Panicum virgatum

Taxobox
name = Switchgrass


image_width = 240px
regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Poales
familia = Poaceae
genus = "Panicum"
species = "P. virgatum"
binomial = "Panicum virgatum"
binomial_authority = L.

"Panicum virgatum", commonly known as switchgrass, is a warm season grass and is one of the dominant species of the central North American tallgrass prairie. It can be found in remnant prairies, along roadsides, pastures and as an ornamental plant in gardens. Other common names for it include tall panic grass, Wobsqua grass, lowland switchgrass, blackbent, tall prairiegrass, wild redtop and thatchgrass. In his 2006 State of the Union Address, President George W. Bush touted switchgrass as an efficient and environmentally friendly biofuel that could reduce the USA's dependence on petroleum.

Properties

Switchgrass is a hardy, perennial rhizomatous grass which begins growth in late spring. It can grow up to 1.8-2.2 m high but is typically shorter than Big Bluestem grass or Indiangrass. The leaves are 30-90 cm long, with a prominent midrib. Switchgrass uses C₄ carbon fixation, giving it an advantage in conditions of drought and high temperature.cite web
last = Silzer
first =Tanya
title =Panicum virgatum L., Switchgrass, prairie switchgrass, tall panic grass
work =Rangeland Ecosystems & Plants Fact Sheets
publisher =University of Saskatchewan Department of Plant Sciences
month=January | year=2000
url =http://www.usask.ca/agriculture/plantsci/classes/range/panicum.html
accessdate = 2007-12-08 ] Its flowers have a well-developed panicle, often up to 60 cm long and bear a good crop of fruits. The fruits are 3-6 mm long and up to 1.5 mm wide, and are developed from a single-flowered spikelet. Both glumes are present and well developed. When ripe, the seeds sometimes take on a pink or dull-purple tinge, and turn golden brown with the foliage of the plant in the fall. Switchgrass is a self-seeding crop, which means farmers do not have to plant and re-seed after annual harvesting. Once established, a switchgrass stand can survive for ten years or longer.cite web
url=http://www.signonsandiego.com/uniontrib/20061221/news_lz1c21grass.html
title=Plentiful switch grass emerges as breakthrough biofuel | The San Diego Union-Tribune
publisher=The San Diego Union-Tribune
accessdate=2008-05-24
last=Secter
first=Bob] Also, unlike corn, switchgrass can grow on marginal lands and requires little or no fertilizer to thrive.

Background

Much of North America, especially the prairies of the Midwestern United States, was once prime habitat to vast swaths of native grasses including Switchgrass ("Panicum virgatum"), Indiangrass ("Sorghastrum nutans"), Eastern Gamagrass ("Tripsacum dactyloides"), Big Bluestem ("Andropogon gerardii"), Little Bluestem ("Schizachyrium scoparium") and others. As European settlers began spreading west across the continent, the native grasses were displaced by large farms growing crops such as corn and wheat. Introduced grasses such as fescue, bluegrass, and orchardgrass cite web
last =Ernst Seed Catalog Web Page
first =
title =Switchgrass and Warm Season Grass Planting Guide
publisher =Ernst Conservation Seeds
year =2007
url =http://www.ernstseed.com/switchgrass_planting_quide.htm
accessdate = 2007-12-08 ] also replaced the native grasses.

Distribution

Switchgrass is a very versatile and adaptable plant. It can grow and even thrive in many weather conditions, lengths of growing seasons, soil types and land conditions. Its distribution spans south of latitude 55°N from Saskatchewan to Nova Scotia and south over most of the United States east of the Rocky Mountains.cite web
url=http://plants.usda.gov/java/profile?symbol=PAVI2
title=PLANTS Profile for Panicum virgatum (switchgrass)
publisher=United States Department of Agriculture, Natural Resources Conservation Service
accessdate=2008-05-21
last=
first=] As a warm season perennial grass, most of its growth occurs from late spring through early fall, becoming dormant and unproductive during colder months. Thus, the productive season in its northern habitat can be as short as three months, but in the southern reaches of its habitat, the growing season may be as long as eight months around the Gulf Coast area.cite book
last = Ball
first = D.M.
authorlink =
coauthors = Hoveland, C.S., and Lacefield, G.D.
title = Southern Forages
publisher = International Plant Nutrition Institute
edition=3rd edition
year = 2002
location =
pages = p. 26
url = http://www.ipni.net/e-catalog/BOOKS/95-1033/sf.HTM
doi =
id =
isbn = 0-9629598-3-9]

