Wednesday, September 18, 2019
Hydric Soils as a Part of Water Treatment in Wetland Systems Essay
Hydric Soils as a Part of Water Treatment in Wetland Systems Most basically, a hydric soil is defined as "A soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part (Kent, 1994, p. 26)." Included by this definition in the United States Department of Agriculture/Soil Conservation Service's list Hydric Soils of the United States are all of the poorly drained and very poorly drained soils and most of the somewhat poorly drained soil series. Hydric soils are further categorized into two major groups: mineral soils and organic soils. Histosols (organic soils) typically contain at least 46 cm of organic matter in the upper part of the soil profile. They are grouped by the degree to which plant material and fibers are decomposed. Most decayed are the saprists (muck), followed by hemists (mucky-peats and peaty mucks), and fibrists (peats), the least decomposed. (Folists, the fourth group of organic soils, are not regarded as hydric soils because the organic part is not inundation or saturation derived.) Mineral soils ordinarily have less organic matter in the upper part of the soil profile than histosols. To be considered hydric soil, a mineral soil must meet specific drainage and water table criteria that indicate at least 15 consecutive days of saturation or 7 days of inundation during the growing season. Hydric mineral soils include soils in the Aquic subgroups, Aquic suborders, Albolls suborder, Salorthids great groups and Pell great groups of vertisols (Kent, 1994). In the field, hydric soils are distinguished by indicators displayed within the root zone. These include histosols, histic epipedons, high organic matter content in the surface hori... ...aton, C. K. Smoley, 216 p. Kadlec, Robert H., and Robert L. Knight, 1996, Treatment Wetlands: Boca Raton, Lewis Publishers, 893 p. Kent, Donald M., editor, 1994, Applied Wetlands Science and Technology: Boca Raton, Lewis Publishers, 436 p. Landers, Judith C., and Barbara A. Knuth, 1991, Use of Wetlands for Water Quality Improvement under the USEPA Region V Clean Lakes Program: Environmental Management, Vol. 15, No. 2, pp. 151-162. Mitsch, William J., and Gosselink, James G., 1993, Wetlands, Second Edition: New York, Van Nostrand Reinhold, 722 p. Simmons, Robert C., Arthur J. Gold, and Peter M. Groffman, 1992, Nitrate Dynamics in Riparian Forests: Groundwater Studies: Journal of Environmental Quality, Vol. 21, pp. 659-665. Singer, Michael J., and Donald N. Munns, 1996, Soils: An Introduction, Third Edition: Upper Saddle River, Prentice Hall, 480 p.