A Markov-based model for predicting the development trend of soil microbial communities in saline-alkali land in Wudi County

In October 2015, different salinity soils were collected in the coastal area of Wudi, Shandong, China. The soil microbial community composition, soil catalase, urease activity, and soil physicochemical properties were studied. The results showed that Nitrospira was dominant in the bacterial community, and it was the most related to total potassium. Cladosporium and Fusarium accounted for the dominant fungal community, and urease, total nitrogen, and Cladosporium were the most relevant. At the same time, urease and Fusarium are the most relevant. The species composition of bacterial and fungal communities in the top soil of each saline-alkali soil is the most abundant, and the degree of homogeneity is high. The activities of catalase in soils with heavy, moderate, and light salinity were 3.52 to 4.56, 3.08 to 4.61, and 5.81 to 6.91mL center dot g-1, respectively. Catalase activity all of them are characterized by gradual increase with soil depth; soil total potassium is directly related to catalase, pH, organic matter, total nitrogen, and total phosphorus are indirectly related to catalase by total potassium. The urease activities of the saline-alkalinity soils were 0.04-0.52, 0.08-1.07, and 0.27-8.21mg center dot g-1, respectively, and the urease activity gradually decreased as the soil depth increased. Small trend; soil total nitrogen is directly related to urease, pH, organic matter and total potassium are indirectly related to urease through total nitrogen. The CCA ranking showed that total phosphorus had the greatest impact on bacterial communities, while urease had the greatest impact on the fungal community.