Switchgrass as a Biofuel in the Chariton Valley, Iowa Agronomic Considerations

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Switchgrass as a Biofuel in the Chariton Valley,
Iowa Agronomic Considerations

• Lee Burras, Charlie Brummer, Marty Braster, John
  Sellers, Mike Barker
• Iowa State University Chariton Valley RCD
• ORNL BFDP Cooperators Meeting, Memphis
• November 07, 2001

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Outline

• Objectives
• Site overview
• Review of project significant conclusions
• How ready are we to produce switchgrass?
• Summary
• As questions come up, please ask.

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General Research Objectives

• 1997 onward
• Identify/develop SWG cultivars suitable for
  biofuels and adapted to south-central Iowa.
• Examine SWG yield at the field level.
• Examine SWG impact on soil quality.
• Part of a scale-up project that includes
  upgrading the Ottumwa Generating Station and
  burning of 4000 tons of SWG. See
  http//www.cvrcd.org.
• 2000 onward
• Do the same for reed canary grass (RCG)

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Who does and has done the real work for ISU?

• Mike Barker Research Associate, ISU
• Julie McLaughlin Research Associate, ISU
• Rocky Lemus PhD student, VA Tech
• Neil Molstad SDI Consulting, Oak Brook, IL

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Overview of site soils weather
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Landscape Characteristics of the Chariton Valley
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Relative agronomic productivity across Iowa ( CSR
values given)
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Objective 1 Identify SWG cultivars suitable for
biofuels and adapted to SC Iowa.

• Ongoing evaluation of 20 SWG cultivars planted in
  1997.
• Plot study randomized complete blocks w/ 8
  replications.
• Plot size 3.0 4.6 m
• Spring N _at_ 78 kg ha-1.
• Biomass yield (fall harvest).
• Laboratory fiber, total N, Ash, Cl, P, S,
  etc.

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Results - SWG cultivars suitable for biofuels and
adapted to SC Iowa (small plots).

• Yields highly variable.
• Yields improved from 1998 to 1999 (6.4 Mg ha-1
  and 11.8 Mg ha-1, respectively).
• No 2000 yields b/c wet fall then snow.
• Highest lowland varieties (Alamo 17 Mg ha-1
  Kanlow 16 Mg ha-1) some uplands 15 .
• Higher yields seem possible and likely.
• Caution cold, snowless winter impact on lowland
  varieties?

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Results - SWG cultivars suitable for biofuels and
adapted to SC Iowa (small plots).

• Varieties average comparable ADF (47), ADL (6)
  and ash contents (5), respectively.
• Varieties differ in height (150-220 cm), NDF
  (80), N (0.4-0.6) and IVDMD (23-30)

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Results - SWG cultivars suitable for biofuels and
adapted to SC Iowa (small plots).

• Chemical compositions all ok for co-firing.
• Reduction in Cl, P, and S occur between November
  March.
• Lodging disease ? all varieties.
• Spring harvest?
• Co-selecting for yield and biofuel quality seems
  reasonable.

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Objective 2 SWG yields at the field level.

• Two approaches
• --- four ISU managed fields (N fertility
  landscape positions), yields from 1998, 1999,
  2000.
• --- Farmer fields - farmer harvests.,
• data from 45 strips 12 fields, just 1999 data
  currently. All strips 112 kg N and atrazine weed
  control.

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ISU field set up
0
112
224
56
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Results SWG yields in four ISU managed fields.

• theses for Rocky Lemus Neil Molstad, now Mike
  Barker.
• Mean yields of 3, 4, and 6 Mg ha-1 for 1998,
  1999, 2000, respectively.
• Appropriate N is 60 to 100 kg ha-1 yr-1.
• Summits highest yielding.
• Cell wall characteristics do not vary much by
  year, location, or fertility.
• Overwintering SWG in the field improves biofuel
  characteristics but at big yield loss.

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Farmer yields

• Average was 6.5 Mg ha-1 w/ range being 3 to 16 Mg
  ha-1.
• Yield is proportional to CSR. Best soils are
  loess-derived (summits) poorest soils are
  paleosols (backslopes).

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Objective 3 SWG soil quality

• OC ranges from 5 to 34 kg m-3 PasturesgtSWGgtRow
  Crop.
• Upland OC ratios are 0.5-0.8-1.0 for
  20cm-50cm-100cm, respectively.
• Least OC is on BS (where most erosion lowest
  yields are).
• Gullies common big problem
• SWG promotes stable aggregates thickening of A
  horizon.

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So, how ready are we to really grow SWG?
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How ready are we to produce switchgrass?

• We can produce switchgrass in an environmentally
  benign fashion.
• But we need to manage for all types of water
  erosion. Backslopes are the problem. And we
  need more knowledge on nitrates and off farm
  impacts.
• We can produce switchgrass having meaningful
  agronomic yields (6 Mg ha-1). In fact, my guess
  is we could double or triple yields on better
  ground.
• But this may negate beneficial impacts desired
  for fragile lands in the area. It may also shift
  production to the higher CSR ground away from
  Ottumwa.
• We can produce switchgrass in a manner beneficial
  to the rural economy of Iowa.

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How much time do we need?

• It depends. How much SWG do we want? We are
  producing a few thousand tons per year now.
• If we want a lot more we need two to three years
  lead time

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Questions Comments?