1. a Environmental Earth Observation Group, CSIRO Land and Water , Canberra GPO Box 1666, ACT, 2601, Australia
2. b University of New Brunswick , PO Box 44555, Fredericton, NB, E3B 6C2, Canada
3. c Potato Research Centre, Agriculture and Agri-Food Canada , PO Box 20280, Fredericton, NB, E3B 4Z7, Canada