Jian Liu1, Peter J. A. Kleinman2, Helena Aronsson3, Marianne Bechmann4, Douglas B. Beegle5, Ray B. Bryant6, Don Flaten7, Hongbin Liu8, Richard McDowell9, Timothy P. Robinson10, Andrew N. Sharpley11 and Tamie L. Veith2, (1)Department of Plant Science, University of Saskatchewan, Saskatoon, SK, CANADA, (2)Pasture Systems and Watershed Management Research Unit, USDA-ARS, University Park, PA, (3)Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden, (4)Div. for Environment and Natural Resources, Norwegian Institute of Bioeconomy Research, Ås, Norway, (5)Plant Science, Pennsylvania State University, University Park, PA, (6)Curtin Road, USDA-ARS, Spring Mills, PA, (7)Department of Soil Science, University of Manitoba, Winnipeg, MB, Canada, (8)Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China, (9)Faculty of Agriculture and Life Sciences, Lincoln University, Christchurch, NEW ZEALAND, (10)Livestock Systems and Environment Research Theme, International Livestock Research Institute, Nairobi, Kenya, (11)115 Plant Sciences Bldg., University of Arkansas, Fayetteville, AR