To investigate the effects of staged nitrogen （N） application combined with the nitrification inhibitor 3，4-dimethylpyrazole phosphate （DMPP） on nitrogen uptake， utilization， and yield of forage oat （Avena sativa L.）， a field experiment was conducted with seven N fertilizer treatments： no N application （CK）， conventional N application （105 kg·hm^-2， N₁₀₅； 210 kg·hm^-2， N₂₁₀； 300 kg·hm^-2， N₃₀₀）， reduced-staged optimized N application （168 kg·hm^-2， O₁₆₈）， and reduced-staged optimized N application combined with DMPP （O₁₆₈+D， O₁₄₄+D） The results showed that compared with conventional N application， the O₁₆₈+D treatment achieved the highest yield of 7412.13 kg·hm^-2， which was significantly higher than that of under conventional N application （P<0.05）. Compared to the N₂₁₀ treatment， the oat plant nitrogen uptake， nitrogen agronomic efficiency， and nitrogen use efficiency increased by 4.90%， 48.51%， and 6.44% in O₁₆₈+D treatment， respectively. Therefore， under the condition of Horqin aeolian sandy soil， the optimized treatment-combining reduced-staged application of N with DMPP can increase the yield and improve the N use efficiency of forage oat. These findings provide a theoretical basis for enhancing the yield of forage oat and optimizing N fertilizer application in the Horqin Sandy Land.

Forage oats  /  Nitrification inhibitor  /  Nitrogen fertilizer application rate  /  Nitrogen use efficiency  /  Yield