Switchgrass

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iSwitchgrass

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Liliopsida
Order:	Poales
Family:	Poaceae
Genus:	Panicum
Species:	P. virgatum

Binomial name

Panicum virgatum
L.

Switchgrass (Panicum virgatum), also called Tall Panic Grass, is a warm-season plant (C4 carbon fixation) and is one of the dominant species of the central North America tallgrass prairie. Switchgrass can be found in remnant prairies, along roadsides, pastures, and as an ornamental in gardens. Other common names for this grass include Wobsqua grass, lowland switchgrass, blackbent, tall prairiegrass, wild redtop, and thatchgrass.

This hardy, perennial grass begins growth in late spring. It can grow up to 1.8-2.2 m in height, but is typically shorter than Big Bluestem Grass (Andropogon gerardii) or Indiangrass (Sorghastrum nutans). The leaves are 30-90 cm long with a prominent midrib.

Its flowers have a well-developed panicle often up to 60 cm in length and bears a good crop of fruits, which are 3 to 6 mm long and up to 1.5 mm wide. The fruits 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 short rhizomatous plant that tends to resemble a bunch grass. As an ornamental grass, it is easily grown in average to wet soils and in full sun to part shade. It is very drought resistant. Establishment is recommended in the spring, at the same time as maize is planted.

Switchgrass is grazed by different types of animals. Many farmers grow switchgrass, either as forage for livestock, in wildlife areas, or as a ground cover, to control erosion.

Due to its hardiness and rapid growth, switchgrass is often considered a good candidate for farming as feedstock or for biofuel production (for example, ethanol). It was in this context that President George W. Bush mentioned it in his 2006 State of the Union address. Switchgrass has the potential to produce the biomass required for production of up to 400 liters of ethanol per metric tonne. A high yield like this makes it a very attractive crop to grow as the value by far exceeds any other crop. Yet, some studies claim that switchgrass is not a viable alternative, requiring 45 percent more fossil energy than the fuel produced [1]. David Bransby, professor of energy crops at Auburn University, disagrees. He argues that for every unit of energy input, switchgrass yields four units out. The viability of switchgrass-derived biofuel as an alternative fuel remains contentious.