THE ROLE OF SOIL TEST INFORMATION IN REDUCING GROUNDWATER POLLUTION

Testing soils for nutrients is expected to improve groundwater quality . However, it is unknown whether soil testing will improve groundwater quality sufficiently to decrease the demand for direct regulation of agricultural practices. Focusing on an irrigated agricultural region i n eastern Oregon, the economic and environmental aspects of soil testi ng are assessed using a spatially distributed, dynamic simulation mode l which links economic behavior with the physical processes that deter mine groundwater quality. Results indicate that soil testing of all fi elds increases farm profits and reduces groundwater nitrate concentrat ion. However, the benefits are small in terms of potential improvement s in groundwater quality.