The objective of this study was to reveal the effects of different forms of nitrogen fertilizers on perennial alpine cultivated grassland plant communities and soil properties. A 4-year-old perennial mixed-seeded grassland established in 2019 at Qinghai University’s comprehensive experimental demonstration base of plateau specialty agriculture and animal husbandry was used as the research object. Four treatments of control （CK）， amide nitrogen fertilizer （U）， ammonium nitrogen fertilizer （A） and nitrate nitrogen fertilizer （N） were set up to determine and analyze treatment effects on the plant community structure， soil physicochemical properties and microbial biomass. The results showed that application of different forms of nitrogen fertilizers significantly affected plant productivity， soil physicochemical properties and microbial biomass of artificial grassland， while the effect on plant diversity was not significant. Different forms of nitrogen fertilizers showed U>N>A in promoting plant productivity， with an increase of 62.60%， 53.71% and 25.85% over control. respectively. Application of amide nitrogen fertilizer significantly increased soil water content and soil conductivity and significantly decreased soil bulk density and pH value. Application of ammonium nitrogen fertilizer significantly increased total phosphorus and decreased soil microbial biological carbon to nitrogen ratio. Application of nitrate nitrogen fertilizer significantly increased soil quick phosphorus， total nitrogen， microbial biochar and microbial biochar-phosphorus ratio. Redundancy analysis showed that soil pH value and bulk weight were key soil factors influencing perennial alpine cultivated grassland plant communities. In summary， it is recommended that amide nitrogen fertilizers should be given priority in the development of nitrogen application programs for perennial alpine cultivated grassland productivity maintenance and soil improvement.

Alpine cultivated grassland  /  Nitrogen form  /  Plant community  /  Soil physicochemical properties  /  Microbial biomass