Saline-alkali soil amelioration in China: A systematic review and evidence synthesis

Ameliorating saline-alkali soils is pivotal for China’s food security, land conservation, and ecological restoration; it can unlock cropland reserves, stabilize yields, and reduce ecological risks. However, practice and policy guidance remain fragmented across scales and regions, and existing reviews seldom provide a unified framework or evidence-based rules for combining measures under specific hydrogeographic contexts. This review synthesizes knowledge on the distribution, processes, and management of saline-alkali soils and analyzes research dynamics to inform scalable practice. We retrieved records from the Web of Science Core Collection for 2006–2025, standardized terms, and retained 8423 articles. Guided by the research hotspots and thematic clusters revealed by this dataset, we evaluate four amelioration pathways within a unified multi-scale framework. Engineering measures regulate irrigation, drainage, and groundwater to set favorable water–salt conditions at field to regional scales. Agronomic practices rebuild plow-layer structure, nutrient cycling, and rhizosphere moisture. Amendment-based options supply calcium and carbon sources and microbial inputs to lower pH and ESP, promote flocculation, and activate biota. Plant-based approaches use halophytes and salt-tolerant crops to stabilize soils and enable production. In the future, efforts should strengthen predictive, mechanism-based management, standardized monitoring, model-guided prescriptions, and incentive-aligned implementation. This synthesis provides decision cues and an evidence base for efficient, green, and intelligent amelioration that supports food security, sustainable land use, and ecological restoration in China.