Abstracts

Assessing a Novel Method for Verifying Automated Oxidation-Reduction Potential Data Loggers: Laboratory and Field Tests

Author(s): Shoemaker, C.; Kröger, R.; Pierce, S.

Redox potential (Eh) describes the electrical pressure of systems. In waterlogged soils, Eh is an important parameter for regulating the products of biogeochemical cycling. Until recently, Eh was measured at individual points using an electrode attached to a voltmeter. This method can overlook dynamic diel and short term fluxes in the environment. Automated data loggers enable long-term continuous monitoring of Eh in soils; however, no protocol has been developed for testing the accuracy and precision of these loggers. Automated data loggers were tested under a laboratory with known voltages to assess the ability of these units to record Eh precisely and accurately. Voltages of +450 and -450 mV were applied to four loggers with four Eh sensors five times at +450 and -450 mV for each sensor, totaling 40 tests for each board. The average measured voltages varied from each other a maximum of ±8.25 mV and with a maximum range of ±23 mV. The voltage averages of all boards were accurate to ±17.85 mV with a maximum range of ±26 mV. These results indicate that measurements obtained by automated data loggers can be accurate to within a maximum of ±26 mV of the true value. Since soil Eh has a range of over 1000 mV, continuous automated data loggers can be a powerful tool in describing Eh fluxes in waterlogged systems. Additionally, field data obtained from the automated data loggers placed in vegetated and non-vegetated control plots were able to record vegetative diel Eh fluxes over a period of 48 hours. Significant spatial heterogeneity and vegetative influences were observed in Eh values. The loggers thus have the possibility to be used to monitor Eh responses to various management practices and environmental factors.
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1 Best Management Practices #1
2 Delta Water Assessment
3 Flood Assessment & Mgmt.
4 Wetlands
5 Watershed Mgmt. #1
6 Non-Point Source Assessment
7 Modeling
8 Water Quality
9 Best Mgt. Practices #2
10 Delta Water Conservation
11 Sedimentation
12 Storm Water
13 Watershed Mgt. #2
14 Public Water Systems
15 Surface Water Assessment & Evaluation

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