Alfred S. Likuku1, Derek Branford2
1Botswana College of Agriculture, Private Bag 0027, Gaborone, Botswana
2School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building,
Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
Pol. J. Environ. Stud. 2011;20(2):405–410