Assessment of the TEROS 10 and TEROS 12 sensors in soil moisture measurement

Agricultural University of Athens, Department of Natural Resources Management and Agricultural Engineering, 75 Iera Odos Str., 11855 Athens, Greece

^* Corresponding author: athfrag@aua.gr

Abstract

This study focuses on investigating the accuracy of the empirical equations proposed by the manufacturing company for the widely used TEROS 10 and TEROS 12 sensors. Specifically, the study examines whether the raw - unprocessed - measurements provided by the two sensors lead to reliable predictions of soil moisture and electrical conductivity values when these particular empirical equations are utilized. For this purpose, a prototype setup was developed, incorporating a lowcost microcontroller along with auxiliary power supply and data acquisition circuits for the sensors. The results highlight the need for specific calibration of the sensors for each soil type and salinity level. Additionally, the behaviour of the sensors operating at low frequency (70 MHz) under increasing salinity conditions is contrary to expectations.