1. Switchgrass and Perennial
Grasses, Biomass, and Biofuels-
2012
Ken Vogel
USDA-ARS,Lincoln, NE

2. Main Conclusion
U.S. can displace over
30% of current
petroleum consumption
by 2030 using crop
residues and other
sources including
biomass from perennial
herbaceous crops for
the production of
cellulosic ethanol.
Emphasis on cellolosic
energy because of food
vs fuel problem.
http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf

3. 2007 Energy Independence and
Security Act (EISA)
• EISA requires EPA to revise the
Renewable Fuels Standards (RFS)
program to increase renewable fuel
blended into transportation fuel from 9
billion gallons in 1998 to 36 billion gallons
per year by 2022.
• Revised standards (RFS2) was finalized in
2010.

4. Renewable Fuel Standard
revised 2010 (RFS2)
• The RFS goal is 36 billion gallons per year
for renewable fuels by 2022.
• RFS2 limits the amount of corn ethanol
that counts toward the requirement to 15
million gallons per year.
• The remaining 21 billion gallons must
come from other non-food or cellulosic
sources
• Other sources are corn stover, perennial
grasses, woody biomass, and algae.

5. U.S. Billion-Ton Update 2011
• Increased emphasis
on dedicated energy
crops including
herbaceous
perennials such as
switchgrass, other
grasses and woody
species.
• Sustainable use of
crop residues.

6. Some Questions
• Why not just use corn stover?
• Why switchgrass?
• Why other perennial grasses?
• How are we going to get fuels out of this
stuff?
• Where are we at on management,
cultivars, and other improvements?

7. Long term Carbon sequestration Study-
Corn & Switchgrass, Mead, NE
• Quantify carbon
sequestration on cropland
converted to switchgrass.
• Compare to no-till corn.
• Experiment in eastern NE
established in 1998.
• In 2000, plots split and
stover removed (50%) on
split half of corn plots.

8. Corn Grain Yield – Effect of removing ½ of stover
Corn Grain Corn Grain after removal
25
½ stover removed
Grain Biomass (Mg/ha)
20
- 7.2% grain
15
10
5
0
2000 2001 2002 2003 2004 2005 2006 2007 Mean

9. Wally Wilhelm Gary Varvel

10. Factors Limiting Crop Biomass
Removal
Stover to retain (ton ac-1)
8
Soil organic carbon
6 Water erosion 5.58
Wind erosion
4 3.38 3.56 3.52
2.34
2 1.39
1.22
0.77 0.29 0.43
0.06 0.15
0
Moldboard No or Moldboard No or
plow conservation plow conservation
tillage tillage
Continuous corn Corn-soybean
Wilhelm et al., 2007. Agron. J. 99:1665-1667. ARS-REAP

11. Switchgrass Biomass Feedstock
Research
• 1980’s, : Oak Ridge National Laboratory, DOE, in
cooperative work with Universities & USDA-ARS.
Species evaluations. Selected switchgrass & hybrid
popular & willow.
• 1990’s, 2000-2002. Funded research at Univ. & ARS.
• 2002. DOE switchgrass work discontinued. All feedstock
and conversion research switched to corn stover and
crop residues.
• 2002 to present. New thrust by USDA-ARS. Perennial
energy crop research. A few land-grant universities
continue programs.
• 2006 – present. DOE renews major funding effort with
focus on basic biology & conversion. New USDA
funding. Private Companies funding inhouse research.

13. Why Switchgrass?
• Native to N. America • Low energy input
east of Rocky Mtns. • Increased carbon
• Adapted germplasm storage.
available. • Soil and water
• High yield potential conservation benefits.
• Can harvest and grow • Excellent wildlife
like hay using farm habitat.
equipment. • Buffer strips, wetlands
• Multiple uses on/off • Seed easy to plant
farm

14. Switchgrass
Panicum virgatum L.
Upland switchgrass plant Natural distribution of switchgrass
In North America

15. USDA-ARS Grain, Forage, &
Bioenergy Research Unit, Lincoln, NE
Switchgrass research
1930’s to present
• Native prairie species,
domestication, breeding &
management work to
revegetate grasslands after
drought of the 30’s
• Use by livestock was
emphasized
• 1990 - began work to
develop switchgrass into a
biofuel crop.
• 2000 - Information used for
farm scale production trials

16. Biomass Power
Back to the Future
• 1920 - 27,000,000
horses & mules,
USA
• 1954 - < 5,000,000
• Resulted in major
land use change.
• 80 million acres of
pasture & hayland
(biomass) released
for other uses.

