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Measuring Soil Matric Potential in situ by Sensing Heat Dissipation within a Porous Body: II. Experimental Results
Author(s) -
Phene C. J.,
Rawlins S. L.,
Hoffman G. J.
Publication year - 1971
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1971.03615995003500020018x
Subject(s) - water potential , bar (unit) , soil science , environmental science , porosity , soil water , water content , dissipation , geotechnical engineering , meteorology , thermodynamics , engineering , physics
A sensor described previously to measure the matric potential of soil water in situ was tested in soil‐plant systems. Experiments were performed in the laboratory in a controlled environment and in the field. In the field, temperatures obtained by the sensor were used to predict optimum time for measurement to avoid error caused by diurnal temperature drift in the soil. The error caused by temperature drift was eliminated completely by using two matched diode sensors and taking a temperature difference measurement. The accuracy of the matric potential sensor proved to be as good as or better than that of other techniques used to measure matric potential. Sensors with high sensitivity in the 0 to −2 bar matric potential range had an accuracy of ±0.2 bar. The accuracy decreased progressively to ±1 bar at a matric potential of −10 bars.