Effect of Soil Management on Soil Erosion and Phosphorus Losses in Northern Europe.

In cereal cropping systems, soil management is a major factor contributing to increased risk of soil erosion, transport of soil particles and losses of particulate phosphorus by water. We present results based on several studies undertaken in four North European countries on the effect of soil management on soil particle and phosphorus losses. The examined soil tillage methods include direct drilling (no-till), shallow cultivation and ploughing. Landscape features, such as e.g. slope length and angle, drain spacing, prior soil leveling, soil properties, soil tillage methods and their timing and a number of measured or derived climate-related variables were accounted for as potential explanatory variables. Besides using descriptive statistical measures, we used classification and regression tree analysis (CART) to explore what geological, landscape, climatic and management factors - or their combinations - are most influential in determining the success of tillage experiments in terms of reducing soil erosion and associated particulate phosphorus losses. Preliminary results show that, in general, deeper and more intense soil tillage results in greater soil erosion at the plot scale. The effect of soil tillage on losses of total phosphorus generally follows the pattern of soil losses by erosion, but the relationship between soil tillage and losses of phosphorus are much more complex.