Novel Insight into the Change of Physicochemical Properties and Microbial Characteristics of Coastal Saline-alkali land after the construction of raised fields

Background To address the issue of land degradation caused by coastal salinization, the saline-alkali soil in the coastal area of Huanghua, Hebei, China, was selected as a pilot study to evaluate the effects of different approaches to soil improvement, especially the construction of raised fields (RFs). Methods The microbiota of various saline-alkali soils (mild, moderate, severe, and saline levels) and their adaptation to growth-limiting factors were studied. DGGE and multivariate statistical analyses were combined to analyze the structure and dominant flora of different soil bacterial communities and the correlation between soil physicochemical indexes and soil microbiota. Key Findings : A shortage of soil microbes was found in this area, with the bacterial community being dominant (more than 50% relative abundance), while the fungal community showed higher tolerance, stability, and resilience to various saline-alkali soils than the bacterial and actinomycetes communities. The contents of organic matter, available N, total salt, and Na ⁺ in the soil each exerted a great influence on the abundance of soil microbes. Notably, some mineral ions (especially orthophosphate) in the saline-alkali land could be directly utilized in the available forms by the plants grown in RFs through the symbiosis between mycorrhizal fungi and plants. Conclusion The construction of RFs and the identification of keystone bacteria that have potential adaptability to various saline-alkali environments, therefore, may be effective strategies for coastal saline-alkali land utilization as well as ecological restoration.