- Soil organic matter dynamics
- Carbon and nitrogen cycling in cropland and grassland ecosystems
- Sssessment of agricultural climate change mitigation strategies
- Evaluation of environmental impacts of agricultural bioenergy production
- soil organic matter dynamics
- Agroecosystem ecology
Extension and Outreach
- Acting as coordinating lead author for the Intergovernmental Panel on Climate Change (IPCC) dealing with agriculture and national greenhouse gas inventory methods.
- Co-chaired a Task Force on ‘Climate Change and Greenhouse Gas Mitigation: Challenges and Opportunities for Agriculture’ by the Council on Agricultural Science and Technology (CAST), and was lead author on a PEW Center report on ‘Agriculture’s Role in Greenhouse Gas Mitigation’.
- Serves on the US Carbon Cycle Science Steering Group, which provides expert input to Federal Agencies involved in climate and carbon cycle research, and a National Academy of Sciences panel evaluating GHG measurement methods.
- Serves on the Chicago Climate Change science advisory board, the 25X25 advisory board and the Soil Science Society of America Greenhouse Gas Working Group.