17. Horse power to tractor power – land use changes,
government programs, & bioenergy
Fields in northeast Nebraska • Marginal land previously in
pasture converted to grain
crops. Severe erosion.
• Crop surpluses depressed
prices requiring farm
subsidizes
• Conservation Reserve Program
(CRP): over 35 million acres in
CRP.
• Annual cost is $1.7 billion.
Switchgrass field in same region • CRP land east of 100o W. Long.
could be used for perennial
biomass energy crops
(switchgrass).
• All conservation benefits would
be retained.
• Equivalent amount of marginal
cropland in USA.

18. Research Accomplishments
• Harvest management and timing
• Nitrogen fertilization rates
• Cultivar evaluations, classification, and
geographic adaptation
• Genetic improvements and new cultivar
development
• Genetic diversity and gene pools
• Production economics

19. Harvest Management
Vogel et al. (2002)
12
First cut
Biomass Yield (Mg/ha)
10
Second cut
8
6
4
2
0
1 2 3 4 5 6 7 8
Harvest interval (late June to late August)

20. Nitrogen Fertilization
Vogel et al. (2002)
11
Biomass Yield (Mg/ha)
10 Ames, IA
9
Mead, NE
8
7 Above this point, N application rate
exceeded N removal rate, increasing NO3-N
6 in the soil.
0 60 120 180 240 300
Nitrogen Applied (kg/ha)

21. Northern Plains Switchgrass Field Scale
Production & Economic Trials 2000-2005
15”-17”
Annual
2000-2005
Precipitation
On-Farm
Production
Trials:15-20 acre (6-
Cooperating farmers paid 9 ha) fields
to manage fields as biomass
energy crops.
31”-33”
Annual
Precipitation

22. DOE/USDA Biomass Feedstock
Stage Gate Review Meeting
March 14-16, 2005
• Improved Plant & Production
Practices for Grasslands &
Biomass Crops in the Mid-
Continental USA
Kenneth P. Vogel
USDA-ARS, Lincoln, NE

23. Plant Genomics for Biofuels"
BP-DOE Office of Science Review June/05
Ari Patrinos (DOE) & Steve Koonin (BP)
• Participants • Speakers
– Justin Adams, BP – Chris Somerville
– John Pierce, DuPont – Richard Flavell
– C. Saunders, Pioneer – Elliott Meyerowitz
– Don Doering, Winrock – Craig Venter
– Jim Barber, Metabolix – Jerry Tuscan
– Biotechnology Ind. Org. – Steve Straus
Reps. – Ed Buckler
– Other invited industry reps. – Ken Vogel
– USDA & DOE Senior – 4 others
Executives

24. Science editorial:
1/27/ 2006
Steve Koonin, BP
Chief Scientist
endorses biofuels
from cellulosic
sources such as
switchgrass.
Science 2006 cover story.
Tillman et al.
Science 2006 314:1598-
1600. Low input-high
diversity grasslands for
biofuels.

25. Switchgrass for Bioenergy – On farm
economic study in NE, SD, ND.
• Field shown at left had a five Switchgrass field in NE South Dakota
year cumulative average cost in 2005. Yields averaged 4T/acre.
of $33/T switchgrass biomass
including land & money costs.
• Average costs for 10 farms
was $60/T; two experienced
farmer’s costs were $39/T.
• Each big bale (left) represents
a 50 gal barrel of ethanol at
conversion rate of 0.38 L/kg
with average farm gate cost of
$0.64/gal. Low cost producers
= $0.53/gal at the farm gate.
Perrin et al. 2008 BioEnergy Research 1:91-98 (US units)

26. Take Home Lessons
• Economic production efficiency can be improved
via research and producer training.
• Adaptation and production trials in potential
biomass production areas are needed.
• Improved high yielding cultivars/hybrids with
improved conversion efficiency will be needed.
• Additional agronomic research on fertility,
establishment, seed quality, & other factors.
• Feedstock harvesting and storage research
needed.

