The numbers tell a striking story of accelerating urgency. Of the 554 publications analyzed, 343 — or 61.9 percent — appeared between 2019 and 2025 alone, with 102 published in 2025, the peak year. Publication output was low and intermittent in the 1980s and 1990s, increased gradually after 2000, and rose sharply after 2019. China dominated the research landscape, contributing 297 publications, followed by the United States with 60, Australia with 56, India with 25, and Spain with 23. The leading journals included Science of the Total Environment, Agronomy, Ecological Engineering, and Land Degradation and Development, reflecting the interdisciplinary nature of a field that spans environmental science, agronomy, and restoration ecology.

To build the corpus, the researchers searched the Web of Science Core Collection and Scopus databases, completing both searches by August 9, 2026. The Web of Science export contained 445 records; removing 2 duplicates left 443. Of the 590 Scopus records, 389 matched the Web of Science set and 201 were additional records, producing a merged set of 644 unique records. Applying the publication-year criterion removed 90 records, leaving the analytical corpus of 554 publications: 386 from Web of Science and 168 additional records from Scopus. Cross-database consistency was remarkably high — annual output showed a Pearson correlation of 0.984, and country rankings showed a Spearman correlation of 0.917 — indicating that the patterns observed were robust regardless of which database was used.

The keyword network, built from 386 Web of Science records, contained 120 terms and 951 edges. Greedy modularity analysis identified four thematic communities with a modularity score of 0.279: vegetation and ecological restoration (48 terms), plant salt-stress responses and tolerance (37 terms), soil reclamation and amendments (27 terms), and soil, nutrients, and microbial associations (8 terms). Louvain clustering identified five communities with a similar modularity of 0.280, and the two partitions showed moderate agreement with an adjusted Rand index of 0.620. Sensitivity analyses varying the minimum term frequency, vocabulary size, and edge threshold confirmed that community partitions were relatively stable at minimum term frequencies of four and six records, though changes in the edge threshold produced more pronounced differences in community number and network connectivity.

Temporal analysis of keyword medians revealed a striking shift in research emphasis. The median publication year was 2014 for both gypsum and red mud — traditional reclamation materials — and 2016 for reclamation itself. By contrast, ecological restoration and diversity both had a median year of 2022, and phytoremediation had a median of 2023.5. This pattern suggests the field has moved from a focus on chemical and physical soil treatments toward ecological approaches that harness living systems. Dictionary-based text analysis of all 554 records confirmed this: plant establishment and growth terms appeared in 340 records, and high pH and sodicity terms in 336, making these the two most frequent of eight text categories. Soil amendment and reclamation terms occurred in 171 records, rhizosphere and microbial terms in 160, physiological tolerance in 123, community recovery in 118, water–salt management in 116, and phytoremediation and halophyte terms in 103.

At the heart of the analysis lies a concept the authors call the establishment bottleneck. Salt-affected soils impose combined osmotic, ionic, chemical, physical, and hydrological constraints on the root zone, and their effects are especially pronounced during germination and early growth, when small root systems and limited reserves restrict water uptake and ion regulation. Rising salinity initially restricts seed water uptake and germination and inhibits root elongation and leaf expansion. Prolonged exposure can lead to sodium and chloride accumulation in plant tissues, accelerating leaf senescence and reducing photosynthetic capacity. Combined salinity and alkalinity generally suppress germination and post-stress recovery more strongly than either stress alone. Critically, salinity tolerance measured only in mature plants cannot predict population recruitment, persistent vegetation cover, or ecosystem recovery — a finding that challenges how restoration suitability has traditionally been assessed.

The authors stress that salinity, alkalinity, and sodicity are distinct stresses requiring different management responses. Salinity is commonly assessed by electrical conductivity, most often that of the saturated paste extract, reflecting the overall concentration of soluble salts and the associated osmotic and specific-ion stresses. Alkaline stress should be assessed using pH together with carbonate and bicarbonate concentrations, since high pH can alter phosphorus speciation and reduce iron, zinc, and manganese availability. Sodicity, characterized by exchangeable sodium percentage, disperses clay, promotes surface crusting, and reduces infiltration and aeration. These constraints commonly coexist in the field, and their sequencing matters enormously: in saline–sodic soils, intensive leaching before exchangeable sodium is addressed may expose or worsen clay dispersion and infiltration limitations as soluble-salt concentrations decline. Gypsum presents a particular paradox — it can reduce sodicity while initially increasing dissolved salts, meaning electrical conductivity may rise even as exchangeable sodium percentage falls.

