Crop Residue as Feedstock for the New Bioeconomy: Opportunities and Roadblocks

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Crop Residue as Feedstock for the New
BioeconomyOpportunities and Roadblocks

• W. W. Wilhelm USDA-ARS, Lincoln, Nebraska
• G. E. Varvel USDA-ARS, Lincoln, Nebraska
• D. L. Karlen USDA-ARS, Ames, Iowa
• J. M.-F. Johnson USDA-ARS, Morris, Minnesota
• J. M. Baker USDA-ARS, St. Paul, Minnesota

CSSA Symposium Feedstock Production for the New
Bioeconomy Opportunities and Roadblocks Crop
Science Society of American Annual Meeting,
Indianapolis, Indiana November 14, 2006
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Billion Ton Report

• Biomass production 1366 million ton
• Forestry 368 million tons
• Agriculture 998 million tons
• Perennial energy crops 377 million tons
• Wastes 87 million tons
• Grain 87 million tons
• Crop residues 428 million tons
• Corn stover 256 million ton

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Billion Ton Report

• Biomass production 1366 million ton
• Forestry 368 million tons
• Agriculture 998 million tons
• Perennial energy crops 377 million tons
• Wastes 87 million tons
• Grain 87 million tons
• Crop residues 428 million tons
• Corn stover 256 million ton

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Bold, optimistic projections Basis for
discussion Lofty target
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What is a ONE BILLION?

• If one ton 1 sq in
• 1 billion tons 145 football fields

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What is a ONE BILLION?

• If one ton 1 sq in
• 1 billion tons 145 football fields
• Agricultural land (cropland plus hay and pasture)
• 5 ton ac-1
• 200 x 106 acres
• 56 of North Central Region agricultural land
• Iowa, Illinois, Nebraska, Minnesota, Indiana, and
  South Dakota (Total 195.5 x 106 ac)

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Billion Ton ReportAgriculture Assumptions

• Yield increase 50 by 2030
• Corn and small grains
• Residue/grain ratio for soybean increase from
  1.51 to 2.01
• Machine to recover 75 stover
• No tillage adopted universally

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Corn yield Nebraska contest winners and averages
Duvick and Cassman. 1999. Crop Sci.
391622-1630. Cassman et al. 2003. Ann. Rev.
Envir. Res. 28-315-356.
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Cassman et al. 2006. CAST Report (release Nov.
16, 2006)
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Billion Ton ReportAgriculture Assumptions

• Yield increase 50 by 2030
• Corn and small grains
• Residue/grain ratio for soybean increase from
  1.51 to 2.01
• Machine to recover 75 stover
• No tillage adopted universally

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Residuegrain in soybean

• Low residue production
• Longevity of residue
• Accelerates decay of SOM
• Greater N content of leaves and roots
• Rhizodeposits
• Large biomass soybean (LBS)
• Forage-type soybean
• Grain yield not proven
• Grain harvest efficiency

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Billion Ton ReportAgriculture Assumptions

• Yield increase 50 by 2030
• Corn and small grains
• Residue/grain ratio for soybean increase from
  1.51 to 2.01
• Machine to recover 75 stover
• No tillage adopted universally

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Fractional stover harvestISU proto-type harvester
Harvest scenario Stover collected(Mg ha-1) Percentharvested ()
High cut (at ear height) 4.9 46
Low cut (header on soil) 6.7 64
Normal cut 5.1 49
Total residue produced, 10.5 Mg ha-1
Hoskinson et al. 2006. Biomass and Bioenergy (in
press).
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Billion Ton ReportAgriculture Assumptions

• Yield increase 50 by 2030
• Corn and small grains
• Residue/grain ratio for soybean increase from
  1.51 to 2.01
• Machine to recover 75 stover
• No tillage adopted universally

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No tillage adoption(Conservation Tillage
Information Center-National Crop Residue
Management Survey, 1994-2004, http//lanshark.ctic
.purdue.edu/CTIC/CRM.html)
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No till with no residue

• Runoff occurred sooner
• Significant carryover effect of residue removal
• Runoff initiated 35 sooner in subsequent year
• Sediment concentrations increasing by gt 100.

Wilson et al. 2004. Trans. ASAE 47119-128.
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Billion Ton ReportAgriculture Assumptions
Assumption Assessment
Yield increase 50 by 2030 Doubtful
Residuegrain ratio for soybean increase from 1.51 to 2.01 Achievable, but of doubtful use
Machine to recover 75 stover Very achievable
No tillage adopted universally Doubtful
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Traditional uses of crop residues
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Soil C change
No tillage Cover crops Green manure
Pre-cultivation steady-state
REAP
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Residue needed to maintain SOC
Crop rotation Tillage Mg ha-1 n
Corn mbp 7.51.0 6
Wheat mbp 5.51.1 5
All mbp 6.31.0 13
All Chisel/nt 4.50.4 5
REAP
Johnson et al. 2006. Agron. J. 98622-636.
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Change allocation of biomass
REAP
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Change allocation of biomass
REAP
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Change allocation of biomass vs. increase total
biomass production
Increase photosynthetic efficiency 25, from 4 ?
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REAP
Long et al. 2006. Plant Cell Envir. 29315-330.
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Multiple biomass Many technologies Conservation Re
duced expectations Asking and answering the right
question