1. Division of Soil and Water Management, Department of Earth and Environmental Sciences; KU Leuven; Kasteelpark Arenberg 20 bus 2459, 3001, Leuven Belgium
2. Soil Service of Belgium; Willem De Croylaan 48, 3001, Heverlee Belgium
3. Plant Sciences Unit - Crop Husbandry and Environment; Institute for Agricultural and Fisheries Research; Burgemeester Van Gansberghelaan 109, 9820, Merelbeke Belgium