Effects of nitrogen fertilizer addition on forage nutrition quality and community structure in temperate meadow steppe of Inner Mongolia

To study the effects of different fertilizer rate and fertilizer methods on forage nutrition quality and plant community structure in temperate meadow steppe of Inner Mongolia, we designed two nitrogen addition methods with scattering application and row application and five different fertilization amounts (0, 6, 12, 20 and 32 g·m⁻²). We measured community height, cover, density, and biomass, and calculated the diversity index. Meanwhile, we determined the neutral detergent fiber, acidic detergent fiber, and crude protein contents in mid-August from 2019 to 2021 and calculated the relative feeding value. The results showed that different fertilization additions had no significant effects on neutral detergent fiber, acid detergent fiber, crude protein, and relative feeding value (P > 0.05). Nitrogen fertilizer addition significantly decreased neutral and acidic detergent fiber but significantly increased crude protein content and relative feeding value (P < 0.05). With the accumulation of years, the evenness index, dominance index, and Shannon-Wiener index all showed a significant decreasing trend (P < 0.05). The proportion of edible forage increased. This study has shown that nitrogen fertilizer addition can improve forage quality in Inner Mongolia temperature meadow steppe.