Switchgrass facts for kids

Quick facts for kids Switchgrass
Conservation status
Secure (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Clade:	Commelinids
Order:	Poales
Family:	Poaceae
Genus:	Panicum
Species:	P. virgatum
Binomial name
Panicum virgatum L.
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Panicum virgatum, also known as switchgrass, is a special type of grass that lives for many years. It grows naturally across North America, from Canada all the way down to the United States and Mexico. Switchgrass is a very important plant in the central tallgrass prairies of North America. You can find it in natural grasslands, pastures, and along roadsides.

People use switchgrass for many things. It helps protect soil, provides food for animals, and offers shelter for wildlife. It's also used as a pretty plant in gardens. Scientists are even using it to clean up polluted soil and to make renewable energy like ethanol and butanol. This grass helps capture carbon dioxide from the air, which is good for our planet.

Other common names for switchgrass include tall panic grass, Wobsqua grass, and thatchgrass.

How Switchgrass Looks

Switchgrass is a tough plant with deep roots that grows back every year. It starts growing in late spring. This grass can reach up to 2.7 meters (about 9 feet) tall, but it's usually a bit shorter than other tall prairie grasses. Its leaves are long, about 30 to 90 centimeters (1 to 3 feet), and have a clear line down the middle.

Switchgrass is special because it uses a process called C₄ carbon fixation. This helps it grow well even when it's dry and hot. Its flowers grow in a large, branching cluster, often up to 60 centimeters (2 feet) long. These flowers produce many seeds. The seeds are small, about 3 to 6 millimeters long. When they are ready, the seeds can look pink or purple before turning golden brown in the fall.

One great thing about switchgrass is that it's a perennial plant and can reseed itself. This means farmers don't have to plant new seeds every year. Once it's growing, a field of switchgrass can last for ten years or more! Unlike corn, switchgrass can grow on land that isn't perfect for other crops. It also needs less fertilizer. This makes it a very efficient plant for producing energy from farmland.

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  Root system of switchgrass grown at the Land Institute

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  Seeds of switchgrass

Where Switchgrass Grows Naturally

Long ago, much of North America, especially the central United States, was covered in vast areas of native grasses like switchgrass. Other important grasses included indiangrass and big bluestem. When European settlers came, they plowed these native grasslands to grow crops like corn and wheat. New grasses were also brought in for hay and animal pastures.

Switchgrass is a very adaptable plant. It can grow well in many different weather conditions, soil types, and land conditions. It grows from Saskatchewan in Canada, across most of the United States east of the Rocky Mountains, and south into Mexico. Since it's a warm-season grass, it grows mostly from late spring to early fall. It rests during the colder months. This means its growing season can be as short as three months in the north or as long as eight months near the Gulf Coast.

There are different types of switchgrass, which have adapted to various environments. These differences are helpful for scientists who want to breed new varieties. There are two main forms:

• Lowland cultivars: These types usually grow taller and produce more plant material.
• Upland cultivars: These types are often found in northern areas and can handle cold weather better. They are generally shorter and less coarse.

Both types have deep roots, often more than 1.8 meters (6 feet) deep in good soil. In natural prairies, switchgrass often grows alongside other tall prairie plants like big bluestem, indiangrass, and various wildflowers.

Panicum virgatum different types and where they grow in the U.S.A.

Growing and Caring for Switchgrass

Switchgrass can grow on land that isn't good for other crops. This includes land that easily washes away or sandy and rocky soils. There isn't just one way to plant switchgrass. Farmers can plant it without tilling the soil (no-till) or by preparing the soil first (conventional tillage).

Here are some tips for successfully planting switchgrass:

• Plant it in the spring after the soil has warmed up.
• Use good quality seeds and plant them about 0.6 to 1.2 centimeters (about half an inch) deep. In sandy soils, they can be planted up to 2 centimeters (almost an inch) deep.
• Press the soil down firmly both before and after planting the seeds.
• Don't use fertilizer when planting. This helps reduce competition from weeds.
• Control weeds using special chemicals (herbicides) or by mowing. Mowing weeds just above the height of the young switchgrass is a good method.

Sometimes, a new switchgrass field might look like it's failing because of too many weeds. But often, with good care in the next few years, the switchgrass will grow strong. Once planted, it can take up to three years for switchgrass to reach its full growth potential.

After it's established, how you manage switchgrass depends on what you want to use it for. For example, if it's for wildlife, you might mow or burn parts of the field occasionally to help different plants and animals thrive. If it's for energy, it usually needs a small amount of nitrogen fertilizer. Switchgrass is very good at competing with weeds, so herbicides are not often needed after the first year.

Switchgrass can be harvested once or twice a year. Farmers can use the same equipment they use for harvesting hay. It's easy to bale or collect in bulk. If managed correctly, switchgrass has great potential as an energy crop.

How We Use Switchgrass

Switchgrass is a very useful plant! It can be used to make energy, protect soil, prevent erosion, feed animals, provide shelter for wildlife, and even make special plastics. Farmers use it for hay and pasture for cattle. It can also replace wheat straw for animal bedding or in building straw bale houses.

Panicum virgatum 'Heavy Metal', a type of switchgrass grown for its beauty, in early summer

People also grow switchgrass in gardens because it's pretty and can handle dry weather. It grows well in sunny spots or partial shade.

