1. Department of Agronomy and Horticulture University of Nebraska–Lincoln Lincoln Nebraska USA
2. Department of Plant, Soil and Microbial Sciences Michigan State University East Lansing Michigan USA
3. Department of Plant and Soil Sciences University of Kentucky Lexington Kentucky USA
4. Soil and Crop Sciences Section, School of Integrative Plant Science Cornell University Ithaca New York USA
5. Department of Plant and Environmental Science Clemson University Clemson South Carolina USA
6. Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire USA
7. Michigan State University Extension Centreville Michigan USA
8. Department of Plant Science and Landscape Architecture University of Maryland College Park Maryland USA