Abstract
There is increasing interest toward in situ solution monitoring of soil chemicals for agricultural, industrial, and ecological purposes. Rather than extracting soil solution, a series of laboratory experiments was conducted to evaluate a diffusion equilibration technique, providing for real time in situ soil solution nitrate concentration via UV absorption spectroscopy. Experiments allowed for diffusion of nitrate from an outside reservoir into a porous cup. The experimental data were compared with model predictions using three different analytical solutions: (i) an exact solution (EX model) assuming radial symmetry that includes a porous cup with a porous wall and a finite size outside reservoir, (ii) an approximate solution (RC model) that assumes an infinitely large supply reservoir with a porous cup wall that does not influence ion diffusion, and (iii) and a model based on an electric circuit analog (ECA model). The results indicate that the ECA solution provides the best match overall to the experimental data.
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Acknowledgements
This work was supported by the National Science Foundation Biocomplexity program by the funded proposal 0410055—Development ofMulti-Functional Heat Pulse Probe for Ecological and Soil Hydrological Monitoring of Plant Root Zones.
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Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Shaw, B.D., Tuli, A., Wei, JB. et al. Analytical Modeling of Soil Solution Monitoring by Diffusion in Porous Cups. Transp Porous Med 81, 341–360 (2010). https://doi.org/10.1007/s11242-009-9404-3
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DOI: https://doi.org/10.1007/s11242-009-9404-3