Saline–alkali soil salinization is a global ecological crisis affecting 932 million hectares of land worldwide, posing a severe threat to food security and ecological sustainability. Traditional improvement methods, such as chemical amendments and hydraulic engineering, are limited by high costs and environmental risks, whereas microbial amendments have emerged as eco-friendly and sustainable alternatives due to their ability to regulate soil microenvironments and enhance plant stress resistance. However, a comprehensive synthesis of their core mechanisms, global application progress, and regional adaptation characteristics is still lacking, hindering the standardization and promotion of related technologies. This review, conducted in accordance with PRISMA guidelines, systematically synthesizes 112 core studies (1990–2025) retrieved from Web of Science, Scopus, and CNKI databases, focusing on three core research objects: salt-tolerant microbial communities in saline–alkali soils (dominant taxa, functional genes, metabolic characteristics), development and optimization of microbial amendments (strain screening, composite formulation, carrier selection), and mechanisms and application effects of microbial remediation (soil–plant–microbe interactions, physicochemical improvement, crop growth promotion). Key findings include the following. (1) Dominant microbial taxa (e.g., Proteobacteria, Actinobacteria) exhibit region-specific adaptation strategies, with salt tolerance thresholds and functional characteristics varying by soil type (coastal vs. inland saline–alkali soils). (2) Composite microbial amendments, especially those combined with biochar or organic fertilizers, achieve synergistic effects in desalination, alkali reduction, and fertility improvement. (3) Core mechanisms involve organic acid-mediated pH regulation, EPS-driven ion adsorption, and plant hormone-induced stress tolerance. (4) Microbial remediation technologies have been successfully applied globally (e.g., China, Africa, Americas), resulting in average crop yield increases of 15–42% and soil salinity reductions of 30–50%. This review provides a standardized technical framework for the development and application of microbial amendments, offers theoretical support for region-specific remediation strategies, identifies key challenges (e.g., strain stability, cost control) and future research directions (e.g., gene-edited strains, smart monitoring integration), and thus facilitates the industrialization and large-scale promotion of microbial remediation technologies to address global saline–alkali soil issues.

Due to prolonged irrigation from the Yellow River, a large area of farmland in the Hetao Oasis has undergone different degrees of salinization and alkalization, leading to reduced crop yields and incapable soil for plant growth. To enhance the productivity of the farmland with saline-alkali soils, it is important to select salt-tolerant economic plant species that are capable of growing under the local climate and soil conditions in the Hetao Oasis. We conducted the experiment by planting Ziziphus jujuba var. spinose, Elaeagnus angustifolia, Hippophae rhamnoides and Lycium chinense in the Bayan Taohai Farm of the Hetao Oasis. Changes of plant growth (the survival rate, plant height, canopy, basal diameter and new branch length) and soil physicochemical properties (soil organic carbon, total carbon, total nitrogen, pH, electrical conductivity and particle size distribution) were continuously monitored during two growing seasons. Results indicated that, by the end of the first growing season, the survival rate of the Z. jujuba was less than 10%, making it unsuitable for plantation in the saline-alkali soils of the Hetao Oasis. In terms of plant growth, the E. angustifolia exhibited the highest survival rate (94.71%) and the fastest growth rate, indicating that E. angustifolia is adapted in the saline-alkali soils of the Hetao Oasis. The survival rates for L. chinense and H. rhamnoides were 86.46% and 65.64%, respectively, indicating that these species could grow in the saline-alkali soils, but at a slower rate. From the perspective of soil improvement, E. angustifolia, H. rhamnoides and L. chinense could reduce the soil pH, and E. angustifolia could significantly increase soil nutrients. In conclusion, it is not recommended to plant Z. jujuba, while the E. angustifolia is recommended as a proper economic species to be widely planted in the saline-alkali soils of the Hetao Oasis. H. rhamnoides could be selectively planted in areas with better soil conditions, and the L. chinense could be planted following soil improvement measurements. The research enhanced the effective utilization of the saline-alkali farmland and provided proper economic plant species for sustainable agriculture management in the Hetao Oasis of Inner Mongolia.