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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #82796
Title: CALIBRATION OF CS-615 (RPM) SOIL WATER SENSORS IN A SILT LOAM SOIL

Author
item Mutziger, Andrew
item Lentz, Rodrick
item Sojka, Robert

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Reflected-pulse multivibrator (RPM) soil water sensors (Campbell Scientific, Inc., model CS-615) employ TDR principles but do not require a cable tester for measurements. The calibration functions supplied with the sensors produced variable errors when applied to measurements in Portneuf silt loam soils (coarse-silty, mixed, mesic Durixerollic Calciorthid). The maximum deviation observed was from a measurement in soil with an actual volumetric water content of 0.47 yielded a calculated value of 0.96. The objective of this work was to calibrate the RPM sensors for field use. Calibration measurements were made in uniformly mixed and moistened soil that was hand packed (1.35 g cm(**3)) in PVC columns. The measurement variables were temperature, soil horizon, and volumetric water content. The soil specific calibration is presented as a function of temperature and bulk soil EC/pH of the saturation paste. A correction for inter-probe variation is also included.