The Netherlands simply has too many farm animals and overfertilization has been a problem for decades. This is especially visible on this map from 2011 [1]. The overfertilization will lead to biodiversity loss, as plants that prefer nutrient poor soils will be outcompeted by plants that can harness the excess nitrogen and/or that prefer acidic soils [2]. Due to EU regulation and court orders only recently did this become a real mess, where building projects couldn't even continue because of the limits on nitrogen emissions.
[1] https://commons.wikimedia.org/wiki/File:Europe_Global_Fertil...