Switchgrass’ suitability for cultivation in the Gran Chaco is currently studied by Argentina’s INTA [cite news
title = Aprovechamiento de recursos vegetales y animales para la produccion de biocombustibles
language = Spanish
publisher = INTA
date = 26 June 2008
url = http://www.inta.gov.ar/iir/investiga/proyectos/pebiocombustibles.pdf ]

Establishment

Once established, it takes three years for a stand of switchgrass to reach its full potential. According to David Bransby at Auburn University, it will produce a quarter to a third of its full potential in its first year and two-thirds in its second yearcite web
url=http://bioenergy.ornl.gov/papers/misc/switchgrass-profile.html
title=Switchgrass Profile
publisher=Bioenergy Feedstock Information Network (BFIN), Oak Ridge National Laboratory
accessdate=2008-05-24
last=Bransby
first=David
year=2005] . It is sometimes suggested that the stand not be harvested during the establishment year. Afterwards, each region has its own recommendations for fertilizer rates. The timing of harvesting depends upon how the switchgrass is to be used, and weed control can be addressed with limited herbicides, controlled burns, and mechanical methods.

Uses

Switchgrass is grazed by certain animals, used as ground cover to control erosion, and farmed as forage for livestock.

Switchgrass is rich in cellulose, making it attractive as a source for cellulosic ethanol. [cite journal | author=M. R. Schmer, K. P. Vogel, R. B. Mitchell, and R. K. Perrin |title=Net energy of cellulosic ethanol from switchgrass |journal=PNAS |volume=105 |issue= 2 |pages= 464–469 |year= 2008 |doi= 10.1073/pnas.0704767105 |pmid=18180449 ] It is at the core of an alternative fuel strategy announced by Tennessee Governor Phil Bredesen in January 2007. [ [http://www.tennesseeanytime.org/governor/viewArticleContent.do?id=968 Phil Bredesen Governor, State of Tennessee ] ]

As a drought resistant ornamental grass, it is easily grown in average to wet soils and in full sun to part shade. Establishment is recommended in the spring, at the same time as corn is planted.

Soil conservation

Switchgrass is useful for soil conservation and amendment, particularly in the United States and Canada where switchgrass is endemic. Switchgrass has a deep fibrous root system – nearly as deep as the plant is tall. Since it, along with other native grasses and forbs, once covered the plains of the United States that are now the Corn Belt, the effects of the past switchgrass habitat has been beneficial, lending to the fertile farmland that exists today. The deep fibrous root systems of switchgrass left a very deep rich layer of organic matter in the soils of the midwest; making those mollisol soils some of the most productive in the world. By returning switchgrass and other perennial prairie grasses as an agricultural crop, many marginal soils may benefit from increased levels of organic material, permeability, and fertility from the grass's deep root system.

Soil erosion, both from wind and water, is of great concern in regions where switchgrass grows. Due to its height, switchgrass can form an effective wind erosion barrier.cite web
url=http://plants.usda.gov/factsheet/pdf/fs_pavi2.pdf
title=Plant Fact Sheet, Panicum virgatum (switchgrass)
publisher=United States Department of Agriculture, Natural Resources Conservation Service, Plant Materials Program
accessdate=2008-05-21
last=
first=
date=2006-05-06
format=PDF] Its root system, also, is excellent for holding soil in place, which helps prevent erosion from flooding and runoff.Some highway departments (for example, KDOT) have used switchgrasses in their seed mixes when re-establishing growth along roadways.cite web
url=http://www.ksdot.org/burConsMain/bidtabs/bidtab.asp?yr=2008&id=08034232
title=KDOT Bid Tabs
publisher=Kansas Department of Transportation
accessdate=2008-05-20
last=
first=] It can also be used on strip mine sites, dikes, and pond dams. Conservation districts in many parts of the United States use it to control erosion in grass waterways because of its excellent ability to anchor soils while also doubling as native habitat for wildlife.

