Vertisol Crack Extent Associated with Gilgai and Soil Moisture in the Texas Gulf Coast Prairie

Abstract

Long‐term observations of in situ crack formation and closure in shrink‐swell soils are rare, but important to understanding hydrology in shrink‐swell soils. To analyze spatial and temporal variability of crack development in a Vertisol with gilgai, soil cracks were measured on a 100‐m2 area of Laewest clay (fine, smectitic, hyperthermic Typic Hapludert) with native tallgrass vegetation on 42 dates from 1989 to 1998. Our objectives were to (i) report the distribution of Vertisol cracking across gilgai microtopography; (ii) estimate crack depth as a function of crack width considering gilgai; (iii) investigate the relationship of surface cracking and soil moisture considering gilgai and hysteresis. All surface cracks were mapped on scaled diagrams with width categorized, and some crack depth measured. Gravimetric soil moisture corresponding to crack measurements was measured on 18 dates, and on an additional 32 dates without crack measurements. Drying, wetting, and uniform soil moisture conditions were classified from the difference in soil moisture from 10‐ to 25‐cm depths. Microtopography was quantified using a digital elevation model. Results showed that crack area density was greatest on microhighs and microslopes, though microlows had the largest cracking potential. The linear correlation between crack depth and width was moderately strong (r2 = 0.5), and not affected significantly by gilgai and hysteresis. However, taking hysteresis into account improved the linear regression models of crack area density versus soil moisture (up to r2 = 0.69) on both microhighs and microlows. Antecedent soil moisture seemed to impact in situ crack area density. Further field studies are recommended.

Desiccation cracks act as natural seed traps in flood-meadow systems

“…This result is in line with Tang et al (2008), who observed that cracks appeared in the same positions in consecutive drying cycles in a laboratory experiment. Kishne et al (2009), however, report that soil cracks in a prairie Vertisol along the Central Texas Gulf Coast sometimes closed and re-opened at exactly the same places, but shifted locations other times. This might also be the case in our study system (as indicated by sites A and E, cf.…”

“…Although there are several papers focusing on the mathematical description of crack patterns (e.g. Chertkov 2002;2005;Hallett and Newson 2005;Vogel et al 2005a;Vogel et al 2005b;Cornelis et al 2006), their potential spatial constancy has received surprisingly little attention so far (but see Tang et al 2008;Kishne et al 2009). Apparently, more research is needed to elucidate the trapping potential of desiccation cracks and the influence on seed bank formation.…”

Vertic properties and gilgai-related subsurface features in soils of south-western Poland

“…Clay accumulation in the argic horizon (up to 24-30%) made it more similar to the clayey materials susceptible for shrink-swell phenomena, in particular for cracking under summer drought (Johnson et al, 1987;Kishné et al, 2009). Such a soil series, where the development of a vertic horizon was able due to significant clay accumulation in Bt horizon were identified and explained by Smith (1986) in the southern states of the US.…”

Using Geographic Information Systems (GIS) to Inventory Coastal Prairie Wetlands Along the Upper Gulf Coast, Texas

“…Within this landscape lie pimple mounds, undrained depressions and segments of meandering and abandoned stream channels (Aronow 1986) with local microtopography of 1.5 to 3 m. The dominant soil types are Vertisols and Alfisols that developed over Pleistocene deposits. Kishné et al (2009) reported that most CPW soils are episaturated with a zone of unsaturated soils between the surface saturated soils and the unconfined groundwater table. Thus with the exception of coastal dune wetlands, most CPWs have little groundwater exchange.…”