Sustainable Restoration of Typical Degraded Grasslands: An Evaluation of Ecological Benefits from Bio-Organic Fertilizer Applications

To investigate the effects of restoration measures on degraded grasslands in the typical steppe of Inner Mongolia, two restoration treatments—enclosure (EN) and enclosure with additional bio-organic fertilizer application (EF)—were established with moderately grazed degraded grassland as the control (MG). The impacts of these measures on vegetation community characteristics and soil physicochemical properties were systematically analyzed, and the post-restoration ecological benefits were quantitatively evaluated using an assessment system. The results showed that (1) over the two experimental years, both EN and EF treatments improved vegetation community characteristics and soil physicochemical properties, with the overall restoration effect ranking as EF > EN > MG; (2) compared with the first experimental year, the restoration of plant and soil characteristics was more significant in the second year; (3) ecological benefit analysis showed that the Soil Quality Index (SQI) decreases with soil depth. Compared to MG, the EF treatment increased topsoil SQI by 38.89–65.71% in the first and second years of restoration, respectively. Comparative evaluation indicated that EF led to more significant increases in vegetation community characteristics than MG. Thus, the EF treatment can significantly enhance the ecological benefits of typical degraded grasslands.