Maize is one of the most important crops, especially on dairy farms. Because dairy farms are so nutrient-rich, they are often associated with nitrate leaching. To avoid N leaching during the winter period, the implementation of catch crops is important. Together with root fertilization and organic fertilizers, nitrogen can be used very efficiently and mineral fertilizers can be replaced. The combination of catch crops and organic root fertilization stabilizes yields, reduces costs for mineral fertilizers and reduces necessary storage for slurry or manure. At the same time, N-losses in the environment are reduced.