1. Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9 Kita-Ku, Sapporo, Hokkaido 060-8589, Japan
2. Geology Department, University of Zambia, 10101 Lusaka, Zambia
3. Integrated Water Resources Management Center, Geology Department, University of Zambia, 10101 Lusaka, Zambia
4. Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9 Kita-Ku, Sapporo, Hokkaido 060-8589, Japan