Game cover

Switchgrass is well-known among wildlife conservationists as a favorite forage and habitat among upland game bird species such as pheasant, quail, grouse, wild turkey, and song birds, with its plentiful small seeds and tall cover. Depending on how thickly switchgrass is planted, and what it is partnered with, it also offers excellent forage and cover for a wide variety of other wildlife across the country. For those producers who have switchgrass stands on their farm, it is considered an environmental and aesthetic benefit due to the abundance of wildlife attracted by the switchgrass stands. Some members of Prairie Lands Bio-Products, Inc. in Iowa have even turned this benefit into a profitable business by leasing their switchgrass land for hunting during the proper seasons.cite conference
first = Patricia C.
last = Hipple
authorlink =
coauthors = Duffy, Michael D.
date =
year = 2002
month =
title = Farmers' Motivations for Adoption of Switchgrass
conference = Fifth National Symposium, New Crops and New Uses, Strength in Diversity
conferenceurl = http://www.hort.purdue.edu/newcrop/ncnu02/pdf/default.html
booktitle = Trends in New Crops and New Uses
editor = Jules Janick, Anna Whipkey
others =
volume =
edition =
publisher = American Society for Horticultural Science
location = Alexandria, Virginia
pages = 252-266
url = http://www.hort.purdue.edu/newcrop/ncnu02/pdf/duffy-252.pdf
format = PDF
accessdate = 2008-05-23
doi =
id = ISBN 0097075655
oclc =] The benefits to wildlife can be extended even in large scale agriculture through the process of strip harvesting as recommended by the Wildlife Society, which suggests that rather than harvesting an entire fields at once, strip harvesting could be practiced so the entire habitat is not removed thereby protecting the wildlife that has inhabited the switchgrass.Cite journal
doi = 10.2193/0091-7648(2006)34 [1203:TBEIGE] 2.0.CO;2
volume = 34
issue = 4
pages = 1203–1205
last = Bies
first = Laura
title = The Biofuels Explosion: Is Green Energy Good for Wildlife?
journal = Wildlife Society Bulletin
accessdate = 2008-05-24
date = 2006-11-01
year = 2006]

Biofuel

date=2007-01-23] .

Switchgrass has the potential for enough biomass to produce up to 100 gallons (380 liters) of ethanol per metric ton harvested. [cite web|url= http://www.prognog.com/driving/ethanol/switchgrass:__native_american_powerhouse.html|title=Switchgrass: Native American Powerhouse?|publisher=Renewable Energy Resources|accessdate=2007-01-05] This gives switchgrass the potential to produce 1,000 gallons of ethanol per acre, compared to 665 gallons per acre of sugarcane and 400 gallons per acre of corn. [cite web|url= http://www.seco.cpa.state.tx.us/re_biomass-crops.htm|title=Biomass Energy: Growing Crops For Fuel|publisher=Texas State Energy Conservation Office|accessdate=2007-01-05]

However, there is debate on the economic and environmental viability of switchgrass, and all other biofuels, as an efficient energy source. In recent studies, it has been argued that switchgrass has a negative ethanol fuel energy balance, requiring 45 percent more fossil energy to create switchgrass into a biofuel than is produced. [cite web|url= http://www.sciencedaily.com/releases/2005/07/050705231841.htm|title=Ethanol And Biodiesel From Crops Not Worth The Energy|publisher=ScienceDaily|accessdate=2007-01-05] Some studies have countered these arguments, however, finding that for every unit of energy input to create a biofuel from switchgrass, four units of energy are yielded. [cite web|url= http://www.npr.org/templates/story/story.php?storyId=5183608|title=Switch Grass: Alternative Energy Source?|publisher=NPR|accessdate=2007-01-05] In a 2007 lecture Professor Richard Muller, of the University of California, Berkeley, noted that it is the conversion of switchgrass biomass, mainly cellulose, into ethanol which introduces significant inefficiencies. It was also noted that The Helios Project at Lawrence Berkeley Laboratory is actively trying to engineer metabolic pathways in bacteria to convert cellulose to ethanol more efficiently.

