The purpose of this project is to define the amount of slaked lime needed for a given clay soil. We hypothesise that the amount of slaked lime needed for minimal phophorus loss is dependent on the clay content of the soil. The study will be conducted in a field with a drainage system and measuring station for sampling runoff and leachates. We also conduct investigation in the laboratory, where we test five soil texture classes (10-15%, 20-25%; 30-35%, 40-50%, > 50 %). This test will help us to develop a simple decision support tool for calculating the amount of slaked lime required to amend clay soils depending on their clay content.The study will be evaluated by measuring soil aggregate stability and by determining phosphorus content in leachates and runoff.