Trends in nutrient concentrations in Latvian rivers and the response to the dramatic change in agriculture

Thus, the extensive decrease in agricultural intensity that began in the early 1990s has led to only a slow and limited (especially regarding nitrogen) response in Latvian rivers. The difference noted between nitrogen and phosphorus also suggests that factors other than reduced fertiliser application influenced the inertia of the water quality response. Our findings, along with those obtained in similar studies, show that large cuts in nutrient inputs do not necessarily cause an immediate response, particularly in medium-sized and large catchment areas. (C) 2003 Elsevier B.V. All rights reserved.