Switchgrass is being used to heat small industrial and farm buildings in Germany and China through a process used to make a low quality natural gas substitute. It can also be pressed into fuel pellets which are burned in pellet stoves used to heat homes, which typically burn corn or wood pellets.cite web
url=http://www.reap-canada.com/library/Bioenergy/2007%20SG%20production%20guide-FINAL.pdf
title=Switchgrass Production in Ontario: A Management Guide
publisher=Resource Efficient Agricultural Production (REAP) - Canada
accessdate=2008-05-24
last=Samson
first=R.
year=2007
format=PDF]

In the spring of 2008, convert|1000|acre|km2 of switchgrass will be planted near Guymon, Oklahoma, in the Oklahoma Panhandle to study the feasibility of using the crop for biofuel. It will be the largest stand ever planted for such purposes. The project is being spearheaded by the Oklahoma Bioenergy Center, a state project backed by Governor Brad Henry. [ [http://www.farmanddairy.com/news/oklahoma-to-plant-largest-stand-of-switchgrass-ever-for-fuel-research/ Oklahoma to plant largest stand of switchgrass ever for fuel research | Farm and Dairy - The Auction Guide and Rural Marketplace ] ]

Forages

Switchgrass is an excellent forage for cattle; however, it has shown toxicity in horses, sheep and goatscite journal
author = Lee, S.T.
coauthors = Stegelmeier, B.L.; Gardner, D.R.; Vogel, K.P.
year = 2001
title = The isolation and identification of steroidal sapogenins in switchgrass
journal = J Nat Toxins
volume = 10
issue = 4
pages = 273–81
url = http://www.ncbi.nlm.nih.gov/pubmed/11695816
accessdate = 2008-05-24] cite journal
author = Johnson, A.L.
coauthors = Divers, T.J.; Freckleton, M.L.; McKenzie, H.C.; Mitchell, E.; Cullen, J.M.; McDonough, S.P.
year = 2006
title = Fall Panicum (Panicum dichotomiflorum) Hepatotoxicosis in Horses and Sheep
journal = Journal of Veterinary Internal Medicine
volume = 20
issue = 6
pages = 1414–1421
url = http://www.jvetintmed.org/perlserv/?request=get-abstract&doi=10.1892%2F0891-6640(2006)20%5B1414%3AFPPDHI%5D2.0.CO%3B2
accessdate = 2008-05-24
doi = 10.1892/0891-6640(2006)20 [1414:FPPDHI] 2.0.CO;2] cite journal
author = Stegelmeier, B.L.
coauthors = Elmore, S.A.; Lee, S.T.; James, L.F.; Gardner, D.R.; Panter, K.E.; Ralphs, M.H.; Pfister, J.A.
year = 2007
title = Switchgrass (panicum Virgatum) Toxicity In Rodents, Sheep, Goats And Horses
journal = Poisonous Plant Global Research and Solutions
volume = 19
pages = 113–117
url = http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=186737
accessdate = 2008-05-24] through chemical compounds known as saponins, which cause photosensitivity and liver damage in these animals. Researchers are continuing to learn more about the specific conditions under which the switchgrass must be in order to cause harm to these species, but until more is discovered, it is recommended that switchgrass not be fed to them. For cattle, however, it can be fed as hay, or grazed.

Grazing switchgrass calls for watchful management practices to ensure survival of the stand. It is recommended that grazing begin when there is 18 – 22 inches of growth, to stop grazing when there are 8 – 12 inches of stubble left, and to rest the pasture 30 – 45 days between grazing periodsCite book
last = Ball
first = D.M.
authorlink =
coauthors = Hoveland, C.S., and Lacefield, G.D.
title = Forage Crop Pocket Guide
publisher = International Plant Nutrition Institute
year = 2006
location =
chapter = Table 28. Guidelines for rotational stocking of selected forage crops
url = http://www.ipni.net/e-catalog/BOOKS/32-0001/pg.HTM
doi =
id =
isbn = ] . Switchgrass becomes very stemmy and unpalatable as it matures, but during the target grazing period, it is a highly favorable forage with a relative feed value (RFV) of 90-104Cite book
last = Ball
first = D.M.
authorlink =
coauthors = Hoveland, C.S., and Lacefield, G.D.
title = Forage Crop Pocket Guide
publisher = International Plant Nutrition Institute
year = 2006
location =
chapter = Table 33b. Total Digestible Nutrients (TDN) and Relative Feed Value (RFV) Ranges for Various Forage Crops
url = http://www.ipni.net/e-catalog/BOOKS/32-0001/pg.HTM
doi =
id =
isbn = ] . The grass' upright growth pattern places its growing point off the soil surface onto its stem, so leaving 8 – 12 inches of stubble is important for regrowth. When harvesting switchgrass for hay, the first cutting occurs at the late boot stage – around mid-June. This should allow for a second cutting in mid-August, leaving enough regrowth to survive the winter.cite journal
author = Wolf, D.D.
coauthors = Fiske, D.A.
year = 1995
title = Planting and managing switchgrass for forage, wildlife, and conservation
journal = Virginia Cooperative Extension Publication
pages = 418–013
url = http://www.ext.vt.edu/pubs/forage/418-013/418-013.pdf
format = PDF
accessdate = 2008-05-24]

