Distinguishing between red-clay soils that are non-expansive and can reduce and red-clay soils developing in problematic red parent material, which are expansive, but also non-reducing, is key for proper on-site wastewater system placement. The Arkansas Department of Health allows for the placement of on-site wastewater systems in certain red-clay soils that have the potential to reduce, but only in the Ozark Highlands [Major Land Resource Area (MLRA) 116A], which is referred to as the red-soil exception. There is currently little scientific data to support the geographic restriction of the red-soil exception. The objectives of this study were to: i) confirm the non-expansiveness and reducibility of select soils in the Ozark Highlands that meet the criteria for the red-soil exception for determining soil suitability for on-site wastewater system placement, and ii) compare the expansiveness and reducibility of the residual and colluvial, red-clay soils of the Ozark Highlands to those in other MLRA region groupings in Arkansas. Fresh soil samples were collected in conjunction with archived soil samples to create a 50-sample data set from the 38- to 50-cm soil depth interval for analyses. The alluvial soils of the Red and Arkansas Rivers region, which are known to be expansive and non-reducing, had a mean coefficient of linear extensibility (COLE) of 0.116 mm mm-1, whereas soils from the other four MLRA regions evaluated, including the Ozark Highlands, had significantly lower (P < 0.01) COLE values. Based on a 1-hr reduction test, soils from the Red and Arkansas Rivers region changed red color the least (∆A of -8.6 in the LAB color scheme; P < 0.01) compared to soil from all four other MLRA regions evaluated, including the Ozark Highlands. As an often-used indicator of expansiveness, the Mehlich-3-estimated cation exchange capacity (CEC-M), excluding any contribution from soil organic matter, was larger (24.5 cmolc kg-1; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions evaluated. The CEC-M:clay ratio was also larger (0.46; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions, which did not differ. Results of this study indicate the red-soil exception, used by the Arkansas Department of Health for determining on-site wastewater system suitability, could be expanded to include several additional MLRAs in Arkansas, excluding the alluvial, red-clay soils of the Arkansas and Red River valleys due to their expansive and reduction-resistant characteristics.
","abstract_html":"<p>Distinguishing between red-clay soils that are non-expansive and can reduce and red-clay soils developing in problematic red parent material, which are expansive, but also non-reducing, is key for proper on-site wastewater system placement. The Arkansas Department of Health allows for the placement of on-site wastewater systems in certain red-clay soils that have the potential to reduce, but only in the Ozark Highlands [Major Land Resource Area (MLRA) 116A], which is referred to as the red-soil exception. There is currently little scientific data to support the geographic restriction of the red-soil exception. The objectives of this study were to: i) confirm the non-expansiveness and reducibility of select soils in the Ozark Highlands that meet the criteria for the red-soil exception for determining soil suitability for on-site wastewater system placement, and ii) compare the expansiveness and reducibility of the residual and colluvial, red-clay soils of the Ozark Highlands to those in other MLRA region groupings in Arkansas. Fresh soil samples were collected in conjunction with archived soil samples to create a 50-sample data set from the 38- to 50-cm soil depth interval for analyses. The alluvial soils of the Red and Arkansas Rivers region, which are known to be expansive and non-reducing, had a mean coefficient of linear extensibility (COLE) of 0.116 mm mm-1, whereas soils from the other four MLRA regions evaluated, including the Ozark Highlands, had significantly lower (P < 0.01) COLE values. Based on a 1-hr reduction test, soils from the Red and Arkansas Rivers region changed red color the least (∆A of -8.6 in the LAB color scheme; P < 0.01) compared to soil from all four other MLRA regions evaluated, including the Ozark Highlands. As an often-used indicator of expansiveness, the Mehlich-3-estimated cation exchange capacity (CEC-M), excluding any contribution from soil organic matter, was larger (24.5 cmolc kg-1; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions evaluated. The CEC-M:clay ratio was also larger (0.46; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions, which did not differ. Results of this study indicate the red-soil exception, used by the Arkansas Department of Health for determining on-site wastewater system suitability, could be expanded to include several additional MLRAs in Arkansas, excluding the alluvial, red-clay soils of the Arkansas and Red River valleys due to their expansive and reduction-resistant characteristics. </p>","abstract_has_math":false,"creators":["Darnell, Bailey"],"institution":null,"degree_name":"Master of Science in Crop, Soil & Environmental Sciences (MS)","degree_level":"Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["West, Larry T.","Wood, Lisa S."],"advisors":["Brye, Kristofor R."],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-05-01T07:00:00Z","date_published":"2021-05-01T07:00:00Z","updated_at":"2026-07-24T00:59:32Z","subjects":["Arkansas","Expansive","Hydrology","Ozark Highlands","Red-Soil Exception","Rural","Soil","Wastewater","Environmental Sciences","Fresh Water Studies","Soil Science","Water Resource Management"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarworks.uark.edu/etd/4102","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["West, Larry T.","Wood, Lisa S."]},{"key":"dc:contributor.advisor","label":"Advisor","values":["Brye, Kristofor R."]