To investigate the responses of forage growth and grassland soil nutrients to nitrogen fertilizer application， and to promote forage yield enhancement and soil nutrient balance， this study conducted a meta-analysis of 62 selected publications comprising 629 valid data sets. The analysis examined the effects of nitrogen fertilizer application on forage growth and soil nutrients under varying meteorological conditions （climatic zones， mean annual rainfall and mean annual temperature）， soil conditions （alkali-hydrolyzable nitrogen （AN）， total nitrogen （TN）， and organic matter （OM））， as well as the amount of nitrogen fertilizer applied （low， medium， and high）. The results indicated that nitrogen fertilizer application significantly enhanced forage growth and improved soil nutrient status. Specifically， forage height and dry matter yield increased by 25.7% and 58.4%， respectively， while soil TN， AN， and OM contents increased by 21.8%， 19.3%， and 9.0%， respectively. Nitrogen fertilizer application in wet， low-temperature regions most effectively promoted forage growth， whereas nitrogen fertilizer application in wet， high-temperature regions was more conducive to enhancing soil nutrient availability. Nitrogen fertilizer application to nutrient-poor grasslands resulted in a more pronounced increase in forage dry matter yield， and even low rates of N addition produced substantial benefits. Our results demonstrate that nitrogen fertilizer addition exerts positive effects on both forage productivity and soil fertility， providing a scientific basis for grassland fertilization decision-making.

Nitrogen fertilizer dosage  /  Plant height  /  Biomass  /  Soil nutrient content  /  Meta-analysis