1. Department of Soil Science and Environment, Faculty of Agriculture; Khon Kaen University; Khon Kaen Thailand
2. Soil Organic Matter Management Research Group; Khon Kaen University; Khon Kaen Thailand
3. Department of Agricultural Technology, Faculty of Technology; Mahasarakham University; Maha Sarakham Thailand
4. Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg Institute); University of Hohenheim; Stuttgart Germany
5. Land Development Department; Office of Soil Research and Development on Land Management; Bangkok Thailand