Nowadays,  the  main  objectives  of plant  crop growers  aim  at  two targets  (i) increasing food production  and  (ii)  simultaneously,  reducing  the  environmental impact  of increasing fertilizer nitrogen  consumption.  On  a  global  scale, fertilizer nitrogen  recovery  ranges  from 33  to 50%. The  required  efforts stimulating production  but  protecting  the  environment focus  on increasing unit productivity of fertilizer N. Magnesium, owing to its  biological  functions  in plants, should play a much  more important   role  In  modern  agriculture  controlling N economy of crop plants  and,  consequently,   nitrogen  dispersion  in  the environment.  In Poland, arable  soils  are generally  poor in  total  and  available magnesium.  This  state can  be considered  as  indicating the  necessity  of applying  magnesium  and then maintaining a wellfeed plant  nutritional status  of growing  crops.  Crops  well supplied  with  magnesium since the  beginning  of their growth, as  seen  from studies  on  the  response  of sugar  beets  and maize,  are  in  a  position  to increase  nitrogen  unit  productivity. Cereals  respond  to Mg supply  when  a dressing treatment  takes  place  just  before  the onset  of flowering. Another factor  significantly affecting fertilizer nitrogen recovery in  Poland  is soil  pH. Acid soils fertilized   with  Mg  contain increased soil exchangeable  Mg  levels, which  in turn  depress the pressure of toxic aluminum on  growing crops.  Improvement   of the  plant  Mg  nutritional status enables plants  to incorporate  some of potentially residual N  into  biomass, increasing biomass  yield.   It can therefore  be concluded that  magnesium,  owing  to  its ameliorating function in arable soils, meets the main requirement of sustainable nitrogen management, both in agriculture and  in the environment.