1. DayCent Biofuel Modelling Efforts Bill Parton Steve Del Grosso Steve Ogle

2. Outline DayCent model description Model Testing –N 2 O –Soil C –Plant production Biofuel validation sites Biofuel model results Conclusion

3. CH 4 Uptake 0-1 cm 1-4 cm 4-15 cm 15-30 cm etc. N GAS 0-1 cm 1-4 cm 4-15 cm 15-30 cm etc. NO 3 - 0-15 cm NH 4 + 0-1 cm 1-4 cm 4-15 cm 15-30 cm etc. H 2 O soil T soil CO 2 ACTIVE 0.5-1 yr SOM SLOW 10-50 yr PASSIVE 1000-5000 yr CO 2 PLANT COMPONENTS LEAVES FINE ROOTS BRANCHES LARGE WOOD LARGE ROOTS DEAD PLANT MATERIAL STRUCTURAL METABOLIC NPP C:N Death N Uptake N inputs C:N Decomp RhRh RhRh N Min S, R h S S S S Decomp PPT, V, L Den Nit Stom ET V S = Soil Type V= Veg Type L = Land Use DAYCENT MODEL Parton, et al. 1998 Kelly et al. 2000 Del Grosso et al. 2001

6. Model Testing Agricultural Experiment Sites –N 2 O –Soil C –Crop yields Agricultural Census

9. Corn Grain Yields (21 Counties)

12. Biofuel Model Testing Sites Penn State Biofuel Plots –Corn, soybean, alfalfa, poplar Kellogg Biological Station Biofuel Plots –Poplar Nebraska Biofuel Plots –Switchgrass Data Sets –N 2 O –Soil C and N –Crop yields

13. Observed and DAYCENT N 2 O for Biofuel Cropping Systems in Pennsylvania

16. Cropping Systems Switchgrass Reed Canarygrass Corn-Soybean – (CT) Corn-Soybean – (NT) Corn-Soybean – ALFALFA (CT) Corn-Soybean – ALFALFA (NT) Hybrid Poplar

17. Greenhouse gas sources and sinks from bioenergy cropping systems in the near-term Adler, P.R., S.J. Del Grosso, and W.J. Parton. 2007. Life cycle assessment of net greenhouse gas flux for bioenergy cropping systems. Ecol. Appl. 17(3):675–691.

20. Grassland/Degraded Land

21. Conclusions Extensive data sets exist to test biofuel cropping models –Crop yields –Soil C and N –Trace gas fluxes DayCent model has been tested for biofuel crops –Pennsylvania –Michigan –Nebraska Current land use greatly impacts net greenhouse gas budgets of biofuel crops –CRP and grassland conversions