1. Biosystems Engineering Department, Luiz de Queiroz College of Agriculture, University of Sao Paulo (USP), Piracicaba 13418-900, SP, Brazil
2. Applied Economics Department, Luiz de Queiroz College of Agriculture, University of Sao Paulo (USP), Piracicaba 13425-075, SP, Brazil
3. Experimental Field of Gorutuba, Minas Gerais Agricultural Research Agency (EPAMIG), Nova Porteirinha 39525-000, MG, Brazil