Global and regional phosphorus budgets in agricultural systems and their implications for phosphorus-use efficiency - Lun, Fein (China Agricultural University. College of Resources and Environment Sciences) ; Liu, Jungo (South University of Science and Technology of China. School of Environmental Science and Engineering) ; Ciais, Philippe (Centre d'Etudes Orme des Merisiers) ; Nesme, Thomas (Université de Bordeaux. Bordeaux Sciences Agro) ; Sardans i Galobart, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals) ; Peñuelas, Josep (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)