Soil water retention curve of agrogray soils: Influence of anisotropy and the scaling factor

• Published in: Eurasian soil science Vol. 47; no. 12; pp. 1238 - 1244
• Main Authors: Umarova, A. B, Shein, E. V, Kukharuk, N. S
• Format: Journal Article
• Language: English
• Published: Moscow Springer-Verlag 01.12.2014; Pleiades Publishing; Springer; Springer Nature B.V
• Subjects: Analysis; Anisotropy; Decomposing organic matter; Earth and Environmental Science; Earth Sciences; equations; Forest soils; Geotechnical Engineering & Applied Earth Sciences; Humus; Moisture content; Retention; Soil horizons; Soil moisture; Soil Physics; Soil profiles; Soil properties; soil sampling; Soil water; soil water characteristic; Soils; Spring water; Statistical analysis; water; Water resources management; anisotropy in the soil properties; modeling; soil monoliths; sampling; water retention curve; asymmetry; loose soil samples
• ISSN: 1064-2293; 1556-195X
• DOI: 10.1134/S1064229314120096

The soil water characteristic or soil water retention curve (WRC) of medium-loamy gray forest soil horizons was studied in cylinder-shaped samples of disturbed and undisturbed structure. The sample height varied within 2–4 cm and the diameter within 4.5–10 cm. The soil monoliths were sampled in three profiles: vertically, along the slope, and across the slope in accordance with the intrasoil paleorelief formed by the funnel-shaped surface of the second humus horizon. The experimental WRC were approximated with the van Genuchten equation. The statistical analysis of the WRc approximation parameters proved to differ significantly in filled soil samples and monoliths, and a number of parameters differ for samples of the maximal height and diameter. The reliable differences of the parameters were also noted for the different sampling directions, most often, for those across the paleorelief slope. The noted variation in the WRC approximation parameters may substantially influence the predictive estimation of the spring water reserve for example. This fact suggests the necessity to strictly indicate the sampling procedure, in particular, with respect to the soil profile, the asymmetry in the soil properties, and the sample sizes (scaling factor) used for analyzing the hydrological properties of structured soils.