Abstract: [Objective] To explore the effectiveness of different combinations of improvement measures for salinized-alkalized land in the Inner Mongolia region and provide a reference for the rehabilitation and utilization of salinized-alkalized grassland. [Methods] The study was conducted in a severely salinized-alkalized grassland in Sulide Sumu, Uxin Banner, Ordos City. Six treatment groups and one control group （CK） were established. The treatment groups included: No-till reseeding with Rumex proteingrass （SM）, No-till reseeding with mixed forage grasses （HM）, Deep tillage with straw application and planting with Rumex proteingrass （SN）, Deep tillage with humic acid application and planting with Rumex proteingrass （SF）, Deep tillage with straw application and planting with mixed forage grasses （HN）, and Deep tillage with humic acid application and planting with mixed forage grasses （HF）. Vegetation community height, coverage, above-ground biomass, and species importance value from 2021 to 2023, as well as soil pH and total salt content in the 0-20 cm and 20-40 cm soil layers were measured in 2021 and 2023. [Results] ①Community characteristics: Treatments involving deep tillage combined with humic acid or straw （SF, SN, HF, HN） significantly （P<0.05） increased community height and above-ground biomass compared to the control group. In 2023, the HN treatment showed the highest community height （113.1 cm） and above-ground biomass （309.8 g/m²）; community coverage varied across different years, with the HN treatment reaching 75% coverage in 2023, which was significantly （P<0.05） higher than the control. Species importance value results showed that Rumex proteingrass had poor adaptability and disappeared from the community after three years, while the mixed grass Puccinellia distans gradually became the dominant species in the HF and HN treatments （with the spelies value reaching up to 0.95）. ②Soil characteristics: Compared to 2021, the soil pH in the 0-20 cm and 20-40 cm soil layers of the SF, SN, HF, and HN treatments was significantly （P<0.05） reduced in 2023; the total salt content in the 0-20 cm and 20-40 cm soil layers of the SF and HF treatments was also significantly （P<0.05） decreased in 2023. [Conclusion] For the improvement of severely salinized-alkalized grassland, the combination of deep tillage with humic acid/straw application and planting mixed forage grasses （especially HN and HF treatments） is optimal. This combination not only significantly improves soil physical and chemical properties but also enhances vegetation community height, coverage, and productivity. Furthermore, the mixed species demonstrate strong adaptability and high community stability, supporting the sustainable utilization of salinized-alkalized grassland.

Key words: severely salinized-alkalized grassland, no-till reseeding, mixed planting, deep tillage combined with humic acid/straw application, vegetation community