1. CSIRO Land and Water and the Cooperative Research Centre for Soil and Land Management; Private Mail Bag No. 2 Glen Osmond South Australia 5064
2. Soil, Plant and Ecological Sciences Division; P.O. Box 84, Lincoln Univ. Canterbury New Zealand
3. Dep. of Land and Water; Univ. of Adelaide; Waite Campus Urrbrae South Australia 5064
4. Dep. of Crop and Plant Sciences; Univ. of Georgia; Athens GA 30602 USA
5. Dionex Corporation; 1228 Titan Way Sunnyvale CA 94088-3606 USA