[1] Inst Agron Parana, Area Fitotecnia, BR-85501970 Pato Branco, Parana, Brazil
[2] Univ Fed Santa Catarina, Ctr Ciencias Agr, Dept Engn Rural, Florianopolis, SC, Brazil
[3] Univ Calif Berkeley, Dept Ciencias Ambientais Polit & Gestao, Berkeley, CA 94720 USA