Precision and accuracy of DFM soil water capacitance probes to measure temperature

Precision and accuracy of DFM capacitance probes with temperature sensors were evaluated for measuring temperature. Two sets of DFM probes were used in this experiment, one set of 17 for testing the performance of the temperature sensors and the other set of 16 probes to evaluate how to improve the accuracy of measurements of the DFM temperature sensors. Standard deviation (SD) as a measure of precision shows that the range of precision for the all the observations was 0.15-1.08 °C. The accuracy of the device, using means of the absolute errors, for measuring temperature was ±1.28 °C. The DFM temperature sensors were able to measure temperature with high precision while the accuracy of the measurements was improved with calibration procedure. The accuracy was improved up to ±0.06 °C with the calibration procedure. It was concluded from the study that the device is suitable for measuring temperature effectively. Using equation derived during calibration procedure before installation of the device will increase sensors performance in terms of temperature measurements accuracy. The DFM capacitance probe is durable, with easy logging, and data management of high accuracy and precision or repeatability. It can also simultaneously collect data on multiple parameters such as soil water and soil temperature.