Stephen Okwang, Younggu Her, Taeil Jang
ABSTRACT Accurate monitoring of crop water use is critical for precision irrigation, yet conventional lysimeter systems remain too costly and complex for widespread adoption. This study presents the development and field validation of a low‐cost, information and communication technology (ICT)‐enabled weighing lysimeter system that integrates load cells, soil moisture sensors and cloud‐based data logging for real‐time water use monitoring. The system was deployed in buckwheat ( Fagopyrum esculentum ) fields in South Korea to evaluate performance under practical conditions. Continuous measurements of crop evapotranspiration (ET c ) and soil moisture were successfully captured, and growth‐stage crop coefficients (K c ) derived from these data (0.65, 1.05 and 0.73 for initial, mid‐ and late‐season, respectively) were consistent with literature benchmarks, confirming the system's reliability. Beyond validation, the platform demonstrated responsiveness to rainfall and radiation fluctuations, highlighting its utility for adaptive irrigation scheduling. Fabrication costs were significantly lower than conventional lysimeter installations, underscoring its scalability for smallholder and resource‐limited settings. By combining affordability, modular design and Internet of Things (IoT)‐enabled monitoring, this smart lysimeter provides a practical pathway for precision irrigation and digital agriculture, extending advanced monitoring capabilities to a wider range of crops and farming systems.