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United States Department of Agriculture

Agricultural Research Service

Title: Laboratory Calibration and Evaluation of Multisensor Capacitance Soil Waterprobes

Authors
item Baumhardt, Roland
item Lascano, R - TX AGRIC EXP STN, LUBBOCK
item Evett, Steven

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 1998
Publication Date: N/A

Technical Abstract: An alternative for gravimetric or nuclear soil water measurements is the use of capacitance probes. Our objective was to calibrate and verify the accuracy of soil water measurements using a multisensor capacitance probe (MCAP) in two soil materials with two water salinities under laboratory conditions. Disturbed surface and calcic layers of Olton soil (fine, mixed, superactive, thermic Aridic Paleustolls) were packed into triplicate, 0.5-m tall, 100-L columns and wetted. Soil water contents determined gravimetrically and by time domain reflectometry (TDR) at depths of 50, 150, 250, 350, and 450 mm were compared to those made with MCAPs installed at 100, 200, 300, and 400 mm below the surface. The MCAPs were initially calibrated using recommended air and water bath readings. Diurnal soil temperature change affected MCAP and TDR measurements, but soil and water properties only affected measurements by MCAPs. Using MCAPs sto measure soil water requires calibration and adjustment for soil temperature, soil properties, and water salinity.

Last Modified: 7/30/2014
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