1. Soil and Water Management & Crop Nutrition Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications International Atomic Energy Agency Vienna Austria
2. Division of Soil and Water Management, Department of Earth and Environmental Sciences KU Leuven Leuven Belgium
3. Institute of Soil Research, Department of Forest and Soil Sciences University of Natural Resources and Life Sciences Vienna Vienna Austria
4. COLEACP Brussels Belgium