1. Teagasc Crops, Environment & Land Use Programme Oak Park Research Centre CarlowIreland
2. Biology Dep. Maynooth Univ. Co. Kildare Ireland
3. Dep. of Agriculture, Food and the Marine Backweston Farm Leixlip Co. Kildare Ireland
4. Teagasc Research Operations Group Statistics and Applied Physics Dep. Ashtown Dublin 15Ireland
5. School of Agriculture & Food Science Univ. College Dublin Belfield Dublin 4 Ireland