Switchgrass for Wildlife

Switchgrass is a favorite plant for the caterpillars of certain moths, like the Dargida rubripennis moth. It also provides food for the caterpillars of butterflies like the Delaware skipper and the Hobomok skipper.

Wildlife experts know that switchgrass is excellent for game birds like pheasants, quail, and wild turkeys. It provides them with small seeds to eat and tall cover to hide in. It also helps many songbirds. Farmers who have switchgrass fields often see lots of wildlife, which is a great benefit. Some farmers even lease their land for hunting during certain seasons. To help wildlife even more, farmers can harvest switchgrass in strips instead of clearing the whole field at once. This way, animals always have a place to live.

Switchgrass for Fuel and Energy

Since the 1980s, scientists have studied switchgrass as a way to make renewable energy. It's a native grass that grows for many years and can produce a lot of plant material even on less fertile land. Today, it's being used to make cellulosic ethanol, biogas, and for burning to create heat.

The best things about switchgrass for energy are that it lives a long time, can handle dry weather and floods, needs less herbicide and fertilizer, is easy to manage, and grows well in many different climates. In some warm, humid areas, it can produce a lot of plant material per hectare. Studies show that switchgrass gives back much more energy than it takes to grow. For example, for every unit of energy used to grow switchgrass, it can produce up to 20 units of energy! This is much better than many other crops used for fuel.

A lot of effort has gone into making switchgrass into ethanol fuel in the USA. In 2006, a former US President suggested using switchgrass for ethanol. Since then, a lot of money has been invested in this research. Switchgrass can produce a good amount of ethanol per tonne harvested. While corn ethanol currently yields more per tonne, switchgrass costs less to grow. This means switchgrass ethanol could be cheaper and produce more fuel per hectare.

Another great use for switchgrass is to burn it for heat. It can be pressed into fuel pellets, which are then burned in special stoves to heat homes. Switchgrass has also been tested as a replacement for coal in power plants. In some places, it's used to heat industrial buildings and farms. Burning switchgrass directly for heat is a very efficient way to get energy from it. Using switchgrass pellets can also help reduce greenhouse gases in the atmosphere.

Scientists are also studying how using switchgrass for ethanol affects the environment. They look at things like air and water pollution from growing and processing the grass. Studies suggest that using fuels with a high amount of ethanol from switchgrass can significantly reduce global warming potential compared to gasoline.

In 2014, scientists even created a special type of bacteria that can turn switchgrass into ethanol cheaply and efficiently.

Switchgrass growing tall

Switchgrass for Biodegradable Plastics

Scientists have found a new use for switchgrass: making biodegradable plastics. They have changed switchgrass plants so they can produce a material called polyhydroxybutyrate inside their cells. This material can be used to make plastics that break down naturally. While this is still a new idea, it shows the amazing potential of switchgrass.

Switchgrass for Healthy Soil

Switchgrass is excellent for keeping soil healthy and preventing it from washing or blowing away. It has a deep, strong root system that goes almost as deep as the plant is tall. These deep roots add a lot of rich organic matter to the soil. This is why the soils in the Midwestern United States, where switchgrass once grew widely, are so fertile today. By planting switchgrass, we can improve the quality of many soils, making them richer and better at absorbing water.

Because it grows tall, switchgrass can act as a barrier against wind erosion. Its strong roots also hold the soil in place, which helps prevent erosion from floods and runoff. Many highway departments use switchgrass in their seed mixes to plant along roadsides. It's also used on old mine sites and dams to help stabilize the soil.

Switchgrass for Animal Food

Switchgrass is a great food source for cattle, either as hay or for grazing. However, it can be harmful to horses, sheep, and goats. It contains natural chemicals called saponins that can cause skin problems and liver damage in these animals. Scientists are still learning more about this, so it's best not to feed switchgrass to horses, sheep, or goats.

When cattle graze on switchgrass, farmers need to manage it carefully. It's best to start grazing when the plants are about 50 centimeters (20 inches) tall and stop when they are eaten down to about 25 centimeters (10 inches). Then, the field needs to rest for 30-45 days to allow the grass to regrow. Switchgrass is most tasty and nutritious when it's young.

Switchgrass in Gardens

Many types of Panicum virgatum are grown as ornamental plants in gardens and for landscaping. Some popular varieties that have won awards for their beauty include 'Dallas Blues', 'Heavy Metal', 'Northwind', and 'Shenandoah'.

Special Switchgrass Varieties

Switchgrass has also been specially grown for use as animal food and for energy production. These varieties are chosen for traits like growing a lot of plant material, fast growth, deep roots, and being strong against tough weather. Varieties grown for animal food are easy for animals to digest and can grow in many different soils. Energy-specific varieties are designed to produce the most plant material for making renewable fuels. These special types of switchgrass help farmers earn more, especially when grown on land not suitable for other food crops.

See also

In Spanish: Pasto varilla para niños

• Algae fuel
• Backyard Wildlife Habitat
• Big Bluestem
• Butanol fuel
• Cellulosic ethanol
• Energy crop
• Natural landscaping
• Phytoremediation
• Wildlife garden