Effects of native grass-legume mixed reseeding and fertilization on ecosystem restoration in temperate typical degraded steppe

Globally, grassland degradation threatens ecosystem stability and sustainable livestock production, with reseeding and fertilization being widely adopted restoration measures. However, their individual and interactive effects on plant communities, soil nutrients, forage quality, and functional group allocation remain poorly understood. To address this gap, a split-plot experiment was conducted in Hulunbuir, Inner Mongolia, with five reseeding combinations (R 1 –R 5 ) and two fertilization treatments (F 1 , F 2 ). Our results showed that reseeding significantly increased aboveground biomass (AGB), among which the native grass-legume mixed combination (R 3 ) performed best, enhancing community diversity and improving forage nutritional quality. Fertilization treatment (F 2 ) increased the soil organic carbon (SOC) content by 2.92% and available phosphorus (AP) content by 83.02% in the topsoil (0–15 cm), but had no significant effects on subsoil (15–30 cm) nutrients or plant community diversity. The native grass-legume mixed reseeding combined with fertilization (R 3 F 2 combination) yielded the highest biomass proportions of grasses (41.48 ± 2.26%) and legumes (29.40 ± 1.36%), and the lowest proportion of forbs (29.12 ± 3.61%). This study confirms that native grass-legume mixed reseeding, combined with fertilization, can synergistically improve plant community productivity, topsoil fertility, and forage nutritional quality in degraded typical steppes. Our findings provide critical insights for optimizing restoration strategies and promoting the sustainable management of degraded grassland ecosystems.