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Response of a New Soil Water Sensor to Variable Soil, Water Content, and Temperature
Author(s) -
Seyfried M.S.,
Murdock M.D.
Publication year - 2001
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/sssaj2001.65128x
Subject(s) - soil water , water content , reflectometry , environmental science , soil science , soil type , calibration , soil classification , geology , time domain , geotechnical engineering , mathematics , statistics , computer science , computer vision
The success of time domain reflectometry (TDR) has led to the development of other instruments that use the soil dielectric constant as the basis for determining volumetric soil water content. An example is the Water Content Reflectometer (WCR; Campbell Scientific, Logan, UT), which is much less expensive than TDR and is used widely, although little has been published concerning its applicability to soil water content monitoring.1 The primary objectives of this study were to determine the WCR soil water calibration for different soils and to investigate how it is affected by changing temperature. We found the individual sensors to be very precise (CV ≤ 0.05) under the controlled laboratory conditions of this study. Variability among sensors, determined in air and ethanol, indicated significant( α = 0.05 )sensor differences that were largely accounted for with a simple additive correction. Sensor soil water calibration was investigated in four soils under varying water contents across a 40°C temperature range. We found that (i) soil water calibration was significantly( α = 0.05 )different for each soil tested, (ii) there was a significant( α = 0.05 )temperature response for all soils, and (iii) the effect of temperature varied with soil water content and soil type. Both the soil type and temperature sensitivities we observed were probably due to the relatively high electrical conductivity (EC) of the soils tested.