27. Net energy and petroleum inputs from corn
and cellulosic (switchgrass) ethanol
(Ferrell et al. Science 2006 311:506-508)
Ignored co-products &
Used outdated
agronomics

28. Models over-estimate switchgrass
inputs
15
Estimated Inputs
Agricultural Inputs (GJ ha-1)
12
Actual farm
inputs from 5-yr
Other
9 USDA study
Machinery & Labor
Herbicide
6 Seed
Diesel
Fertilizer
3
0
Estab. Post. Farrell et al., Pimentel & Wang et al.,
2006 Patzek 2005 1999

29. On-farm Switchgrass Production in
the Great Plains – Net Energy
• Previous models over-estimated the
energy inputs for switchgrass
production by as much as 2X
• Switchgrass produced 13X more
energy as ethanol than was required
as energy from petroleum
• Switchgrass produced 540% more
renewable than non-renewable
energy consumed on marginal land
when properly managed
• Switchgrass biofuel production
systems are economically feasible,
environmentally sustainable, and
energetically positive on marginal
cropland in the central USA east of
the 100th Meridian
Schmer et al. 2008 – Proceedings of the National Academy of Science

30. Ethanol from switchgrass:
Input - output illustration.
Big round bale of
switchgrass – 0.7 ton
(0.63 Mg). Conversion
rate of 80 gal/ton (330
L/Mg)
Output Input
Net energy 8 gal.(30 L)
50 gal
(180 L)
Based on Schmer et al., 2008. PNAS105: 464-469.

31. Managed switchgrass produced 97%
more ethanol yield than man-made
prairies
USDA study Low yielding farms
4000
Mean yield
Ethanol Yield (L ha -1)
High yielding farms
3000
Tilman et al., 2006
2000
1000
0
Switchgrass LIHD LI-SW Corn grain
(Field-scale) (NGP)

32. Switchgrass grown for bioenergy:
Soil carbon storage in 5 years: 0-120 cm

33. Switchgrass Soil Carbon Sequestration
when grown and managed as a biomass
energy crop
• Field at left for period
Douglas, Nebraska Field
2000 to 2005
- 0 to 30 cm: 5 Mg
C/ha increase in soil
carbon (2.2 t/A)
- 0 to 120 cm: 18.4
Mg C/ha increase in
soil carbon (8.2 t/A)
(Liebig et al., Agron. J.
2008).

34. Coffee Break – Stretch Break
• After break topics
– Adaptation
– Yield
– Breeding & new cultivars
– Other species
– Conversion methods
– Biomass quality
– Improve Agronomic and Genetics

35. Ecoregions
Geographic regions for which thermal and
moisture (amount and season) determine
dominant plant populations.
Ecoregions of the USA

36. 1990 USDA Plant Hardiness Zones
growing season length, temperatures.

37. Plant Adaptation Regions of the USA
USDA Hardiness Zones
Vogel et al., 2005
Bailey’s Ecoregions

38. Target Plant Adaptation Regions
251-HZ 4&5 Prairie Parkland
332-HZ 4&5 Great Plains Steppe
331-HZ 4&5 Great Plains-Palouse Dry Steppe

39. Switchgrass Adaption
• Switchgrass is photoperiod sensitive (Benedict, 1941)
and is a determinate species.
• Photoperiod requirements are based on the latitude-of-
origin of individual ecotypes. Flowering is induced by
decreases in daylength following the summer solstice.
Photoperiod also affects winter sensence.
• When grown in the central Great Plains, switchgrasses
from the Dakotas (northern ecotypes) flower and mature
early and are short in stature while those from Texas and
Oklahoma (southern ecotypes) flower late and are tall
(Cornelius and Johnson 1941; McMillian 1959).

