USING REMOTE-SENSING FOR MONITORING OF AUTUMN TILLAGE IN NORWAY

Management systems on agricultural land in Norway are causing concern because of increasing area wide soil erosion, consequent increase in s ediment loads and nutrient losses to waters, and their consequent poll ution. Monitoring of areas in autumn is important because this is the start of a season when much of the erosion occurs. This is often cause d by management systems in autumn, but also because climatic condition s in this season are important for erosion processes. We have investig ated several sources of remote sensing data, with a view to assembling the best overall monitoring system for this geoscience problem. The s ources were digitised CIR (colour infrared pseudocolour) aerial photog raphy, SPOT and ERS-1 SAR. CIR photography proved more accurate than S POT data, especially with regard to exposed soils as result of CIR's c ontinuous spectral sensitivity. We found that SPOT is clearly limited as a monitoring tool for soils and there is a need for better sensors in range 680 to 790 nm wavelengths. ERS-1 SAR provides information whe n the optical sources cannot, but is dependent on good digital elevati on models. We found that the most effective monitoring is done using a combination of microwave and optical sources.