1. University of Pannonia, Georgikon Faculty, Department of Crop Production and Soil Science; Deák F. u. 16 Keszthely 8360 Hungary
2. European Commission, Joint Research Centre (JRC), Institute for Environment and Sustainability (IES), Land Resource Management Unit, Via Enrico Fermi 2749; 21027 Ispra VA Italy
3. Bioforsk, Soil and Environment; Frederik A. Dahls vei 20 Ås 1430 Norway
4. Hungarian Academy of Sciences, Centre for Agricultural Research, Institute for Soil Sciences and Agricultural Chemistry; Herman Ottó út 15 Budapest 1022 Hungary
5. Aristotle University of Thessaloniki, School of Agriculture, Lab of Applied Soil Science, University Campus, UB 259; 54124 Thessaloniki Greece