Distribution and Properties of Vesicular Horizons in the Western United States

Abstract

Vesicular horizons are thin (usually <10 cm) surface or near‐surface horizons characterized by the predominance of vesicular porosity. They are widespread in arid and semiarid lands, occurring on every continent and covering 156,000 km2 of the western United States. Vesicular horizons have critical implications for management due to their role in controlling surface hydrology and dust mobilization. This study evaluates the distribution and variation in expression of vesicular horizons across the western United States using the soil databases available from the USDA. A vesicular horizon index (VHI) that incorporates vesicular horizon thickness and the size and quantity of vesicular pores was developed using soil descriptions from a published chronosequence study. The VHI was applied to descriptions from the soil survey databases to evaluate vesicular horizon expression across the western United States. Vesicular horizons were better expressed (higher VHI) in the Central and Northern Basin and Range compared to the Mojave and Sonoran Basin and Range. This may be due to differences in temperature regime or to larger areas of playas in the Central and Northern Basin and Range that serve as sources of dust that forms the parent material for vesicular horizons. The median VHI was highest in the Aridisols and Mollisols compared to other soil orders. No significant relationship was found between VHI and soil textures. Vesicular horizons are widely distributed in western United States and occur across a wide range of soil types and soil‐forming environments.

Biological Soil Crusts in the Mojave Desert, USA: Micromorphology and Pedogenesis

“…The Av terminology used here was first presented by Springer (1958) to describe fine-grained surface soil horizons containing vesicular porosity (see also McFadden et al, 1987;Turk and Graham 2011). Under suitable conditions, BSC succession proceeds from cyanobacteria crusts to tall moss-lichen pinnacled crusts overlying mineral Av horizons (Fig.…”

“…Vesicular pores are a defining feature of Av soil horizons (Turk and Graham, 2011). These horizons are known to form in environments where eolian materials are added to the surface and a surficial seal or some other condition traps air (Evenari et al, 1974;Bunting, 1977).…”

Two Microenvironments at the Soil Surface of Saline Wetlands in Monegros, Spain

“…On the other hand, due to the soil moisture of A2 (up to 33%), the summer temperature (21.6-35.7°C) produces an intense evaporation of the interstitial saline water. This evaporation is addressed to the cracks of the A1v because of the mulching effect of the vesicular porosity of A1v layer, whose role in the control of the surface hydrology has been stressed by Turk and Graham (2011). In the studied playa-lakes, the saline water table feeds the capillary ascent throughout the A2 horizon even in dry periods.…”

“…1d). Turk and Graham (2011) described the vesicular horizon as "a common feature of soils in arid and semiarid lands" and stressed its role in controlling the surface hydrology. Vesicular horizon, considered ubiquitous in undisturbed desert soils by McFadden et al (1998), was known years ago with different settings, for example, produced by repeated irrigations (Miller, 1971), or occurring under a laminated surface layer in saline areas (Joeckel and Clement, 1999), or as subpavement vesicular horizon in many deserts, better developed under clasts (Springer, 1958;Laity, 2011).…”

“…Vesicular horizon, considered ubiquitous in undisturbed desert soils by McFadden et al (1998), was known years ago with different settings, for example, produced by repeated irrigations (Miller, 1971), or occurring under a laminated surface layer in saline areas (Joeckel and Clement, 1999), or as subpavement vesicular horizon in many deserts, better developed under clasts (Springer, 1958;Laity, 2011). As reviewed by Turk and Graham (2011) the genesis of vesicular horizons have been frequently associated with rough soil surfaces or with stone pavements (Bouza et al, 1993), which is not the case in the Monegros playa-lakes where coarse fragments are rare. The vesicular horizon and the lack of stones also occur in other saline flats, as noted by Joeckel and Clement (1999) for eastern Nebraska, by Mees and Singer (2006) for the Aral Sea or by Buck et al (2011) for the Salton Sea in California.…”