1. Department of Earth and Space Science and Engineering, York University, 4700 Keele St., Toronto, Ontario, Canada, M3J 1P3.
2. Agriculture and Agri-Food Canada, Central Experimental Farm, K. W. Neatby Room 2091, 960 Carling Ave., Ottawa, Ontario, Canada, K1A 0C6.
3. Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Avenue S., Lethbridge, Alberta, Canada, T1J 4B1.