Plant-mediated restoration offers a pathway that goes beyond simply adding tolerant species. Established plants can redistribute salts through uptake, exclusion, or secretion and modify the root zone through litter inputs, shading, and root channels. Roots influence rhizosphere pH, carbon supply, aggregate formation, and microbial recruitment, while canopy cover can reduce erosion and evaporation-driven upward salt movement. In calcareous sodic soils, plants may even promote root-zone calcite dissolution, facilitating the displacement and removal of exchangeable sodium. Amendments play complementary roles: calcium-containing materials such as gypsum primarily improve infiltration in sodic soils, while manure, compost, and crop residues increase carbon inputs and improve aggregate stability, nutrient availability, and microbial habitat. Biochar can alter soil pore structure and water and nutrient retention, but a meta-analysis found it reduced soil salinity with no significant overall effect on soil pH — evidence that a single material generally addresses only some of the constraints present at a site.

Rhizosphere and microbial processes offer a third management pathway whose effects depend on site conditions. Microbial inoculation, mycorrhizal symbioses, and plant growth-promoting bacteria can enhance nutrient acquisition, root development, and stress tolerance, but their effectiveness depends on the host plant, salinity, pH, water availability, organic substrates, and persistence under field conditions. Root exudates can recruit rhizosphere bacteria; legumes can alter nutrient availability and microbial community composition; and amendments can influence microbially mediated carbon and nitrogen cycling. Soil enzyme activities can serve as early indicators of responses to amelioration, whereas long-term restoration involves gradual changes in the physical, chemical, and biological properties of soil. Microbial measures should therefore be applied according to the combination of stresses, plant requirements, and rhizosphere conditions at the target site, in conjunction with soil amelioration and water and salinity management.

Synthesizing these findings, the authors propose a conceptual five-step adaptive management framework — Diagnose, Match, Sequence, Monitor, and Adapt — for testing at restoration sites. Diagnosis should distinguish the dominant constraint from other stresses, measuring electrical conductivity, pH, exchangeable sodium percentage or sodium adsorption ratio, soil texture, and carbonate and bicarbonate status alongside irrigation-water quality, drainage conditions, and groundwater depth. The Match step selects species or functional groups for their intended role, whether establishing pioneer cover, stabilizing soil, supporting phytoremediation, or restoring communities. The Sequence step concerns the order and timing of interventions: a pathway for water and salt removal should be established before intensive leaching where drainage is inadequate, and calcium-containing amendments should be applied before or together with leaching where sodicity restricts infiltration. Monitoring should assess plant establishment and soil recovery together, tracking germination, survival, root development, vegetation cover, and community composition alongside electrical conductivity, pH, exchangeable sodium percentage, water content, groundwater depth, organic carbon, and aggregate stability. The Adapt step uses monitoring results to revise management, with persistently elevated root-zone salinity, a rising groundwater table, declining plant survival, or renewed soil-structural deterioration prompting reassessment. The authors emphasize that the framework and its decision rules have yet to be empirically validated — controlled field comparisons and long-term monitoring are needed to assess their benefits for plant establishment and sustained recovery. They also propose a detailed reporting checklist covering site and climate, stress characterization, interventions, plant establishment, functional responses, soil recovery, rhizosphere and microbial measures, and monitoring design, arguing that consistent units, clear baselines, and repeated measurements are essential for comparing intervention combinations and timing under different stresses. As climate change is expected to intensify primary salinization in some drylands and irrigation–drainage imbalances continue to cause secondary salinization, the stakes of getting this playbook right could not be higher.

Subject of Research: Environmental Science

Article Title: From salinity, alkalinity, and sodicity to vegetation recovery: a bibliometric analysis and thematic mapping of plant responses and restoration strategies

Article References: Chen, X., Hong, Q., Zhang, W., Wang, Y., Liu, C., & Liu, X. (2026). From salinity, alkalinity, and sodicity to vegetation recovery: a bibliometric analysis and thematic mapping of plant responses and restoration strategies. Frontiers in Environmental Science, 14, Article 1979449. https://doi.org/10.3389/fenvs.2026.1979449

Image Credits: AI Generated

DOI: 10.3389/fenvs.2026.1979449

Keywords: soil salinity, vegetation restoration, bibliometrics, soil reclamation, plant physiology, ecosystem restoration, salinity, alkalinity, sodicity, vegetation, recovery, bibliometric