1. Institute of Agricultural Chemistry and Soil Science, University of Debrecen, Debrecen, Hungary
2. Graduate School of Horticulture, Chiba University, Matsudo, Japan
3. College of Forestry, Henan Agricultural University, Zhengzhou, Henan, China
4. Kami-Ina Agricultural Extension Centre, Ina, Japan
5. Regional Environment Conservation Division, National Institute for Environmental Studies, Ibaraki, Japan