1. Automated field monitoring of soil nitrate levels;Adsett,1991
2. Soil nutrient mapping implications using GPS;Delcourt;Comput. Electron. Agric.,1994
3. The use of on farm meteorological data for resource utilization in sustainable crop production;Gronbech Hansen,1994
4. Response of winter barley to nitrogen;Grylls,1982
5. Precision farming: Economic views. Precision farming: Issues and opportunities;Hall,1994