Effects of soil physicochemical properties on microbial communities in different ecological niches in coastal area

Soil salinization is one of worldwide problems and is especially serious in coastal areas featuring saline-alkali soils. In the process of natural biological succession, such saline-alkali soils reach a point where they can be ameliorated by planting resistant crops such as Jerusalem artichoke (Helianthus tuberosus L.) that could change soil properties in the rhizosphere. In this study conducted in Dafeng District, near Yancheng City, Jiangsu Province, at the Yellow Sea coast (N 32°56′-33°36′, E 120°13′-120°56′), soil physicochemical properties, enzymatic activities and microbial communities were characterized in the bare and rhizosphere soil from the areas growing Spartina anglica Hubb. or Suaeda glauca Bunge/Imperata cylindrica L. Beauv. or Jerusalem artichoke compared with the corresponding unplanted soils. The results showed that soil pH and salinity in the bare soil of Jerusalem artichoke planting area as well as unplanted control soil were lower, and available phosphorus and alkaline phosphatase were higher, than in the other soils. For soil microbial community, Proteobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Acidobacteria and Gemmatimonadetes were the dominant phyla in all samples. The number of Operational Taxonomic Units (OTUs) was higher in the rhizosphere soil of Jerusalem artichoke than the bare and unplanted soil in the same area. The results suggested that planting Jerusalem artichoke improved the soil physicochemical properties and increased microbial diversity.