Preservation of native plant species

There is another type of conservation that doesn't draw as much attention as soil and wildlife conservation normally does: the conservation of our native plant species, such as switchgrass. By bringing switchgrass to the front of the news, Americans are revisiting a part of their nation's past that many have perhaps never thought about: when North America was covered in "that vast seas of grasses, so thick and high that pioneers said it could swallow a rider on horseback." Maybe this will stir interest by a broader spectrum of the population in switchgrass and other native species that were once a part of our landscape which have gone to the wayside. Several groups help inform the public about native plant species, such as a scholarly group at the University of Idaho which publishes the Native Plants Journalcite web
url=http://nativeplants.for.uidaho.edu/journal/
title=About the Journal
publisher=Native Plants Journal
accessdate=2008-05-29
last=
first=] to educate the public about native plant species, as well as groups like Grow Native!, [cite web
url=http://www.grownative.org/index.cfm?fuseaction=about.main
title=About Grow Native!
publisher=Grow Native!
accessdate=2008-05-29
last=
first=] international organizations such as the National Audubon Society, and state organizations like the Virginia Native Plant Society.cite web
url=http://www.vnps.org/
title=Virginia Native Plant Society
publisher=
accessdate=2008-05-29
last=
first=] These groups offer information and anecdotes about native species' habitat, history, pests, growth patterns, positive and negative attributes.

= See also =
* Algae fuel
* Brachypodium distachyon
* Energy crop
* Proceedings of the National Academy of Sciences

References

External links

* [http://www.planetark.com/dailynewsstory.cfm/newsid/46338/story.htm Switchgrass Fuel Yields Bountiful Energy]
* [http://littlebloginthebigwoods.blogspot.com/2007/10/fuelish-fantasies.html The Switchgrass Fantasy]
* [http://www.eap.mcgill.ca/MagRack/SF/Fall%2091%20L.htm "Switchgrass: A Living Solar Battery." Roger Samson (Online reprint)]
* http://bioenergy.ornl.gov/papers/misc/switchgrass-profile.html
* [http://www.agecon.uga.edu/~caed/Pubs/switchgrass.html Economics of switchgrass production]
* [http://www.ars.usda.gov/is/pr/2006/060310.htm USDA Studies Switchgrass for Ethanol and Energy Production]
* [http://www.switchgrass.nl/ Switchgrass as an Alternative Energy crop] - European Union study on Switchgrass feasibility.
* [http://www.sbs.utexas.edu/mbierner/bio406d/images/pics/poa/panicum_virgatum.htm Switchgrass images] - Archive of Central Texas Plants
* [http://www.eeob.iastate.edu/research/iowagrasses/speciespages/PanicVirga/PanicVirga.html Switchgrass images] - Has closeup photos of spikelets
* [http://www.switch-grass.com Switch Grass Information Repository] - General information repository on switch grass usage and feasible application as an alternative energy
* [http://www.sciam.com/article.cfm?id=grass-makes-better-ethanol-than-corn "Grass Makes Better Ethanol than Corn Does"] - Scientific American article on the potential use of switchgrass for biofuels
* [http://www.renewableenergyaccess.com/rea/news/story?id=51107 Study Shows Great Potential of Switchgrass as Biofuel Feedstock]