Agriculture as a source of phosphorus causing eutrophication in Central and Eastern Europe

There are considerable differences between the EU-15 countries and Central and Eastern European (CEE) countries in the application rate of phosphorus (P) fertilizer and manure as well as in the climate and erosion patterns, but the eutrophication of surface waters is a common problem. The availability of information on the contribution of the CEE countries to European surveys on eutrophication is not adequate, because the amount of data available from these countries is small. There is thus a need to compile more comprehensive data sets for better assessment. Recent changes in agricultural practices, and their impact on the trophic status of surface waters in CEE countries, have been evaluated using a few selected pressure and state indicators (phosphorus balance, phosphorus status and erosion of agricultural land, P loss risk index, chlorophyll a, total and orthophosphate content of water) by compiling and analysing data from the literature. In the CEE countries, small annual P balances (-7 to +6 kg P ha⁻¹) and declining levels of soil available P (proportion of soils adequately supplied with P dropped to between 10 and 50% of total area) may lead to low yields and economic difficulties. Only 11% of the variation in total phosphorus (TP) in rivers studied could be attributed to the calculated P loss risk index, and thus to the impact of differences in the agricultural diffuse source P load. The generation of more consistent data sets should be pursued for the whole of Europe in order to derive more powerful indicators. A refined P index could be one of the best indicators of eutrophication. Recent changes in the trophic level of surface waters could be attributed to a large extent to the change in point source P loads, i.e. to the diminishing amount of P load from municipal and industrial wastewater. The short-term improvement of water quality in the CEE countries will require further improvements in wastewater treatment, but long-term improvement will only be achieved by reducing diffuse P losses from agriculture, possibly involving changes in the land use pattern and in farming practices.