Physicochemical properties and fungal community characteristics of dry-cultivated alfalfa rhizosphere and non-rhizosphere soils in the sandy area of Kunlun Mountains

The potential impact of alfalfa planting on soil ecology in the Kunlun mountain sand area is unclear, therefore this study was aimed at understanding the soil ecology of this area by analyzing alfalfa in the rhizosphere and non-rhizosphere (0－40 cm) using high-throughput sequencing technology. This analysis was conducted on 20 soil samples, and 1487 operational taxonomic units (OTUs) belonging to 625 species, 384 genera, 190 families, 190 orders, 40 classes, 12 phyla were detected. It also showed the relationship between fungal community structure and diversity, as well as the physical and chemical properties of the soil. Analysis of soil physical and chemical properties indicated that the water content, total nitrogen, available nitrogen, available potassium and organic matter in the rhizosphere were significantly higher than those in the non-rhizosphere (P < 0.05). The richness and diversity of the rhizosphere soil community are lower than those of the non-rhizosphere. Ascomycota and Basidiomycota are the common dominant phylum; Gbberella, Filobasidiu and Naganishia are the common dominant genera. Cladosporium, Alternaria and Phaeomycocentrospora are the key groups of non-rhizosphere fungal communities. Naganishia, Vishniacozyma, Cystofilobasidium, Gibberella and Fusariella are the key groups of rhizosphere fungi community. Redundancy analysis showed that soil available phosphorus, potassium, nitrogen and electrical conductivity were the key factors affecting the distribution of soil fungal communities. There is a significant correlation between fungi and soil electrical conductivity and soil organic matter (P < 0.05), Naganishia, Vishniacozyma and Cystofilobasidium with soil organic matter, available potassium and available nitrogen (P < 0.05), and Alternaria and Cladosporium with soil total phosphorus, available phosphorus, soil water content and total nitrogen (P < 0.05). In conclusion, alfalfa planting in the Kunlun Mountain sand area can promote the stability of the soil ecological environment by increasing the enrichment of soil nutrients in the rhizosphere and promoting the abundance of beneficial fungi.