Navigation Links
How does your green roof garden grow?
Date:12/29/2010

UNIVERSITY PARK, PA -- Growing plants on rooftops is an old concept that has evolved from simple sod roofing to roof gardens and new, lightweight "extensive green roofs". Modern green roofs have environmental and social benefits; they can reduce stormwater runoff, improve air quality, mitigate urban heat, reduce the demand for air conditioning and greenhouse gas emissions, and provide habitat for birds and wildlife. Long-used in urban planning in Europe, green roofs are becoming more popular in North America, and new research designed to promote the integration of green roofs into current and future buildings is burgeoning. Researchers from the Department of Horticulture at The Pennsylvania State University published a study in HortTechnology that evaluated the influence of substrate type and depth on establishment of five common green roof plants.

Plants suitable for extensive green roofs must tolerate extreme rooftop conditions, and the substrates in which they grow must meet both horticultural and structural requirements. Deeper substrates may retain more water for plants during dry periods, but they also weigh more, especially when near saturation. The study by Christine E. Thuring, Robert D. Berghage, and David J. Beattie was designed to evaluate the effects of substrate type and depth on the establishment and early growth of five plants popular in North American green roof designs.

The researchers hypothesized that early drought is more harmful for plants grown in shallow rather than deeper substrate depths, and that plants that survived early drought conditions would produce less shoot biomass than those subjected to late drought. Two stonecrops, one ice plant, and two herbaceous perennials were planted in three depths (30, 60, and 120 mm) of expanded shale and expanded clay, two commercially available green roof substrates. Study flats inside a plasticulture tunnel received three drought treatments: no drought, 2 weeks early drought, and 2 weeks late drought.

The two stonecrops performed well under most conditions, although tasteless stonecrop was stunted by early drought. Ice plant performed erratically and, along with maiden pink, poorly in face of drought during establishment. When subjected to any drought, the herbaceous perennials had the fewest survivors in the expanded shale. The study plants were most affected by substrate depth, except for maiden pink, which responded solely to drought. When subjected to early drought conditions, the herbaceous perennials did not survive in 30 mm of either substrate, or in 60 mm of expanded shale; early drought appeared to be more harmful to plant survival and performance than late drought. Although the stonecrops performed well in 60 mm of substrate when subjected to drought, their performance was superior in the expanded clay compared with shale.

The three most resilient species used in the studysaxifrage pink, white stonecrop, and tasteless stonecropalways produced more shoot biomass with increasing substrate depth, regardless of water availability. A standout performer was saxifrage pink, which had an attractive appearance and persistent flowering habit, making it an excellent choice as a green roof plant.

The experiment illustrates how appropriate species selection in the design of unirrigated extensive green roofs may be directed by factors such as substrate type and depth, as well as anticipated drought conditions. "This experiment revealed the variability among drought-tolerant species to various treatments, as well as the different plant responses to substrate type during drought", concluded the scientists.


'/>"/>

Contact: Michael W. Neff
mwneff@ashs.org
703-836-4606
American Society for Horticultural Science
Source:Eurekalert

Related biology news :

1. New technology improves greenhouse, plant microclimates
2. Blue-green algae tested for treating ALS
3. Rising greenhouse gases profoundly impact microscopic marine life
4. Global rivers emit 3 times IPCC estimates of greenhouse gas nitrous oxide
5. Waterways contribute to growth of potent greenhouse gas
6. New study about Arctic sea-ice, greenhouse gases and polar bear habitat
7. Green genes in yeast may boost biofuel production by increasing stress tolerance
8. Pitt study finds green water treatments may not kill bacteria in large building cooling systems
9. Diners may be willing to pay more to eat at green restaurants
10. Greener climate prediction shows plants slow warming
11. Record-high greenhouse gas concentrations
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/21/2017)... -- Der weltweite Biobanking-Sektor wird bis zum ... mit mehr als 50 Vertretern aus verschiedenen Branchen wurde aber ... diese Prognose zu realisieren. ... Zu den Schwierigkeiten für ... für die Biobank, die Implementierung Zeit sparender Technologien, ein ...
(Date:2/13/2017)... FRANCISCO , Feb. 13, 2017  RSA ... centralized platform that is designed to enhance fraud ... latest release in the RSA Fraud & Risk ... enable organizations to leverage additional insights from internal ... tools to better protect their customers from targeted ...
(Date:2/9/2017)... LONDON , Feb. 9, 2017 The ... in-depth analysis of the biomass boiler market globally in ... sales of biomass boilers. The market for biomass boilers ... product type, end-user, application, and country/region. The market based ... agriculture & forest residues, biogas & energy crops, urban ...
Breaking Biology News(10 mins):
(Date:2/24/2017)... 24, 2017  Aethlon Medical, Inc. (Nasdaq: ... its Chairman and CEO, Jim Joyce . ... Conference last Saturday, Bill Gates warned world ... people than nuclear weapons. Mr. Gates expressed his concern, ... agencies, that scientific terrorists have access to the necessary ...
(Date:2/24/2017)... 2017 China Cord Blood Corporation (NYSE: ... provider of cord blood collection, laboratory testing, hematopoietic stem ... its unaudited financial results for the third quarter and ... 31, 2016. Third Quarter of Fiscal 2017 ... of fiscal 2017 increased by 18.6% to RMB200.9 million ...
(Date:2/24/2017)... Pa., Feb. 24, 2017  VWR Corporation (NASDAQ: VWR), the ... laboratory and production customers, today reported its financial results for ... Highlights: 4Q16 record quarterly ... 1.0% on an organic basis. ... an organic basis, while the Americas net sales increased 2.5%, ...
(Date:2/23/2017)... 23, 2017 ... per share data, unaudited)Three Months Ended December 31,Twelve Months ... $         ...   89026%Aldurazyme Net Product Revenue ... Net Product Revenue  756025%297303(2)%Vimizim Net ...
Breaking Biology Technology: