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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #279865

Title: Closed depression topography and Harps soil, revisited

item Logsdon, Sally
item James, David

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/24/2012
Publication Date: 7/1/2012
Citation: Logsdon, S.D., James, D.E. 2012. Closed depression topography and Harps soil, revisited. ASA-CSSA-SSSA Annual Meeting Abstracts. Available:

Interpretive Summary:

Technical Abstract: The Harps soil (Fine-loamy, mixed superactive, mesic Typic Calciaquoll) developed around wetland depressions. The purpose of this study is 1) to delineate surface deposition of carbonates representing Harps soil which results from outward and upward flow around closed depressions, and 2) to relate the carbonate deposits to soil landscape features. The study was based on field-measured soil surface carbonates determined by violent effervescence with 10% HCl. GIS and associated programing was used to determine landscape features and depression depth. The newly mapped carbonate zones and the Harps map units partly overlapped; one third of the original Harps map units were included in the newly mapped carbonate areas but over half of the newly mapped carbonate areas were outside the original Harps map units. The carbonate areas were located primarily in the edges of and just outside the depressions with only 4% more than 0.5 m deep in the depression. The carbonate areas were on flatter areas (mean slope of 1.14% compared with median slope of 1.94% for the whole area), and somewhat more convex profile curvatures (-0.25 / 100m compared with -0.12 / 100m for the whole area), especially close to the depressions. Even with tile drainage, the depressions still held water following snow melt and intense rain often for a few days or even weeks. This might have been long enough to continue the outward and upward water flow and carbonate transport pattern.