氮沉降的增加对草地生态系统结构和功能造成了诸多负面影响,包括改变植物群落结构和降低植物养分利用效率.许多国家的减排政策有效地减少了氮排放、降低了氮沉降速率,但历史氮沉降对生态系统的影响可能具有遗留效应.草地植物群落的养分利用效率在氮沉降减少或者停止后作出何种响应,还有待于研究.作为草地重要的管理方式之一,刈割将如何调控历史氮沉降对植物养分利用效率的影响仍然属于知识空白.本研究探讨了氮素添加停止以后连续3年内功能群水平和群落水平上植物的氮、磷利用效率对历史氮素添加和刈割处理的响应.研究结果表明,历史氮素添加显著降低了植物功能群水平的氮利用效率,但未改变其磷利用效率;在群落水平上,历史氮素添加显著降低了植物的氮磷利用效率.刈割能够缓解历史氮素添加对植物群落氮磷利用效率的降低作用,该作用主要是抑制具有较低养分利用效率的根茎型高禾草的生长而促进具有较高养分利用效率的丛生型高禾草的生长.研究结果揭示了植物群落结构在驱动植物群落养分利用效率变化中的重要作用.本研究认为适当的草地管理方式有助于氮沉降过后草地植物养分利用效率的恢复.“,”Aims Plant nutrient use efficiency,an important factor driving primary production,is sensitive to nitrogen(N)deposition.Because of strengthened regulations of N emissions,atmospheric N deposition is decreasing in many countries.It remains unknown whether historical N enrichment would alter plant nutrient use efficiency and whether such impacts would be mitigated by ecosystem management strategy.Methods We assessed the effects of historical N addition and mowing on plant N and phosphorus use efficiency(NUE and PUE)at both functional group and community levels in a temperate steppe after the cessation of 6-year N addition.Important Findings Historical N addition had negative legacy effects on plant NUE but not on PUE at the functional group level.There were negative legacy effects of N addition on community-level NUE and PUE,but only in the unmown plots.Mowing mitigated the negative legacy effects of N enrichment on community-level NUE and PUE by reducing the dominance of tall rhizomatous grass but enhancing that of tall bunchgrass.Our results highlight the importance of community composition variations caused by mowing in driving the legacy effects of N enrichment on community-level nutrient use efficiency.Given the slow recovery of community composition following cessation of N deposition,our findings suggest that the lower nutrient efficiency of plant community would be long-lasting.