Collaboratrices et collaborateurs

The official fertilizer recommendation dates back to 1938 in Switzerland. Since then, methods, resources, justification and environmental impact of nutrient use in agriculture changed largely. Today we foster two site and use specific methods: a soil sampling and a model-based estimation of crop fertilizer demand for N and P. However, those methods are not an integral part of the Swiss legislation (law enforcement) allowing for significant losses to the environment causing significant environmental and resource problems such as surface water eutrophication and nitrate pollution of drinking water reserves. Consequently, a better integration of good and best fertilizer practices in legislation is one of several challenges for a sustainable nutrient management in Switzerland. Others are the 1. digital transformation closing the gap of information use between field and farm, extension, legislation and environmental and national monitoring, 2. Improvement of fertilizer recommendation, by better calibration to pedo-climatic conditions, estimation of nutrient release from fertilizers and soils using multi-factorial statistics and models and 3. a better integration of spatial and temporal variability by means of precision fertilization methods and technology. The presentation will be closed by a regional example of an intensive agricultural region having exceeded nitrate levels in their ground water reserves since decades. The example shows, how a multi-stakeholder consortium addresses the above-mentioned challenges in a co-creation process. In particular, the combination of the critical load concept and good fertilization practices, a robust documentation of nutrient application practices and nutrient balancing of all inputs is seen as the regional solution towards a drinking water resource fulfilling national quality standards combined with a productive agriculture in a region with fertile soils.