1. Laboratory Director, National Laboratory for Agriculture and the Environment Ames IA 50011
2. Agronomy Dep. Univ. of Florida Gainesville FL 32611
3. USDA‐ARS, U.S. Arid-Land Agricultural Research Center Maricopa AZ 85138
4. USDA Crop Systems and Global Change Lab. Beltsville MD 20705
5. Joint Global Change Research Institute, Pacific Northwest National Lab. Univ. of Maryland College Park MD 20740
6. USDA/ARS, Photosynthesis Research Unit, Univ. of Illinois Urbana IL 61801
7. Dep. of Horticulture Cornell Univ. Ithaca NY 14853