CHARACTERISTICS OF COMPOSTS: MOISTURE HOLDING AND WATER QUALITY IMPROVEMENT

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 compost. 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 after the equivalent of one year of rainfall was applied to CMTs and ECCs. 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). The peak runoff rate decreased at lower slopes for the CMTs and ECCs with the onset of runoff at a 3:1 slope delayed by 15 minutes or more.

Language

  • English

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 160 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00987604
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-04/0-4403-2,, Research Report 0-4403-2
  • Contract Numbers: 0-4403
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Mar 2 2005 12:00AM