1. Graduate Program in Applied Ecology (CENA/ESALQ), University of São Paulo, Piracicaba, SP, Brazil
2. Department of Soil Science, “Luiz de Queiroz” College of Agriculture, University of Sao Paulo, Piracicaba, SP, Brazil
3. Department of Sciences ‘Luiz de Queiroz’ Agricultural College, University of Sao Paulo, Piracicaba, SP, Brazil