Agriculture as a source of phosphorus for eutrophication in southern Europe

Large areas of the southern European Countries possess a Mediterranean climate, which influences soil properties, land use, fertilizer application practices and pathways of phosphorus (P) loss from agricultural soils. On average, inputs of fertilizer P exceed P exports from the agricultural areas in these countries; however, large differences in P surplus/deficit and soil P test values exist among regions. Losses of P in drainage water are modest except in some irrigated areas and in those regions where intensive animal production is concentrated. Losses of P in runoff water, whether as dissolved reactive or particulate P, can be substantial as a result of the significance of erosive processes under the land uses typical of the Mediterranean region, where extreme rainfall events contribute disproportionately to such losses. Eutrophication due sensu lato to agricultural P sources affects a relatively high proportion of rivers, lakes and reservoirs. The typical Mediterranean climate and patterns of land use result in marked seasonality in the concentration of P in surface waters. Despite the growing number of studies conducted, the contribution of agricultural P to eutrophication in southern European countries remains largely unassessed and thus warrants pertinent research at the soil, field and catchment scales.