IN SITU HYDRAULIC CONDUCTIVITY OF A FRAGIPAN SOIL IN THE SOUTHERN COASTAL PLAINS1

Abstract

More than 250,000 ha of soils having a fragipan or fragic properties occur in the Southern Coastal Plains Soil Province. These soils have moderate to severe land use restrictions, partially due to perched water, slow permeability, and restricted root growth. The Cowarts soil (Fragic Paleudults; fine-loamy, siliceous, thermic family), which is developed from marine sediments, was selected to determine in situ hydraulic conductivities and related hydrological properties. The moderately well-expressed fragipan has higher bulk density, less pore space, smaller pores, less available water, and lower hydraulic conductivity values than horizons above or below the pan. With an increase in hydraulic head, an increase in hydraulic conductivity was less in the fragipan than in associated horizons. More than 250,000 ha of soils having a fragipan or fragic properties occur in the Southern Coastal Plains Soil Province. These soils have moderate to severe land use restrictions, partially due to perched water, slow permeability, and restricted root growth. The Cowarts soil (Fragic Paleudults; fine-loamy, siliceous, thermic family), which is developed from marine sediments, was selected to determine in situ hydraulic conductivities and related hydrological properties. The moderately well-expressed fragipan has higher bulk density, less pore space, smaller pores, less available water, and lower hydraulic conductivity values than horizons above or below the pan. With an increase in hydraulic head, an increase in hydraulic conductivity was less in the fragipan than in associated horizons. © Williams & Wilkins 1978. All Rights Reserved.