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Oklahoma Prairie Country

~Prairie Grasses~

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     Big Bluestem
     Little Bluestem
     Indian Grass
     Switchgrass
     Prairie Cordgrass
     Japanese Brome
     Fish-on-a-Fishing-Pole Grass
     Hairy Grama
     Canada Wild Rye
     Biofuels

   The center of the United States has been blessed with a sea of grasslands. The bad news is that less than ten percent of the prairies that existed 500 years ago still exists. Grasslands from the Canadian border to the Gulf of Mexico have fallen victim to land development, housing, malls, and farming. Fortunately organizations like The Nature Conservancy are making an effort to protect what is left of these grassland areas. For instance, the Tallgrass Prairie Preserve in northeastern Oklahoma is the largest contiguous tallgrass area in existence. It is an area of about 39,000 acres situated at the southern edge of the Flint Hills.

   Oklahoma is fortunate in having the three types of prairie within its border. The eastern section is composed of tallgrass, the center section is mixed grass, and the western area is short grass prairie. Don't come to the eastern prairies and expect to see 6-10 ft. grass in the spring or early summer. It takes a full growing season to reach those heights. The height of mature grasses depends also upon the rainfall and when that rainfall occurs. What defines a tallgrass prairie as far as height of the grass? If the conditions are less than ideal and the grasses only reach knee high, the prairie is still considered a tallgrass prairie. This often disappoints some of our visitors, but, believe it or not, there are some aspects of nature that we do not control.

   On our tallgrass prairie here in Oklahoma there are several grasses which predominate. Important species are Big Bluestem, Little Bluestem, Indian Grass (the Oklahoma state grass), Switch Grass, and Prairie Cordgrass. The tallest of the grasses, especially when the summer season is blessed with adequate rainfall, is the Big Bluestem. The Little Bluestem is beautiful in the fall with a summer setting sun as a backdrop. Here is some information about the different grasses.


Big Bluestem, Andropogon gerardii

   The Big Bluestem is a majestic grass, able to grow ten feet tall. It is clear why it received the name "Bluestem" if you see it in mid growth. The main stem is a definite blue-green color. The seed head branches into three segments, which prompted some people to call it turkey foot grass. Big Bluestem grows from large clumps and produces many leaves. The root system is very dense and may extend ten feet into the soil. It was the perfect material for making "bricks" for the building of sod houses.

   Big Bluestem is a very important nutritious forage crop. Cattle and bison relish the immature green leaves in spring and early summer. Just as with other grasses the Big Bluestem will slowly disappear from a prairie if the grass is repeatedly grazed to eight inches or less during a growing season.

   The Big Bluestem starts its growth in early April and matures by September. The leaves are up to two feet long and less than half an inch wide. The leaves begin their growth rolled into a tube and unroll as they grow. The flowers are at the end of tall stalks and form three clusters from a common point. The leaves turn a reddish color after frost.

Image of Big Bluestem    This is a picture of Big Bluestem as it is in mid July. The color of the main stem is blue-green. The grass is 4 to 6 feet tall already due to the adequate rainfall this spring and early summer.
(Click on the picture for a larger view)






Image of Big Bluestem        This picture was taken in mid August when the Big Bluestem is beginning to mature and is near its maximum height.






Little Bluestem, Andropogon scoporius

Image of Little Bluestem    
   Little Bluestem is a warm season perennial grass that grows up to four feet tall. It grows in dense clusters with a root system that goes down 5 to 8 feet. The leaves, like the Big Bluestem, emerge from the stem folded and unfold as they grow to twelve inches in length and less than one-fourth inch wide. The main stems are hairy and flat near the base. The flowers of the Little Bluestem are scattered along the upper parts of the stems and have a feathery appearance. In the fall the plants turn a reddish color and sport white, feathery flowers.

   Little Bluestem is the most widely distributed grass. it is found in all but four states. It is considered the most important grass in Oklahoma and Kansas because of its nutritive value to cattle.



Indian Grass, Sorghastrum nutans

Image of Indian Grass    
   Indian Grass is another important plant on the prairie. It is nutritious and is eaten by all types of livestock. It grows in clumps or as single stalks. Leaves are up to two feet in length and less than one half inch wide. Indian Grass can be identified by a pair of tooth-like, pointed lobes where the leaf meets the stem. It grows from rhizomes and is blue-green in color.The seed heads form attractive plumes at the top of the stems. It is found in all counties of Oklahoma and is designated as the state grass. It is an important source for hay. The plants provide good cover for small mammals.


Switchgrass, Panicum virgatum

   Switchgrass is another warm-season grass with bluish- green leaves. It grows three to six feet tall. Propagation is by seed and by underground stems. Leaves are one-fourth to one-half inch wide and six to eight inches long. Identification can be made by observing a dense tuft of hairs at the upper surface of leaves where they join the stems. The seed head is made up of a large cluster of slender stems with the tiny flower buds on the ends. Switchgrass is a very nutritious forage crop and is eaten by all types of livestock. It produces good hay if cut before maturity. As the plant mattures it loses nutrient content. When food is scarce the deer will eat the rhizomes. Horses tend to avoid the grass.


