholds and turned on when it was below the threshold
levels. Thus an Internet of Things (IoT)-based fertigation system was developed and tested in the
field to enable automated and precise application of irrigation water and fertilizers based on real-
time field conditions.