},{"key":"dc:creator","label":"Author","values":["Darnell, Bailey"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2021"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2024-02-06T08:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Crop, Soil & Environmental Sciences (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Arkansas","Expansive","Hydrology","Ozark Highlands","Red-Soil Exception","Rural","Soil","Wastewater","Environmental Sciences","Fresh Water Studies","Soil Science","Water Resource Management"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarworks.uark.edu/etd/4102"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Distinguishing between red-clay soils that are non-expansive and can reduce and red-clay soils developing in problematic red parent material, which are expansive, but also non-reducing, is key for proper on-site wastewater system placement. The Arkansas Department of Health allows for the placement of on-site wastewater systems in certain red-clay soils that have the potential to reduce, but only in the Ozark Highlands [Major Land Resource Area (MLRA) 116A], which is referred to as the red-soil exception. There is currently little scientific data to support the geographic restriction of the red-soil exception. The objectives of this study were to: i) confirm the non-expansiveness and reducibility of select soils in the Ozark Highlands that meet the criteria for the red-soil exception for determining soil suitability for on-site wastewater system placement, and ii) compare the expansiveness and reducibility of the residual and colluvial, red-clay soils of the Ozark Highlands to those in other MLRA region groupings in Arkansas. Fresh soil samples were collected in conjunction with archived soil samples to create a 50-sample data set from the 38- to 50-cm soil depth interval for analyses. The alluvial soils of the Red and Arkansas Rivers region, which are known to be expansive and non-reducing, had a mean coefficient of linear extensibility (COLE) of 0.116 mm mm-1, whereas soils from the other four MLRA regions evaluated, including the Ozark Highlands, had significantly lower (P < 0.01) COLE values. Based on a 1-hr reduction test, soils from the Red and Arkansas Rivers region changed red color the least (∆A of -8.6 in the LAB color scheme; P < 0.01) compared to soil from all four other MLRA regions evaluated, including the Ozark Highlands. As an often-used indicator of expansiveness, the Mehlich-3-estimated cation exchange capacity (CEC-M), excluding any contribution from soil organic matter, was larger (24.5 cmolc kg-1; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions evaluated. The CEC-M:clay ratio was also larger (0.46; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions, which did not differ. Results of this study indicate the red-soil exception, used by the Arkansas Department of Health for determining on-site wastewater system suitability, could be expanded to include several additional MLRAs in Arkansas, excluding the alluvial, red-clay soils of the Arkansas and Red River valleys due to their expansive and reduction-resistant characteristics.
"]},{"key":"dc:title","label":"Title","values":["Characterization of Problematic Red Clay Soils in Arkansas for the Purpose of Onsite Wastewater System Placement"]}]}],"canonical_facts":{"dc:contributor":["West, Larry T.","Wood, Lisa S."],"dc:contributor.advisor":["Brye, Kristofor R."],"dc:creator":["Darnell, Bailey"],"dc:date":["2021"],"dc:date.available":["2024-02-06T08:00:00Z"],"dc:description.abstract":["Distinguishing between red-clay soils that are non-expansive and can reduce and red-clay soils developing in problematic red parent material, which are expansive, but also non-reducing, is key for proper on-site wastewater system placement. The Arkansas Department of Health allows for the placement of on-site wastewater systems in certain red-clay soils that have the potential to reduce, but only in the Ozark Highlands [Major Land Resource Area (MLRA) 116A], which is referred to as the red-soil exception. There is currently little scientific data to support the geographic restriction of the red-soil exception. The objectives of this study were to: i) confirm the non-expansiveness and reducibility of select soils in the Ozark Highlands that meet the criteria for the red-soil exception for determining soil suitability for on-site wastewater system placement, and ii) compare the expansiveness and reducibility of the residual and colluvial, red-clay soils of the Ozark Highlands to those in other MLRA region groupings in Arkansas. Fresh soil samples were collected in conjunction with archived soil samples to create a 50-sample data set from the 38- to 50-cm soil depth interval for analyses. The alluvial soils of the Red and Arkansas Rivers region, which are known to be expansive and non-reducing, had a mean coefficient of linear extensibility (COLE) of 0.116 mm mm-1, whereas soils from the other four MLRA regions evaluated, including the Ozark Highlands, had significantly lower (P < 0.01) COLE values. Based on a 1-hr reduction test, soils from the Red and Arkansas Rivers region changed red color the least (∆A of -8.6 in the LAB color scheme; P < 0.01) compared to soil from all four other MLRA regions evaluated, including the Ozark Highlands. As an often-used indicator of expansiveness, the Mehlich-3-estimated cation exchange capacity (CEC-M), excluding any contribution from soil organic matter, was larger (24.5 cmolc kg-1; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions evaluated. The CEC-M:clay ratio was also larger (0.46; P < 0.01) for soils from the Red and Arkansas Rivers region than for soils from all four other regions, which did not differ. Results of this study indicate the red-soil exception, used by the Arkansas Department of Health for determining on-site wastewater system suitability, could be expanded to include several additional MLRAs in Arkansas, excluding the alluvial, red-clay soils of the Arkansas and Red River valleys due to their expansive and reduction-resistant characteristics.
"],"dc:identifier":["https://scholarworks.uark.edu/etd/4102"],"dc:subject":["Arkansas","Expansive","Hydrology","Ozark Highlands","Red-Soil Exception","Rural","Soil","Wastewater","Environmental Sciences","Fresh Water Studies","Soil Science","Water Resource Management"],"dc:title":["Characterization of Problematic Red Clay Soils in Arkansas for the Purpose of Onsite Wastewater System Placement"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science in Crop, Soil & Environmental Sciences (MS)"]},"updated_at":"2026-07-24T00:59:32Z"}