Solar PV and IoT-integrated smart irrigation system with secure cloud control and water recycling

Frequent load shedding in rural farming areas, continued dependence on diesel pumps, and inefficient manual irrigation methods contribute to increased water wastage and carbon emissions. These challenges highlight the need for a smart irrigation system that can reduce grid and fossil-fuel dependence while improving water-use efficiency in small and medium scale farms. This paper presents a solar-powered Internet of Things (IoT)-based smart irrigation system designed to enhance water and energy efficiency in such agricultural settings. The proposed system integrates an ESP32 microcontroller with soil moisture, water level, and temperature sensors to enable automated irrigation using threshold-based control logic. Secure communication is implemented via the Message Queuing Telemetry Transport (MQTT) protocol with Transport Layer Security (TLS), supporting reliable data transmission, real-time monitoring, and remote operation through a web-based dashboard. The system supports both AUTO and MANUAL modes, including a manual override, to enhance operational flexibility. The photovoltaic (PV) subsystem was validated using PVsyst simulations, demonstrating an annual energy yield exceeding 5 MWh and a performance ratio of 83%. Field testing confirmed that the controller maintained soil moisture within the optimal range of 30–60% while preventing pump dry-run through tank-level interlock mechanisms. Long-term reliability of the solar subsystem was further supported by seasonal energy distribution analysis and P50–P90 probability assessments. Additionally, the system incorporates a drainage and water-recycling mechanism to minimize water waste. Overall, the results indicate that the proposed solution is a cost-effective, scalable, and off-grid-capable irrigation system suitable for sustainable agriculture in resource-constrained regions.