1. Crop Residue as Feedstock for the New Bioeconomy: Opportunities and Roadblocks W. W. WilhelmUSDA-ARS, Lincoln, Nebraska G. E. VarvelUSDA-ARS, Lincoln, Nebraska D. L. KarlenUSDA-ARS, Ames, Iowa J. M.-F. JohnsonUSDA-ARS, Morris, Minnesota J. M. BakerUSDA-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

2. 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

3. 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

4. Bold, optimistic projections Basis for discussion Lofty target

5. What is a ONE BILLION? If one ton = 1 sq in 1 billion tons = 145 football fields

6. 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 10 6 acres 56% of North Central Region agricultural land Iowa, Illinois, Nebraska, Minnesota, Indiana, and South Dakota (Total = 195.5 x 10 6 ac)

7. Billion Ton Report Agriculture Assumptions Yield increase 50% by 2030 Corn and small grains Residue/grain ratio for soybean increase from 1.5:1 to 2.0:1 Machine to recover 75% stover No tillage adopted universally

8. Corn yield Nebraska contest winners and averages Duvick and Cassman. 1999. Crop Sci. 39:1622-1630. Cassman et al. 2003. Ann. Rev. Envir. Res. 28:-315-356. 19651975198519952005 Corn yield (Mg ha -1 ) 0 5 10 15 20 25 Corn yield (bu ac -1 ) 0 50 100 150 200 250 300 350 Irrigated average 114 kg ha -1 yr -1 (1.81 bu ac -1 yr -1 ) Irrigated contest winners Rainfed contest winners 208 kg ha -1 yr -1 (3.31 bu ac -1 yr -1 ) Rainfed average 89 kg ha -1 yr -1 (1.42 bu ac -1 yr -1 )

9. Cassman et al. 2006. CAST Report (release Nov. 16, 2006) Double-X to single-X hybrids Expansion of irrigated area, increased N fertilizer rates Conservation tillage, soil testing, NPK fertilization Transgenic (Bt) insect resistance Reduced N fertilizer & irrigation? (embodied technological innovation) Integrated pest management USA Corn Yield Trends, 1966-2005 y = 112.4 kg ha -1 yr -1 (1.79 bu ac -1 yr -1 ) r 2 = 0.80 2000 4000 6000 8000 10000 12000 196519701975198019851990199520002005 Year Grain yield (kg ha -1 )

10. Billion Ton Report Agriculture Assumptions Yield increase 50% by 2030 Corn and small grains Residue/grain ratio for soybean increase from 1.5:1 to 2.0:1 Machine to recover 75% stover No tillage adopted universally

11. Residue:grain 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

12. Billion Ton Report Agriculture Assumptions Yield increase 50% by 2030 Corn and small grains Residue/grain ratio for soybean increase from 1.5:1 to 2.0:1 Machine to recover 75% stover No tillage adopted universally

13. Fractional stover harvest ISU proto-type harvester Hoskinson et al. 2006. Biomass and Bioenergy (in press). Harvest scenarioStover collected (Mg ha -1 ) Percent harvested* (%) High cut (at ear height) 4.946 Low cut (header on soil) 6.764 Normal cut5.149 * Total residue produced, 10.5 Mg ha -1

14. Billion Ton Report Agriculture Assumptions Yield increase 50% by 2030 Corn and small grains Residue/grain ratio for soybean increase from 1.5:1 to 2.0:1 Machine to recover 75% stover No tillage adopted universally

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

16. 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 > 100%. Wilson et al. 2004. Trans. ASAE 47:119-128.

17. Billion Ton Report Agriculture Assumptions AssumptionAssessment Yield increase 50% by 2030Doubtful Residue:grain ratio for soybean increase from 1.5:1 to 2.0:1 Achievable, but of doubtful use Machine to recover 75% stoverVery achievable No tillage adopted universallyDoubtful

18. Erosion control Traditional uses of crop residues Feed and bedding Soil amendment Soil carbon Plant nutrients

19. and Stover harvest Soil C change Soil carbon Time Management change Cultivation Pre-cultivation steady-state No tillage Cover crops Green manure REAP

20. Residue needed to maintain SOC Crop rotationTillageMg ha -1 n Cornmbp7.5±1.06 Wheatmbp5.5±1.15 Allmbp6.3±1.013 AllChisel/nt4.5±0.45 Johnson et al. 2006. Agron. J. 98:622-636. REAP

21. Change allocation of biomass REAP

22. Change allocation of biomass REAP

23. Change allocation of biomass vs. increase total biomass production Increase photosynthetic efficiency 25%, from 4% 5% REAP Long et al. 2006. Plant Cell Envir. 29:315-330.

24. Multiple biomass Many technologies Conservation Reduced expectations Asking and answering the right question