Significance of Stability-Maturity Testing and Plant Bioassays to Assess Composts for Inclusion in Soil Building Projects

Woods End Laboratories, Inc., 2012

Summary Excerpt: There is increasing demand for recycled organic matter composts in applications such as organic potting mixes, restoration of disturbed soils, and constructed soil ecosystems. There are different compost quality standards applied by the scientific community, by government and the industry. Understanding and accepting relevant maturity and stability standards is imperative. If inappropriate compost tests are applied to these important areas, it may be harmful and could set back the burgeoning interest. Examples described in this report are guidelines for "stability and maturity" and "plant maturity bioassays"; the issue of the high nutrient density of compost is not addressed. In the USA, "stability" protocols stem from early debates within the sludge/compost industry. In several cases, measurement units for test thresholds are scientifically obscure and it is questionable if protocols have been calibrated for end-uses. To meet this challenge for sustainable soil management, amended soils must be approached as a unit volume - the plant root environment. Properties that organic amendments bestow on a whole environment must be accurately predicted. 

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Landscape Architecture/Design Specifications for Compost Use, June 2005

  • Turf Establishment with Compost
  • Planting Bed Establishment with Compost
  • Compost as a Landscape Backfill Mix Component
  • Compost as a Landscape Mulch
  • Compost as a Soil Blanket for Erosion Control
  • Compost as a Filter Berm for Sediment Control
  • Includes Seal of Testing Assurance Language

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