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Characteristics of Composts: Moisture Holding and Water Quality Improvementby Christine J. Kirchoff, M.S., P.E., Dr. Joseph F. Malina, Jr., P.E., D.E.E., Dr. Michael E. Barrett, P.E. ABSTRACT The objective of this study was investigation of the potential beneficial use of compost manufactured topsoil in highway rights-of-way in Texas. The water holding capacity and the physical, chemical and microbiological characteristics of composted manures (dairy cattle, poultry litter, and feedlot), composted biosolids and sandy and clay soil; compost manufacture topsoil (CMT) that contained composted manures or composted biosolids mixed with either sandy soil or clay soil; as well as erosion control compost (ECC) that contained compost and wood chips were evaluated. The characteristics of the leachate produced during “first-flush” and “long-term” column studies were determined. The onset of runoff and peak rate of runoff from CMT and ECC were monitored in channel studies at slopes of 2:1, 3:1, 5:1, and 8:1. The porosity of the sandy soil increased and the bulk density decreased with the addition of caompost. Composted feedlot manure was the only compost that exhibited phytotoxic effects for both salt tolerant and salt intolerant plant test seedlings. Therefore, composted feedlot manure should be used with caution along highway rights-of-way due to possible phytotoxicity. Observations during the extended column studies indicate decrease in the concentrations of nitrate, total nitrogen, phosphorus, copper, zinc and total dissolved solids the after the equivalent of one-year of rainfall was applied to CMT’s and ECC’s . The concentrations observed in the laboratory are high compared to concentrations of constituents in water passing through the CMT in the field which infiltrates into the supporting soil where the constituents are taken up by plants and/or undergo chemical and biological transformations resulting in lower concentrations entering surface and ground water sources. The highest peak runoff occurred at the steepest slope (2:1) slope. The peak runoff rate decreased at lower slopes for the CMT’s and ECC’s with the onset of runoff at a 3:1 slope delayed by 15 minutes or more. The highlighted links that follow are connected to Adobe pdf files of the corresponding material. To view them you must have the Adobe Acrobat Reader 3.0. View the Report...(3125 KB)
These materials may be used for study, research, and education, but please credit the authors and the Center for Research in Water Resources, The University of Texas at Austin. All commercial rights reserved. Copyright 2002 Center for Research in Water Resources. |
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