1. New Zealand Institute for Plant & Food Research Ltd; Private Bag 4704 Christchurch 8140 New Zealand
2. Department of Soil Science; University of Saskatchewan; Saskatoon SK S7N 5A8 Canada
3. College of Hydraulic and Architectural Engineering; Northwest A&F University; Yangling 712100 China
4. School of Environmental Sciences; University of Guelph; 50 Stone Road East Guelph ON N1G 2W1 Canada
5. Department of Soil and Physical Sciences, Faculty of Agriculture and Life Sciences; Lincoln University; Lincoln 7647 New Zealand