In the Netherlands, home-grown roughage, including silage maize, is essential for dairy farms. An important aspect of growing maize is the optimal use of nitrogen. With derogation restrictions in place, every kilogram of nitrogen (N) that farmers can apply counts. Nitrogen that no longer increases maize yields is better used on grassland. But where is the tipping point? Knowledge of the soil, previous crops and field management history helps farmers fine-tune nitrogen application. But it takes more than a few quick calculations on a notepad. NDICEA is a calculation tool that links expected yields to soil fertility, weather conditions and field management history to predict nitrogen dynamics and balance. How much nitrogen is there? When will it be released? Is it enough? Last season, our Crop Nutrition Clubs tested NDICEA and provided feedback to the tool's developers to improve the input options. Features such as manual input for grassland cuts and an adapted maize growth curve will improve the accuracy of the tool for nitrogen fertilisation in maize.