Going Green

Thursday, January 24, 2008

Ethanol From Switchgrass

Ethanol: Depending upon where you fit in agriculture, ethanol is either a dirty word or the best thing that has come along in years. Livestock producers curse it because of its impact on their cost of feed, but farmers love the extra dollars that it has put into their pockets. Ideally, a way for both segments of agriculture to benefit from ethanol will be found. Perhaps the answer is Switchgrass.

Switchgrass is a perennial grass found in almost every state west of the Rocky Mountains. There are two major classifications of the grass: 1) upland varieties which favor drier, lighter soils and fare better in drier conditions and 2) lowland varieties which thrive in heavier soils and are tolerant of excess moisture such as from flooding.

Switchgrass has been neglected by researchers for many years but now, because of its promise as an energy fuel, they are scrambling all across the nation to collect samples of the various native species so that cultivars can be developed to breed for fuel production. Such efforts are occurring at experiment stations from Texas to the Dakotas and throughout the Midwestern and Southeastern U.S.

Producing ethanol from Switchgrass falls into the category of what is considered cellulosic ethanol. This category is still in the developmental stage but shows great promise of utilizing everything from waste paper pulp to wood chips and grasses. It is a more complex process than producing ethanol from corn, but shows great potential because it can utilize waste, or plant sources grown on marginal land rather than corn which requires premium land and an abundant supply of water as well as intensive use of chemical and fertilizer inputs.

Recent research indicates that corn-based ethanol produces approximately 125% more energy than is required to make it. The potential energy from Switchgrass has been estimated at 540% more than that required to produce it. In addition to the huge energy gain, the amount of inputs required to grow Switchgrass is relatively low and it is a perennial crop.

Switchgrass grows well in regions that receive between 15 and 30 inches of rainfall per year and thrives in a wide variety of soils ranging from fine to coarse in texture. Its roots produce rhizomes that spread beneath the soil surface and will cover approximately the same area below ground that the plant covers above ground. The plants can reach up to 10 feet in height if adequate moisture is available at the right time of year.

In order to produce maximum yields, Switchgrass may require some supplementation of nitrogen. It can be difficult to establish because of low germination rates due to a high percentage of dormancy, but once established, is a perennial producer. Depending on growing conditions, it may produce anywhere from one to three cuttings per year. If a single cutting per year is all that is harvested, the plant has the characteristic that most of the primary nutrients migrate back into the roots in late summer and early fall. If harvest is delayed until after frost, very little of the soil nutrients will be removed with the harvested crop.

As cellulosic ethanol technology develops, Switchgrass will become an important fuel source. Because of its low input requirements, it may hold promise as a significant cash crop for marginal land. The development of new varieties that accommodate the diverse growing conditions across the United States will create opportunities for farmers in many areas. It also appears to hold promise in some areas of the Texas Panhandle – particularly the eastern part of the area where rainfall is generally slightly higher.

Because it typically takes approximately 3 years to establish a harvestable stand of Switchgrass, the decision to produce the crop will require considerable planning. It obviously will not fit into a rotation plan but will fit best on dedicated acres. Over the coming years it is anticipated that some CRP acres may be converted to the crop. Ultimately, the price offered for baled Switchgrass will determine the planted acreage.

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