Risiko des Eintrags von Phosphor in den Hallwilersee durch Bodenerosion

Abstract. An important factor in the release of phosphorus by soil erosion, with corresponding consequences on the quality of surface waters, is the formation of aggregates and their stability. Around the eutrophic Lake Hallwil six arable lands were examined in five repetitions regarding aggregate and particle size distribution, P-contents of the different fractions and aggregate stability. Central to this was the use of the setting column for fractionation of soil samples. In the case of Lake Hallwil the risk of phosphorus discharges by soil erosion seems low since the phosphorus is mainly bound in aggregates which are transported over short distances only. Thus other pathways (runoff from grassland, leaching via drains) may be more important.