The Potential Use of Soil Moisture Sensors for Observing Hydraulic Redistribution Characteristics

Xu Liang; Tyler W. Davis
A field study along a grass-covered hillside in south-western Pennsylvania revealed diel fluctuations in soil moisture measurements resembling hydraulically redistributed water. Further analysis of the measurements over a summer and winter season supports this finding. The observations are analyzed for possible influences due to soil temperature. Temperature influence on the EC-5 soil moisture sensor readings appears to be present at 5 cm in the form of a correlated pattern with temperature, i.e., an increase in soil moisture with temperature. An inversely correlated pattern, i.e., an increase in soil moisture during the nighttime, shown at 40 and 62 cm is present during the summer dry-down periods and absent during the wet winter season. Given the available data, it is likely that more than temperature is affecting the measurements. Significant amounts of water are found to be redistributed compared to amounts transpired (20–60%). Continued research on this subject is recommended.
Hydraulic Redistribution; Soil Moisture Observations; Soil Moisture Sensor Measurements
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