1. a Department of Natural Resources , Natural Sciences Precinct and CRC for Sustainable Sugar Production , Indooroopilly , Qld , 4068 , Australia E-mail:
2. b Department of Soil and Crop Sciences , Colorado State University , Fort Collins , CO , 80523–1173
3. c Centre for Soil and Agroclimate Research , Jln. Ir. Juanda 98, Bogor , 16123 , Indonesia