Growing Grass for Energy

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Growing Grass for Energy

• Vance N. Owens
• South Dakota State University

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What is Lignocellulosic Biomass?

• Biomass is all plant and plant-derived materials
  including animal manure.
• Lignocellulosic biomass is the nonstarch, fibrous
  part of plant materials, woody, and generally
  inedible portions of plant matter.

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Potential Biomass Resources

• Crop residues (e.g., corn stover, wheat straw)
• Grain (e.g., corn, canola)
• Woody crops (e.g., hybrid poplar)
• Forest resources
• Other agricultural waste(e.g., manure)
• Perennial grasses (switchgrass, big bluestem,
  prairie cordgrass, etc.)

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Why Perennial Grass for Biomass?

• Advantages
• Reduced fuel, pesticides, and fertilizer
• Grown on land not suitable for annual crops
• Soil and water conservation/quality
• Carbon sequestration/reduce global warming
• Wildlife habitat
• Issues
• Harvest, storage, and transportation
• Processing
• Pretreatment

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Key Attributes of Promising Perennial Energy Crops

• Native or noninvasive
• High biomass yield potential
• Established with seed or relatively inexpensive
  vegetative propagules
• High nutrient and water use efficiency
• Broad genetic variability
• Persistent
• Harvestable with standard agricultural equipment
• Environmental benefits

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Switchgrass

• Native, warm-season, perennial
• Eastern 2/3 of North America
• Tall grass prairie from Canada to Central America
• Extensive genetic variation related to latitude
• Relatively easy to establish good seed producer
• Long-lived sod-former
• Resistant to lodging
• Wildlife habitat

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Switchgrass biomass left standing over winter
traps snow and provides cover for wildlife
December 1, 2005 Brookings, SD
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Switchgrass Biomass After Snow Melt March 30, 2006
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Switchgrass managed for biomass production
provides habitat for white-tailed deer,
pheasants, and other wildlife
October 2004 Dakota Lakes Research Farm Near
Pierre, SD
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Native grass monocultures and mixtures

• Monoculture stands of switchgrass, big bluestem,
  and indiangrass versus two- and three-way
  mixtures of these species

Switchgrass
Big bluestem
Indiangrass
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Big bluestem

• Greens up later than switchgrass
• Dominant species of tallgrass prairie
• Excellent quality and highly palatable
• Leaf growth/soil cover

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Indiangrass

• Prominent species in tallgrass prairie
• Excellent quality if grazed/hayed before heading
• Good wildlife habitat
• Persistence may be an issue in northern Great
  Plains

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Switchgrass/big bluestem mix
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Prairie cordgrass

• Tall growing
• Native C4 grass
• Low, wet areas
• High yield potential
• Forage
• Biomass energy
• Season-long growth
• Widely distributed

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Why prairie cordgrass?
Season-long growth
Widely adapted
Source U.S. Department of Energy Genome Programs
(http//genomics.energy.gov.)
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Prairie cordgrass adaptation to marginal land
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Prairie cordgrass on the landscape
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Prairie cordgrass growth habit (Fall 2008)
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Prairie cordgrass management and production

• Seeding and establishment
• Seeding rate
• Equipment
• Seed treatment
• Seeding time
• Management
• Fertilizer
• Chemicals
• Harvest time
• Persistence

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Prairie cordgrass yield potential
Source Arvid Boe
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Prairie cordgrass response to N (Locken Farms, 29
Oct. 2008)
NS
NS
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Prairie cordgrass harvest (Locken Farms, 29 Oct.
2008)
North Unit
South Unit
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Biomass Work in South Dakota

• Harvest management of long-established
  switchgrass and mixed stands enrolled in or
  managed similarly to CRP

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Effect of harvest timing (anthesis and killing
frost) and harvest frequency (every year and
alternate years) on total and switchgrass biomass
production in Gregory Co., SD for 2001-2002 and
2003-2004 growth cycles.
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Harvest Timing Effect on Switchgrass
Persistence(Moody County, South Dakota)
Harvested in August 2001-2004
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Harvest Timing Effect on Switchgrass
Persistence(Near Pierre, South Dakota)
Dakota Lakes, Aug. 6, 2006
Harvested in March or April 2001-2005
Harvested in July 2000-2005
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Other On-going Biomass Work at SDSU

• Species comparisons (switchgrass, big bluestem,
  and intermediate wheatgrass)
• Harvest management (forage, biomass-fall, and
  biomass-spring)
• Landscape position (backslope and footslope)
• Manure application
• Seed production

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Summary

• Conversion
• Financial support from US DOE should help
  companies demonstrate commercial potential of
  biomass to biofuel
• The Biorefinery Concept integrates biomass
  conversion processes
• Production
• Mixtures of perennial grasses may provide
  environmental benefits but switchgrass helped
  maintain yields
• Native grasses such as switchgrass and prairie
  cordgrass utilize N efficiently
• Proper harvest timing is critical for sustainable
  production of switchgrass
• Certain species may allow for winter carryover
  better than others
• All biomass is local

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Questions