1. Research Fellow, National Centre for Engineering in Agriculture, Univ. of Southern Queensland, Toowoomba, QLD 4350, Australia (corresponding author).
2. Emeritus Professor, Univ. of Southern Queensland, Toowoomba, QLD 4350, Australia.
3. Senior Research Fellow, National Centre for Engineering in Agriculture, Univ. of Southern Queensland, Toowoomba, QLD 4350, Australia.
4. General Manager, Rubicon Water, Wheeler St., Shepparton, VIC 3630, Australia.
5. Manager, Rubicon Water, Wheeler St., Shepparton, VIC 3630, Australia.