1. Dep. of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Botucatu São Paulo Brazil
2. Compass Minerals América do Sul Indústria e Comércio SA São Paulo São Paulo Brazil
3. Center for Tropical Roots and Starches São Paulo State University (UNESP) Botucatu São Paulo Brazil
4. Bayer Crop Science Uberlândia Minas Gerais Brazil
5. Dep. of Soil Water and Climate University of Minnesota St. Paul MN USA