Abstract

The objectives of this study are, first, to describe the present use of fertilisers between the Regions III and wr of Chile, identifying the associated environmental impacts and their relationship with the predominant agricultural practices and climatic characteristics. Secondly, to simulate the transport of nitrates and pesticides in a dairy and breeding farm of the Central Valley of Chile, employing EPIC (USDA/ARS) in order to determine the importance of these contamination processes. In the North area of Chile, agricultural production generates soil and groundwater salinization problems due to low average rainfall and the use of highly efficient irrigation practices. In the Central zone, nitrate contamination due to agricultural diffuse pollution is evident; this is especially valid for groundwater contamination with nitrates. The South Central area suffers from eutrophication due to an increase in the nutrient levels in surface water. The simulation indicates that the dairy farm in the Central Valley of Chile has a soil loss of 5.02 tons/ha/year or of 14.67 tons/ha/year, based on MUSS or USLE estimates, respectively. It is important to point out that loss of NO3 and pesticides estimated by MUSS and USLE do not exceed maximum allowable standards. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.