[Nitrogen cycle in grassland ecosystems]

agua del suelo air temperature analyse chimique application rates azote chemical analysis denitrification dose d'application eau du sol ecosistema ecosystems engrais npk fertilizantes npk feuille fixation de l'azote gramineas graminee grasses hojas leaves nitrogen nitrogen content nitrogen fixation npk fertilizers precipitation racine roots soil water stems tallo temperatura del aire teneur en azote tige