Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 3, 2004
Publication Date: May 3, 2004
Citation: Flerchinger, G.N., Seyfried, M.S., and Hardegree, S.P., 2004. Use of the soil freezing characteristic to model frozen and unfrozen soil water dynamics. In: Annual meetings abstracts (CD-ROM), ASA, CSA, and SSSA, Madison, WI. Vol 49, pp. 6418 (CD-ROM abstract) Technical Abstract: The soil moisture characteristic is critical to accurately simulate soil water dynamics but is difficult to measure, particularly for the dry regions of the curve. The relation between freezing soil temperatures, soil water potential and liquid water content, termed the soil freezing characteristic, is controlled by the soil moisture characteristic curve. Simultaneous measurement of soil temperature and liquid water content under frozen conditions enables in situ estimation of the soil moisture characteristic curve through its similarity to the soil freezing characteristic. Measured moisture characteristic curves for the three soil types at the Orchard Field Test Site in southwest Idaho agreed well with measured soil freezing characteristics. The methodology was tested on a rangeland site on the Boise Front. Simulations of soil water content for the Boise Front using the estimated soil moisture characteristic agreed well with measurements under both winter and summer conditions. Results suggest that the soil freezing characteristic may be used to estimate the moisture release curve when soil temperature and liquid water content sensors are col-located and measured simultaneously. This methodology is particularly effective for the drier portion of the soil moisture characteristic, which is problematic to measure by conventional means.