1. Department of Agroecology, Danish Institute of Agricultural Sciences, Research Center Foulum, DK‐8830, Tjele, Denmark
2. Soil Ecology & Biotechnology Laboratory, GAIA Environmental Research and Education Center, Kifissia, Greece
3. Institute of Plant Nutrition and Soil Science, Kiel University, D‐24118 Kiel, Germany
4. Department of Agricultural Engineering, Danish Institute of Agricultural Sciences, Research Centre Bygholm, DK‐8700 Horsens, Denmark