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| DOI: | 10.21273/HORTTECH.16.3.0471 |
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| Web URL(s): | https://journals.ashs.org/horttech/view/journals/horttech/16/3/article-p471.xml?rskey=0WXQFC
Last checked: 11/20/2019
Requires: PDF Reader |
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| Publication Type:
| Refereed |
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| Author(s): | Rowe, D. Bradley;
Monterusso, Michael A.;
Rugh, Clayton L. |
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| Author Affiliation: | Rowe: Associate Professor, Department of Horticulture; Rugh: Assistant Professor, Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan |
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| Title: | Assessment of heat-expanded slate and fertility requirements in green roof substrates |
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| Section: | Research reports
Other records with the "Research reports" Section
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| Source: | HortTechnology. Vol. 16, No. 3, July-September 2006, p. 471-477. |
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| Publishing Information: | Alexandria, VA: American Society for Horticultural Science |
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| # of Pages: | 7 |
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| Keywords: | TIC Keywords: Organic matter; Leaching; Roofscapes; Survival; Nitrogen; Phosphorus; Native vegetation; Sedum; Fertilizers; Water availability; Irrigation
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| Trade Names: | Permatill |
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| Abstract/Contents: | "Green roof technology in the United States is in the early development stage and several issues must be addressed before green roofs become more widespread in the U.S. Among these issues is the need to define growing substrates that are lightweight, permanent, and can sustain plant health without leaching nutrients that may harm the environment. High levels of substrate organic matter are not recommended because the organic matter will decompose, resulting in substrate shrinkage, and can leach nutrients such as nitrogen (N) and phosphorus (P) in the runoff. The same runoff problems can occur when fertilizer is applied. Also, in the midwestern U.S., there is a great deal of interest in utilizing native species and recreating natural prairies on rooftops. Since most of these native species are not succulents, it is not known if they can survive on shallow, extensive green roofs without irrigation. Five planting substrate compositions containing 60%, 70%, 80%, 90%, and 100% of heat-expanded slate (PermaTill) were used to evaluate the establishment, growth, and survival of two stonecrops (Sedum spp.) and six nonsucculent natives to the midwestern U.S. prairie over a period of 3 years. A second study evaluated these same plant types that were supplied with four levels of controlled-release fertilizer. Both studies were conducted at ground level in interlocking modular units (36 ^D#^DOE 36 inches) designed for green roof applications containing 10 cm of substrate. Higher levels of heat-expanded slate in the substrate generally resulted in slightly less growth and lower visual ratings across all species. By May 2004, all plants of smooth aster (Aster laevis), horsemint (Monarda punctata), black-eyed susan (Rudbeckia hirta), and showy goldenrod (Solidago speciosa) were dead. To a lesser degree, half of the lanceleaf coreopsis (Coreopsis lanceolata) survived in 60% and 70% heat-expanded slate, but only a third of the plants survived in 80%, 90%, or 100%. Regardless of substrate composition, both 'Diffusum' stonecrop (S. middendorffianum) and Royal Pink stonecrop (S. spurium) achieved 100% coverage by June 2002 and maintained this coverage into 2004. In the fertility study, plants that received low fertilizer rates generally produced the least amount of growth. However, water availability was a key factor. A greater number of smooth aster, junegrass (Koeleria macrantha), and showy goldenrod plants survived when they were not fertilized. Presumably, these plants could survive drought conditions for a longer period of time since they had less biomass to maintain. However, by the end of three growing seasons, all three nonsucculent natives also were dead. Overall results suggest that a moderately high level of heat-expanded slate (about 80%) and a relatively low level of controlled-release fertilizer (50 g·m-2 per year) can be utilized for green roof applications when growing succulents such as stonecrop. However, the nonsucculents used in this study require deeper substrates, additional organic matter, or supplemental irrigation. By reducing the amount of organic matter in the substrate and by applying the minimal amount of fertilizer to maintain plant health, potential contaminated discharge of N, P, and other nutrients from green roofs is likely to be reduced considerably while still maintaining plant health." |
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| Language: | English |
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| References: | 25 |
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| Note: | Summary appears as abstract
Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Rowe, D. B., M. A. Monterusso, and C. Rugh. 2006. Assessment of heat-expanded slate and fertility requirements in green roof substrates. HortTechnology. 16(3):p. 471-477. |
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| DOI: 10.21273/HORTTECH.16.3.0471 |
| Web URL(s):
https://journals.ashs.org/horttech/view/journals/horttech/16/3/article-p471.xml?rskey=0WXQFC
Last checked: 11/20/2019
Requires: PDF Reader |
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MSU catalog number: SB 317.5 .H6 |
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