Anthropogenic enrichment of soil nitrogen (N) and phosphorous (P) has dramatically altered ecosystem structures and functions. However, our understanding of the interactions between soil nutrient enrichment and arbuscular mycorrhizal (AM) fungi with plant community performance remains elusive. We examined the impacts of soil N and P enrichment and mycorrhizal suppression on plant community composition and productivity in desert steppe. Our results showed that short-term addition of P alone and combined N and P had stronger influence on plant community composition and productivity, but the addition of N alone had a minimal effect. Individual and combined addition of N and P mainly altered plant community productivity by increasing the biomass of annual forbs, but decreasing that of perennial forbs and C₃ grasses, regardless of AM fungi. AM fungal suppression did not alter plant community composition and productivity. Addition of P alone and combined N and P slightly increased plant species richness and diversity. Our findings highlight that the short-term N and P enrichments, rather than the presence of AM fungi, change plant community dynamics in desert steppe.

土壤氮（N）和磷（P）的人为富集显着改变了生态系统的结构和功能。然而，我们对土壤养分富集和丛枝菌根 (AM) 真菌与植物群落表现之间相互作用的理解仍然难以捉摸。我们研究了土壤 N 和 P 富集和菌根抑制对沙漠草原植物群落组成和生产力的影响。我们的结果表明，短期单独添加 P 和 N 和 P 组合对植物群落组成和生产力的影响更大，但单独添加 N 的影响很小。N和P的单独和组合添加主要通过增加一年生杂草生物量来改变植物群落生产力，但降低多年生杂草和C ₃生物量草，不管 AM 真菌。AM 真菌抑制没有改变植物群落组成和生产力。单独添加 P 和结合 N 和 P 略微增加植物物种的丰富度和多样性。我们的研究结果强调，短期 N 和 P 富集，而不是 AM 真菌的存在，改变了沙漠草原的植物群落动态。