Researchers at Osaka Electro-Communication University published a field study combining an ESP32-based environmental module with a three-point soil-moisture sensor. The system monitored weather and root-zone conditions while the team measured broccoli height and leaf counts.
The April 2026 paper analyses observations from a 15-square-metre plot in Osaka during March–April 2025. Its regression analysis found solar radiation influential, while moisture in the middle measured soil layer contributed positively to plant height. The design aims to capture changes that a single-depth observation may miss.
The authors explicitly note that their calibration and models are specific to the experimental soil, with broader validation still required. The study supports further investigation of inexpensive depth-resolved monitoring; it does not establish a universal irrigation prescription for broccoli growers.