40. Switchgrass Adaption (cont.)
• In North America, moving northern ecotypes south
exposes them to a shorter-than-normal daylength during
summer month, which causes early flowering, reducing
biomass yield.
• The opposite occurs when southern ecotypes are
exported north. They remain vegetative for a longer
period of time, with a longer photosynthetically active
period, often producing more forage than northern
ecotypes (Newell, 1968).
• The physiological development of switchgrass as
determined by a maturity staging system is highly
correlated to Day of Year and Growing Degree Days with
DOY being the most important.

41. Switchgrass General Adaptation
Rule
• Switchgrass strains should not be exported more than
one USDA Plant Hardiness Zone north or south of their
area of origin for long term survival under biomass
production conditions.
• East-west adaptation is a function of disease resistance
(more humid conditions – more disease pressure) or
drought tolerance.
• Plant Adaption Region (PAR) of origin is a good indicator
or where switchgrass strain can be used. In current
environmental conditions, switchgrass strains can be
used in origin PAR and adjacent PAR. Some cultivars
have wider adaptation zones.

42. Revised USDA Plant Hardiness
Zone Map 2012

43. Plant Hardiness Zones have shifted
½ zone north since 1990
PHZ 4b
PHZ 5a

44. Adaptation and Breeding and
Management for Biomass Yield
• The easiest way to breed for improved biomass yield
is to use southern ecotypes to extend the effective
length of the pre-flowering growing season.
• Problem is winter survival. Plants need to move
storage carbohydrates to the roots for winter survival.
Because of photoperiod, southern ecotypes may start
this too late in northern latitudes and winter kill.
• Basic research on physiology and genetics of fall
sensence and spring green-up being conducted by G.
Sarath.
• If climate warming continues, it will affect adaptation
and also pathogen and insect populations.
• Regional trials are being used to track adaptation and
productivity.

45. Land required to produce feedstock for a 50 million
gallon (190 ML) cellulosic ethanol plant in a 25 mile
(40 km radius).
Feedstock Yield Acres (Mg/ha) % of Land Area
tons/acre (Mg/ha)
1 (2.2) 625,000 (250,000) 50
2 (4.5) 312,500 (125,000) 25
3 (6.7) 208,333 (85,000) 17
4 (9.0) 156,250 (63,000) 12
5 (11.2) 125,000 (50,000) 10
7.5 (16.8) 83,333 (34,000) 6.6
10 (22.4) 62,500 (25,000) 5
A 50 million gallon plant requires 625,000 tons (567,00 Mg) of feedstock/year at
80 gal/ton or 330 L/Mg conversion rate.

46. Breeding Progress for Conventional Switchgrass
Cultivars
Yield Trial Mead, NE 2003-2005
Cultivar Year released Biomass yield - IVDMD
Ton/a (Mg/ha) (%) (mature)
Trailblazer 1984 6.3 (14.1) 52.5
Shawnee 1995 6.5 (14.5) 54.8
NE Late YD 7.0 (15.7) 55.2
C4*

47. Improve biomass yields – hybrid
cultivars
Strain Yield
T/A
(Mg/ha)
Kanlow & 9.4 (21)
Summer
F1’s
Kanlow 7.1 (16)
Summer 6.1 (14)
• Improved hybrid cultivars with modified cell walls could
improve ethanol yields & reduce costs.

48. USDA switchgrass
study
10 locations
165 acres seeded
Seeded with
commercial drills Man-made prairies
Dryland sites One location
Harvested entire field Small-plots
with commercial hay
Hand-seeded
equipment
Irrigated during establishment
Hand-weeded
Hand-harvested using 4” strips
14% to 78% more annual
precipitation than USDA
switchgrass fields

49. Biomass Energy Crops for the Central USA
Switchgrass
• Perennial grasses such
as switchgrass and big
bluestem.
• Biomass sorghums.
• Corn stover
Big bluestem
Biomass Corn

50. Other Prairie Species with Biomass Energy
Potential
Illinois
‘Scout’ Indiangrass Bundleflower
PAR germplasm
releases
pending
Partridge Pea – germplasm
Big bluestem cv Goldmine release

51. Switchgrass seed – a principal attribute
• Switchgrass seed is easy
to harvest and plant.
• Seed yields can be high
400 to 1000 lbs/acre.
Seed cost less than for
other native species.
• Limited amounts (3-4.5
lbs PLS) needed to plant
a field.
• Other natives have chaffy
seed requiring special
processing and planters.

