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Comment on “Comparison of Three Methods to Calibrate TDR for Monitoring Solute Movement in Undisturbed Soil”
Author(s) -
Nadler Arie
Publication year - 1998
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/sssaj1998.03615995006200020029x
Subject(s) - christian ministry , hebrew , public work , citation , library science , environmental science , hydrology (agriculture) , computer science , political science , history , geology , public administration , law , geotechnical engineering , classics
Today time domain reflectometry (TDR) is probably the only technology that enables simultaneous measurement of both water content and solute concentration distribution in a wide range of soil moisture and textures. Hundreds of users routinely apply TDR for dozens of purposes related to hydrology, engineering, environmental issues, construction, industry, and even for road maintenance (O'Connor et al., 1994). Mallants et al. (1996) skillfully presented and compared three methods to calibrate TDR for monitoring soil solute content: (1) the application of a solute pulse long enough for the concentration in the soil to become equal to the input concentration; (2) a numerical integration of the observed response to a tracer pulse input function; and (3) determination of the soil impedance (Z0) using an independently measured relationship between Z0 and the solute concentration. However, when Mallants et al. (1996, Fig. 9) compared Z0 estimated by Method 3 to the observed Z0 (either by Method 1 or 2), they found a systematic discrepancy. The following comments are aimed strictly toward clarifying two aspects of Method 3 calculations that may improve monitoring salt movement in the laboratory and in the soil profile. Rearranging Eq. [7] Mallants et al. (1996) and substituting 1/78, where 0 is soil water content, with F results in