Abstract: Field plot experiment was carried out during May 2012 to June 2014 to investigate the impacts of nitrogen fertilizations on the emissions of nitrous oxide (N₂O) and methane (CH₄) from alfalfa field as well as the dry matter yield and soil nitrate contents. Five treatments including CK, urea (100 kg N·hm^-2, CF), urea (100 kg N·hm^-2) + dairy cattle manure (60 kg N·hm^-2) (DM₁), urea (100 kg N·hm^-2)+ digestate (60 kg N·hm^-2) (DT) and reduced urea (40 kg N·hm^-2)+ dairy cattle manure (60 kg N·hm^-2) (DM₂) were conducted. Results indicated that in comparison with CK, CF, DM₁, DT and DM₂ treatments significantly increased the dry matter yields of alfalfa by 44.2%, 38.9%, 56.3% and 30.6%, and increased the N₂O emissions by 52.2%,89.1%, 133.7% and 59.4%, respectively, whereas the oxidation of atmospheric CH₄ was reduced to different extents by these N management practices. The losses of N₂O-N originated from urea and dairy cattle manure N accounted for 0.25%-0.28% of their inputs, whereas a greater va-lue of 0.64% was observed for digestate N. Applying urea or organic N to alfalfa field could significantly increase the dry matter yield without significant NO₃^--N leaching, however, it would lead to higher net CO_2-equivalent emissions of producing 1 t dry matter of alfalfa.