Grassland is the primary land use in China, which has experienced extensive degradation in recent decades due to overexploitation. Here, we conducted field experiments to quantify the degraded grassland’s recovery rate in Northeast Inner Mongolia in response to restoration measures, including fallow + enclosure (FE) and mowing + enclosure (ME) in comparison to livestock grazing (LG), since 2005. Plant community properties were surveyed and aboveground biomass (AGB) sampled in summer 2013. Our results showed that the regional dominant species Leymus chinensis retained its dominance under FE, whereas a range of forb species gained dominance under LG. Vegetative cover was maximal under FE and minimal under LG. The least amount of vegetation development and AGB were observed under LG. However, plant diversity showed an opposite pattern, with maximal diversity under LG and minimal under FE. Statistical analysis revealed that AGB was negatively associated with plant diversity for all treatments except ME. For ME, a positive AGB-diversity relationship was characterized, suggesting that mowing intensity was a controlling factor for the AGB-diversity relationship. Overall, these results demonstrated that enclosure plus mowing represented an effective conservation measure that provided fair support to forage production and a progressive pathway to a more resilient grassland system.

Rhizobium inoculation can improve alfalfa performance, but responses depend on both plant genotype and growing environment. We first screened 14 rhizobial strains plus one commercial inoculant with Medicago varia ‘Caoyuan No. 3’ (CY3) in a greenhouse pot experiment, together with an uninoculated control (16 treatments; three pots per treatment). Based on plant height, root length, leaf number, nodule number, and above- and belowground biomass after two months, SJN, HH, and HK were selected as higher-performing strains, whereas XBC, SWL, and XH were retained as lower-performing comparators. These six strains were then evaluated with CY3, Medicago sativa ‘Aohan’ (AH), and M. sativa ‘Adrenalin’ (ADN) in a replicated field experiment. Individual growth and nutritional responses varied among varieties and growth stages. At flowering, XH increased CY3 above-ground biomass by 113% relative to CK, whereas the reported TOPSIS composite ranking placed CY3+XBC first overall. The corresponding composite rankings placed AH+SJN and ADN+SWL first; notably, CK ranked second for ADN. Thus, ‘optimal’ refers to the highest reported composite score across the measured growth, nodulation and nutritional indicators, not superiority for every individual trait. Because symbiotic nitrogen fixation was not measured directly and a pre-sowing physicochemical baseline for the field soil was unavailable, the findings should be interpreted as context-dependent agronomic responses rather than direct quantification of nitrogen fixation or remediation of saline soil.