oleh Darmawan, .; Department of Soil Science, Faculty of Agriculture, Andalas University, Padang-25163, Indonesia , Yasin, Syafrimen; Department of Soil Science, Faculty of Agriculture, Andalas University, Padang-25163, Indonesia , Masunaga, Tsugiyuki; Faculty of Life and Environmental Science, Shimane University, Matsue 690-8504, Japan

oleh Darmawan, .; Faculty of Agriculture, Andalas University, Padang-25163, Indonesia. , Kyuma, Kazutake; Emeritus Professor of Kyoto University, 606-8501, Japan , Masunaga, Tsugiyuki; Faculty of Life and Environmental Science, Shimane University, Matsue 690-8504, Japan , Asmar, .; Faculty of Agriculture, Andalas University, Padang-25163, Indonesia. , Darfis, Irwan; Faculty of Agriculture, Andalas University, Padang-25163, Indonesia. , Wakatsuki, Toshiyuki; Faculty of Agriculture, Kinki University, Nara 332-7204, Japan

oleh Aflizar, .; State Polytechnic Payakumbuh for Agriculture, Campus Politani PO Box 107, Indonesia , Idowu, Alarima Cornelius; Faculty of Life and Environmental Science, Shimane University, Matsue 690-8504, Japan , Afrizal, Roni; State Polytechnic Payakumbuh for Agriculture, Campus Politani PO Box 107, Indonesia , Jamaluddin, .; State Polytechnic Payakumbuh for Agriculture, Campus Politani PO Box 107, Indonesia , Husnain, .; Indonesia Soil Research Institute, Bogor, Indonesia , Masunaga, Tsugiyuki; Faculty of Life and Environmental Science, Shimane University, Matsue 690-8504, Japan , Syafri, Edi; State Polytechnic Payakumbuh for Agriculture, Campus Politani PO Box 107, Indonesia , Muzakir, .; State Polytechnic Payakumbuh for Agriculture, Campus Politani PO Box 107, Indonesia