1. U.S. Department of Agriculture‐Agricultural Research Service (USDA‐ARS), National Laboratory for Agriculture and the Environment (NLAE) University Boulevard Ames IA 50011–3611 USA
2. Dep. of Agricultural Engineering Federal Rural Univ. of Pernambuco Rua Dom Manoel de Medeiros, s/n, Dois Irmãos Recife PE 52171‐900 Brazil
3. Dep. of Agronomy State Univ. of Maringá Av. Colombo, 5790 Maringá Paraná 87020‐900 Brazil
4. USDA‐ARS NLAE (retired) DL Karlen Consulting LLC, 487 Ashland Ave. St. Paul MN 55102 USA