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As a leader in bioenergy research and development, the Noble Foundation is evaluating the agronomics and economics of switchgrass as a bioenergy crop. Switchgrass is a native range and pasture grass that has been identified by state and national leaders as a potential crop to be grown, harvested and converted into ethanol. Slow seedling establishment has previously limited adoption of switchgrass in forage production. Presently, scientists in the Noble Foundation's Agricultural and Forage Improvement divisions are researching ways to improve switchgrass establishment. Here is what we know, and don't know, about the process. Switchgrass planting at the Noble Foundation Dupy farm Seed Selection and Quality When choosing a variety, it is important to purchase high quality, certified seed. Freshly harvested seed can have a high percentage of dormancy. Seed dormancy is typically reduced if the seed is properly aged for one year. Seed older than two years may become less viable and have poor seedling vigor under field conditions. Check with seed companies on availability and quality of their seed before making purchases. Planting Date and Methods Planting methods include drilling or broadcasting into either tilled or no-tilled seedbeds. Drilling involves planting in rows using either a conventional or no-till drill. Broadcast seeding refers to techniques where seed is spread uniformly across the soil surface. Regardless of method, switchgrass should be planted at shallow depths, 0.25 to 0.5 inches, in seedbeds that are firm enough to allow good seed-to-soil contact, but not so much as to restrict root growth. Research shows that switchgrass produces similar yields across a range of seeding rates and row spacings. At lower plant population densities, individual plants are able to exploit more space and soil resources, attain greater size and maintain biomass yields equivalent to those grown at higher plant population densities. Recommended seeding rates of switchgrass range from two to 10 pounds of pure live seed (PLS) per acre, with the higher rates applied to sites with poorer growing conditions. Generally, four pounds PLS per acre is sufficient. Second year stands of one to 1.5 plants per square foot (43,000 to 65,000 plants per acre or more) would be considered fully successful stands. Stands with less than 0.5 plants per square foot (22,000 plants per acre) may require partial reseeding to maximize biomass yields. Soil Fertility and Weed Control |
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© 1997-2008 by The Samuel Roberts Noble Foundation, Inc.
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