52. Biofuels from Biomass
Biological Conversion
Saccharification Fermentation Ethanol
Sugar Butanol
Perennial grasses Thermochemical Conversion
Lignocellulosic Biomass Fischer-
Gasification Synthesis Tropsch
gas Methanol
Crop residues Jet Fuel
Heat
Gasification
Power Gasoline
Pyrolysis Diesel
Bio-oil
Manure Hydrotreating-
Hydrocracking
Liquid Phase Chemical Processing
Saccharification Gasoline
Wood waste Sugar Liquid Phase Kerosene
Starch Processing Jet Fuel
Biological Catalytic
Liquid Phase
Glycerol Diesel
Thermochemical
Processing

53. Biological Conversion of Biomass
Lignocellulosic Biomass
Swithchgrass
Saccharification Fermentation Ethanol
Corn stover Sugar
Butanol
Manure
Status: Pilot plants are in operation, first full scale
biorefineries will go into operation next year using crop
residues and perennial grasses
Wood waste
Biological

54. Thermochemical Conversion of Biomass
Swithchgrass
Lignocellulosic Biomass
Fischer-
Gasification Synthesis Tropsch
Methanol
gas
Corn stover Heat Gasoline
Gasification Power
Diesel
Pyrolysis Deoxygenation Jet Fuel
Bio-oil
Hydrotreating-
Manure Hydrocracking
Status: Pilot plants in operation; Thermochemical
Some scale up next year. Several Catalytic
Wood waste
Companies with major funding:
CoolPlanet, LanzaTech, & others

55. Why fast pyrolysis?
Rapid thermal decomposition of
organic compounds in the absence
of oxygen to predominately produce
liquid product known as bio-oil.
Biochar
Co-product biochar
is produced at yields
of 12-20 wt%
Fast pyrolysis can be built at small biomass.
scales suitable for distributed
processing.
Bio-oil is refined like petroleum into
synthetic gasoline and biodiesel.

56. Biorefineries and Biomass
Feedstock Quality
ETO yield now about 330 L Mg-1
Potential yield = 450 L Mg-1.
(source: Nebraska Ethanol Board)

57. Genetic effects on lignin, anatomy & ethanol yield
from switchgrass cellulose
Thick, lignified layer
↓ Mean Ethanol Yield mg/g
80
78
Ethanol yield (mg/g)
76
Stem Lignin 63.2 g/kg
74
72
70
68
66
64
C-1 Hi Lig C-1 Lo Lig C+3 Hi Lig C+3 Lo Lig
Population
Stem Lignin 50.7 g/kg

58. Current switchgrass cultivars & agronomics
equivalent to 1960’s corn system
Switchgrass technology similar
to1960’s corn and Volkswagen
– a basic, good system with
improvement potential.
Corn yield improvement
50% genetic-50% agronomics

59. Bottom Line
• Switchgrass is an economically feasible
biomass energy crop for use on marginal
cropland.
• Improvements in genetics and agronomics
will improve:
– biomass yields
– biomass quality
– conversion
– ethanol or biocrude yield per acre

60. Conversion information
Biomass to ethanol Corn grain to ethanol
80 gallon/US ton 2.5 to 2.9
(Current technology) gallon/bushel
110 gal/ton potential. Feedstock cost per
Feedstock cost per gallon
gallon $ bushel/2.9 gal.
$ton/80 gal. $2.50 bu/ 2.9 gal
$40 ton/ 80 gal = $0.50 =$0.86/gallon
gallon feedstock cost. feedstock cost.
$3.50 bu = $1.21/gal
cost.