This work analyzes the efficiency of various fertilization strategies to reduce the emission of nitrogen compounds from the cultivation systems to the environment of the Murcia region. The work includes detailed “grid” scales and their integration at the provincial level. The historical evolution of N balances in the long term is analyzed (1860-2018) as well as the N flows between the main compartments of the system. Eight fertilization strategies were established, including the incorporation of manures, the use of urease inhibitors or the elimination of urea, studying the effect at the “grid” or aggregate scale on crop yield and emissions of nitrous oxide, ammonia or nitrate. It is concluded that there is a significant margin for improvement with hardly any penalty in performance.