Isaac R. Fandika
Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North, New Zealand

P.D. Kemp
Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North, New Zealand

J.P. Millner
Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North, New Zealand

N. Rostridge
Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North, New Zealand

D. Horne
Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North, New Zealand