Response of soil bacterial community structure to different reclamation years of abandoned salinized farmland in arid China

In recent years, understanding the impact of reclamation of abandoned salinized field on microbial community structure is of great importance for ecosystem restoration in arid regions. The aim of this work was to investigate the effects of reclamation years on soil properties, bacterial community composition and diversity based on field sampling and llumina MiSeq sequencing. The five reclamation years are: unreclaimed salinized and reclaimed (1, 5, 10, and 15 years) fields. The results showed soil properties are significantly altered by abandoned salinized field. In particular, reclamation significantly decreased soil electrical conductivity, Cl^-, SO₄^2-, Na⁺, and Ca²⁺, during 5 years of reclamation. In addition, reclamation increased the richness and diversity of the bacterial community, except for the 1-year field soils. There was a large difference in the abundant bacterial phyla in 1-year field soils compared with other field soils. Proteobacteria were the most abundant in all of the field soils. Principal coordinates analysis showed that the abandoned and 1-year field soils exhibited specific differences in bacterial community structures compared with other field soils. Statistical analyses showed that available phosphorus, SO₄^2-, Mg²⁺, and Ca²⁺ were the main physicochemical properties affecting the soil bacterial communities. Overall, reclamation improved soil physicochemical properties and altered the structure and composition of soil bacterial communities compared with unreclaimed salinized soil.