Methods to correct temperature-induced changes of soil moisture sensors to improve accuracy.

Accurate soil moisture measurement is critical for precision irrigation management when using sensor data to calculate application timing and volume. Especially under conditions with soil varying temperature, sensors performance is always subject to some degree of error. This research investigated the method to assess soil moisture sensors performance across temperature gradient (4 °C to 14 °C) in sandy soil. Soil moisture was maintained stable, temperature was increased gradually and ΔVWC was measured for each increment across temperature. Results showed a linear decreasing trend between temperature rise and ΔVWC by 0.02 and 0.015 cm/cm for Teros-12 and 10-HS sensors while SoilWatch-10 exhibited a promising increasing trend. The observed (Oθ) and temperature-corrected (TCθ) VWC were compared through regression model and sensors performance was assessed through statistical metrics including Root Mean Square (RMSE), Index of Agreement (IA) and Mean Biased Error (MBE).•The RMSE values of 0.015, 0.011 and 0.031 cm/cm respectively for Teros-12, HS-10 and SoilWatch-10. This indicates that 10-HS exhibited the highest accuracy, followed by Teros-12, and lastly SoilWatch-10 sensor.•Strong agreement (IA = 0.99) between Oθ and TCθ showed the reliability of all sensors.•Teros-12 and 10-HS sensor showed slight under estimation (MBE = -0.014 and -0.011), while SoilWatch-10 indicated overestimation (MBE = 0.028).Thus, temperature correction is crucial for improving accuracy and minimizing over and/or underestimation ensuring precise detection of VWC by temperature-induced sensors.