1. Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
2. Research Institute for Humanity and Nature, 457–4 Kamigamo-motoyama, Kita-ku, Kyoto 603-8047, Japan
3. Center for Ecological Research, Kyoto University, Kamitanakami-hirano-cho, Otsu, Japan
4. Graduate School of Agriculture, Kyoto University, Kyoto, Japan
5. Laboratory of Soil Chemistry, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto, Japan