Homolák, Marián and Pichler, Viliam and Jury, William A. and Capuliak, Jozef and O'Linger, JoAnn and Gregor, Juraj (2010) Unsaturated Hydraulic Conductivity Estimation of a Forest Soil Assuming a Stochastic-Convective Process. Soil Science Society of America Journal, 74 (1). pp. 292-300. ISSN 0361-5995 http://resolver.caltech.edu/CaltechAUTHORS:20100209-154412553
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Measurement of soil hydraulic conductivity requires considerable time and effort, which makes it difficult to characterize this important parameter across larger areas, especially remote forest regions. Forest soils are frequently texturally coarser than those in agricultural areas, making them more probable candidates for applications building on the stochastic-convective hypothesis. We developed a method for measuring unsaturated soil hydraulic conductivity based on the analysis of a dye tracer resident concentration profile. In the experiment, partially saturated, steady-state water flow was established in a forest allophanic soil by a sprinkler operating at 50 mm h^(–1), after which the water application was switched to a 10 mg L^(–1) Brilliant Blue FCF solution. The tracer was applied continuously until its cumulative infiltration reached 125 mm, after which the stained soil profile was exposed and photographed. The picture was subjected to an image analysis procedure designed to obtain the resident concentration profile of the tracer. The concentration was fitted to the solution of the convective lognormal transfer function, whose parameters were used in further calculations using functional relationships derived from the stochastic-convective framework. The resulting hydraulic conductivity as a function of soil water content agreed within an order of magnitude with the relationship obtained by the instantaneous profile method. While the Mualem–van Genuchten model better reproduced the shape of that relationship, it strongly underestimated the hydraulic conductivity across the soil water content interval of interest (0.1–0.4). Finally, ways to improve the predictive capacity of the stochastic-convective approach in terms of the general trends of the functional relationship were proposed.
|Additional Information:||© 2009 Soil Science Society of America. Received 22 May 2009. We thank Dr. V. Novák (Institute of Hydrology, Slovak Academy of Sciences, Bratislava) as well as Prof. C. Sławiński (Institute of Agrophysics, Polish Academy of Sciences, Lublin) for producing Mualem–van Genuchten K(θ) prediction and values obtained by the instantaneous profile method. This investigation was supported by scientific grants awarded by the Research and Development Agency APVV-0468-06 and the Scientific Grants Agency of the Ministry of Education and the Slovak Academy of Sciences no. 1/0703/08 and MVTS COST FP0601.|
|Official Citation:||Homolak, Marian, Pichler, Viliam, Jury, William A., Capuliak, Jozef, O'Linger, JoAnn, Gregor, Juraj Unsaturated Hydraulic Conductivity Estimation of a Forest Soil Assuming a Stochastic-Convective Process Soil Sci Soc Am J 2009 74: 292-300|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||10 Feb 2010 21:12|
|Last Modified:||26 Dec 2012 11:45|
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