Wetting of agricultural soil measured by a simplified capillary rise technique

A - Papers appearing in refereed journals

Matthews, G. P., Watts, C. W., Powlson, D. S., Price, J. C. and Whalley, W. R. 2008. Wetting of agricultural soil measured by a simplified capillary rise technique. European Journal of Soil Science. 59 (4), pp. 817-823.

AuthorsMatthews, G. P., Watts, C. W., Powlson, D. S., Price, J. C. and Whalley, W. R.
Abstract

We describe the use of a capillary rise method to measure the wettability of 10 samples of agricultural soil from Rothamsted long-term experimental sites. The samples have very similar clay contents, but organic carbon (C) contents range from 11.5 to 31.2 g kg(-1). Their wetting rates were interpreted by an improved method of data analysis, consistent with the Washburn equation, and showed an increase in the effective contact angle between the water meniscus and the soil with increasing C content. This corresponds to a decrease in wettability with increasing C content, and accords with other results reported in the literature. By contrast with water, we found that capillary rise for n-hexane into soil did not depend on the soil's bulk density or C content. A priori calculations of the expected wetting rates from fluid properties and an effective hydraulic radius estimated by other methods gave magnitudes and trends that agreed with our experimental data. The results show that estimates of effective hydraulic radius can provide a useful approximation for characterizing soil wetting, but that further modelling should be carried out.

KeywordsSoil Science
Year of Publication2008
JournalEuropean Journal of Soil Science
Journal citation59 (4), pp. 817-823
Digital Object Identifier (DOI)doi:10.1111/j.1365-2389.2008.01039.x
Open accessPublished as non-open access
Funder project or codeSEF
ISSN13510754
1351-0754
PublisherWiley

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