Characterization of a new heat dissipation matric potential sensor.
Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare sensor it is possible to measure the matric potential indirectly to monitor or control irrigation. This sensor is based on thermal properties of a synthetic felt. After a defined heating phase the cooling time to a threshold temperature is a function of the water content in the synthetic felt. The water content in this porous matrix is controlled by the matric potential in the surrounding soil. Calibration measurements have shown that  the sensor is most sensitive to -400 hPa and allows lower sensitivity measurements to -800 hPa. The disturbing effect of the temperature change during the measurement on the cooling time can be corrected by a linear function and the differences among sensors are minimized by a two point calibration.
Institute of Natural Resources Sciences, Zurich University of Applied Sciences, CH-8820 Wädenswil, Switzerland. luzius.matile@zhaw.ch
Luzius
L
Matile
Roman
R
Berger
Daniel
D
Wächter
Rolf
R
Krebs
D057914:Agricultural Irrigation / Q000295:instrumentation*; D002138:Calibration; D006358:Hot Temperature; D012815:Signal Processing, Computer-Assisted; D012987:Soil; D013997:Time Factors
D012987:Soil