Japanese Brome, Bromus japonicus

Image of Japanese Brome    
   The photo may be a varient of Japanese Brome. This is an annual. It grows 1-5 ft. tall, errect or curving. Leaves are 2-5 in. long. It's sheaths have small hairs usually pointing downard. It is an introduced species from Eurasia. It germinates in the fall, grows in the winter, and flowers in late spring. Wildlife and livestock may eat it, but its importance is considered low. Following fall rains germination is prolific and seedlings carpet the ground. It is found throughout Oklahoma.



Fish-on-a-Fishing-Pole Grass, Chasmanthium latifolium

Image of Fish-on-a-Fishing-Pole    
   This is a perennial from rhizomes. It is also known as Broadleaf Uniola. Leaves are 3/16 to 0.5-in. wide and 0.5 to 2-in. long. Growth is in clonal form. This grass is usually under canopies of trees. It may be grazed by cattle, but is not important forage. New growth following a fire is near Big and Little Bluestem in protein content.



Hairy Grama, Boutelouna hirsuta
    
   Hairy Grama is a native species warm-season grass. It grows 10 to 18 inches in height. The slender stems eminate from its base. Leaves are hairy on the edges and upper surface. It is a tufted bunchgrass. The seed heads, usually 2, are born on leafless stalks. The seed spikes are covered with hair and end with a needle-like point.



Canada Wild Rye, Elymus candensis

Image of Canada Wild Rye    
   This is a cool-season, rhizomatous grass. It grows 2 to 4 feet tall. Wild Rye is recognized by its nodding spikes and long awns. It begins growth in the fall, ceases in the winter, then begins again in spring. It flowers in early summer. Wild Rye is eaten by livestock in its early stages, but its value decreases as it ages.



Prairie Cordgrass, Spartina pectinata

   Prairie Cordgrass is a tall grass growing up to ten feet tall. The leaves are twelve to thirty inches long and about one-half inch wide. The edges of the leaves have short sharp teeth. Each stem is topped by a cluster of up to 32 side branches, each of which is 1.5 to 6 inches long and covered with numerous straw-colored flowers. The grass propagates by seed and heavy, woody, creeping rhizomes. The grass is also known as Slough Grass or Ripgut, since the rough blade margins can cut flesh readily.. Livestock graze on the plants when new and tender, but as a mature grass it is less palatable. It can be cut for hay when young. The tall dense stand of the grass provides good cover for birds.



Biofuels
    Alternative fuels are becoming more important with the general thrust being to relieve the country's dependence upon foreign oil. We can not satisfy this country's appetite for energy from "local" oil reserves and from coal deposits. The total amount of petroleum in the earth is finite and can not be replenished. The push for less air pollution adds another dimension to the search for cleaner alternative fuels.

   Research has been going on in many laboratories across the country, including Oklahoma State University, to find the "plentiful, economic, and clean biofuel." The use of a blend of ethanol and petrofuel is well known and is available in parts of the country. The problem with such a blend, which produces less pollution, is how do we produce the ethanol. Presently it is made mostly from corn and grain sorghum. That means that there is competition for the corn as a food source and a fuel source, not to mention the production of "drinking spirits."

   It makes sense that we should be searching for renewable fuel sources. Biomass is a logical solution since it can be used as a combustible fuel as well as a raw material for production of a biofuel, such as ethanol. Another advantage is that biofuel uses carbon dioxide from the air during it's growing cycle, so one can say that carbon dioxide is recycled.

   Switch grass (Panicum vergatim) is a warm season perennial grass that grows throughout prairie country as far north as Canada. It is easily seeded and can be harvested with a combine. Solid pellets of the dried grass can be used as a combustible fuel.

   To produce ethanol the grass has to be mechanically or chemically broken down. Enzymes can be used to break it down further into glucose and pentose molecules. A fermentation process then produces alcohol from the mass and the ethanol is collected by distillation.

   According to the Oak Ridge National Laboratory 20 pounds of dry switchgrass can produce 1 gallon of ethanol, which weighs 6.59 pounds.

   Not all researchers are touting biofuels. David Pimentel, professor of ecology and agriculture at Cornell, concludes that there is no energy benefit in using biomass for liquid fuel. He made a study of the total fuel energy required to produce liquid biofuel. He took into consideration the energy required for producing pesticides, fertilizer, running machinery, irrigating, grinding, transportation, and distillation. With all these factored in he concluded the following:

      > corn requires 26% more fossil energy than the fuel produced;
      > switch grass requires 45% more fossil energy than fuel produced;
      > wood requires 57% more fossil energy than the fuel produced;
      > soybean plants require 27% more fossil energy than fuel produced.

It is not evident whether he estimated the amount of fossil fuel needed to produce the fossil fuel.

   The energy output/input for producing alcohol from corn is 1.2. The net gain from corn ethanol is 21%. The energy output/input ratio for ethanol from switch grass is 4.4, or a net energy gain of 334%. Researchers now are looking for special species of grasses that may give higher yields of alcohol. Switchgrass is a good start!





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Copyright 2004 by Van Vives.
Photos by Van Vives. Request permission before using.
This page was updated 4/28/2015.