The model predicted a linear increase in grain yield if nutrients are taken up in balanced amounts of 14.7 kg N, 2.6 kg P and 14.5 kg K per 1000 kg of grain until yield targets reached ca. 70±80% of the climate-adjusted potential yield (Ymax). The corresponding IEs were 68 kg grain kgˉ1 N, 385 kg grain kgˉ1 P and 69 kg grain kgˉ1 K for a balanced nutrition.