Saline-alkali soils are widely distributed in China, affecting plant growth and sustainable development of ecosystems. Few studies have been done on the improvement of saline-alkali soils by planting Melia azedarach in phytoremediation. This study characterized the effects of planting M. azedarach on chemical properties and microbial communities in saline-alkali soils [bare (CK), bulk (BS), and rhizosphere soil (RS)]. Compared with the bare soil, planting M. azedarach lowered salt content and concentrations of extractable Na⁺, K⁺, Ca²⁺, Mg²⁺, and Cl⁻, but significantly increased organic matter, total nitrogen, total phosphorus, available phosphorus, soil urease activity, and alkaline phosphatase activity in the rhizosphere soil. High-throughput sequencing results indicated that M. azedarach increased the Chao1 index and Shannon index of soil microbial communities. The three dominant bacterial phyla were Proteobacteria, Actinobacteria and Bacteroidetes, and the three dominant fungal phyla were Ascomycota, Basidiomycota, and Glomeromycota. Redundancy analysis indicated that total phosphorus concentration and alkaline phosphatase activity significantly influenced bacterial diversity, whereas soil Ca²⁺ and Mg²⁺ concentrations were closely related to the fungal community diversity. In conclusion, planting Melia azedarach improved soil properties, increased the diversity and richness of soil microbial communities, and thus ameliorated the saline-alkali soil.

中文翻译：

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种植楝树对盐碱地土壤性质和微生物群落的影响

盐碱地在我国分布广泛，影响着植物生长和生态系统的可持续发展。通过种植楝树进行植物修复改善盐碱地的研究较少。本研究描述了在盐碱土壤 [裸露 (CK)、大块 (BS) 和根际土壤 (RS)]中种植苦木对化学性质和微生物群落的影响。与裸土相比，种植楝树降低了盐含量和可提取Na ⁺、K ⁺、Ca ²⁺、Mg ²⁺和Cl ^{- 的}浓度。,但显着增加根际土壤有机质、全氮、全磷、速效磷、土壤脲酶活性和碱性磷酸酶活性。高通量测序结果表明，紫苏提高了土壤微生物群落的Chao1指数和Shannon指数。三个优势细菌门是变形菌门、放线菌门和拟杆菌门，三个优势真菌门是子囊菌门、担子菌门和球囊菌门。冗余分析表明，总磷浓度和碱性磷酸酶活性显着影响细菌多样性，而土壤Ca ²⁺和Mg ²⁺浓度与真菌群落多样性密切相关。总之，种植楝树改善了土壤性质，增加了土壤微生物群落的多样性和丰富度，从而改善了盐碱地土壤。