English

Noun

1. A tall North American perennial grass, Panicum virgatum, used as forage and to make hay.

Translations

See also

• panic grass

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. 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. Also, unlike corn, switchgrass can grow on marginal lands and requires little or no fertilizer to thrive. It is at the core of an alternative fuel strategy announced by Tennessee Governor Phil Bredesen in January 2007.

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.

Background

Much of North America, especially the prairies of the Midwest, was once home 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 settlers began spreading out across the continent, the native grasses were replaced by crops such as corn and wheat. Introduced grasses such as fescue, bluegrass, and orchardgrass replaced the native grasses.

Today, as biofuels are becoming a mainstay in the headlines, the public is hearing about Switchgrass as an excellent prospect for providing ethanol for our cars. There are also other benefits and opportunities for switchgrass in our economy.

Distribution

Switchgrass is very versatile and adaptable. 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. As a warm season perennial grass, most of its growth occurs from late spring through early fall and becomes dormant and unproductive during colder months. Thus, the productive season in the northern regions can be as short as three months, but up to eight months in the Gulf Coast area.

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, one could say that they still help feed the world today. Their deep fibrous roots left a very deep rich layer of organic matter in the soils; making those mollisol soils some of the most productive in the world. By returning switchgrass and other perennial prairie grasses to the agricultural scene, many marginal soils will benefit from their deep root systems through increased organic matter levels, permeability, and fertility.

Soil erosion, both from wind and water, is of great concern in regions where switchgrass can grow. Due to its height, switchgrass can form the low part of a wind erosion barrier. Its root system is excellent for holding soil in place. Some highway departments (for example, KDOT) have used it in their seed mixes when re-establishing growth along roadways. It can also be used on strip mine sites, dikes In an agricultural setting, like growing many acres of switchgrass for biofuel, the advantages to wildlife can still stand. Although the Wildlife Society suggests that rather than harvest an entire field at once, strip harvesting could be practiced so the entire habitat is not removed at one time for the wildlife that have made the switchgrass their home.

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 American was covered in "that vast seas of grasses, so thick and high that pioneers said it could swallow a rider on horseback." to educate the public about native plant species, as well as groups like Grow Native!, international organizations such as the National Audubon Society, and state organizations like the Virginia Native Plant Society. These groups offer information and anecdotes about native species' habitat, history, pests, growth patterns, positive and negative attributes.

Biofuel

• Brachypodium distachyon
• Energy crop
• Proceedings of the National Academy of Sciences

References

External links

• Switchgrass Fuel Yields Bountiful Energy
• "Switchgrass: A Living Solar Battery." Roger Samson (Online reprint)
• http://bioenergy.ornl.gov/papers/misc/switchgrass-profile.html
• Economics of switchgrass production
• USDA Studies Switchgrass for Ethanol and Energy Production
• Switchgrass as an Alternative Energy crop - European Union study on Switchgrass feasibility.
• Switchgrass images - Archive of Central Texas Plants
• Switchgrass images - Has closeup photos of spikelets
• Switch Grass Information Repository - General information repository on switch grass usage and feasible application as an alternative energy
• "Grass Makes Better Ethanol than Corn Does" - Scientific American article on the potential use of switchgrass for biofuels
• Study Shows Great Potential of Switchgrass as Biofuel Feedstock