1. Soil Science Department University of São Paulo, “Luiz de Queiroz” College of Agriculture Pádua Dias Av., Box 9, 13418‐900 Piracicaba São Paulo Brazil
2. Soil Sciences Department São Paulo State University – Campus of Jaboticabal Via Acesso Prof. Paulo Donato Castellane s/n Jaboticabal São Paulo 14884‐900 Brazil
3. Agronomy Department University of Florida, Institute of Food and Agricultural Sciences – Everglades Research and Education Center 3200, East Palm Beach Road Belle Glade FL 33430 USA
4. 10 Hornbeam Close York YO306RD UK
5. Professor Emeritus Washington State University 2640 Cobbs Way Palm Harbor FL 34684 USA