1. Dep. of Soil & Physical Sciences Faculty of Agriculture & Life Sciences PO Box 84 Lincoln 7647 New Zealand
2. Soils and Crops Research and Development Agriculture & Agri‐Food Canada 2560 Hochelaga Blvd. Quebec QC G1V 2J3 Canada
3. Soil Water & Environment Group, Plant & Food Research Canterbury Agriculture & Science Centre Gerald St. Lincoln 7608 New Zealand
4. Environmental Soil Science, Dep. of Agricultural Sciences FI‐00014 Univ. of Helsinki PO Box 56 Helsinki Finland
5. Institute for Atmospheric and Earth System Research/Forest Sciences FI‐00014 Univ. of Helsinki PO Box 27 Helsinki Finland
6. Viikki Plant Science Centre (ViPS) FI‐00014 Univ. of Helsinki PO Box 56 Helsinki Finland
7. Division of Ecosystem and Biomass Science, Forest & Landscape Univ. of Copenhagen Rolighedsvej 23 DK‐1958 Frederiksberg C Denmark
8. ADAS Boxworth Battlegate Road, Boxworth Cambridge CB23 4NN UK