This paper presents the monitoring of the soil matrix potential using the electronic tensiometer. The trials were conducted at the Mechanics and Electronics Lab of the Department of Agricultural Engineering of the Federal University of Ceara. Nine samples of electronic tensiometers and three conventional mercury tensiometers were tested for a month period of data gathered at a 2 Hz frequency. The monitoring made it possible to produce insights on the soil drying process, on the effect of temperature fluctuation on the readings, and it was possible to evaluate the response time and sensitivity of the electronic tensiometer. It was found that the temperature effect on the readings increases as the matrix potential decreases, thus it is essential to install temperature sensors on the electronic tensiometers in order to remove the errors induced by temperature variation especially if the sensors are to be used at the peak hours. The response time increases as the matrix potential decreases and the tensiometers tested presented average sensitivity of 42.833 mV(kPa)-1, and precision of 0.02334 kPa or 0.2380 cm c H2O.
pressure sensor; response time; sensitivity
