Effect of land use on the composition of bacterial and fungal communities in saline–sodic soils

Abstract Considerable attention has been paid to the establishment of an appropriate land use type for the reclamation of saline–sodic soils. The microbial community structures under various land use types, however, remain elusive in the western Songnen Plain of China. The aim of this study was to explore changes of bacterial and fungal abundance and community patterns under six various land use types: (a) forest, (b) sorghum, (c) paddy, (d) wetland, (e) wasteland, and (f) meadow, with a–c considered to be 'managed systems' and d–f to be 'unmanaged systems.' High‐throughput sequencing and quantitative polymerase chain reaction of bacterial 16S rRNA and fungal internal transcribed spacer rRNA genes were applied to investigate the microbial composition. The results indicated that bacterial abundance ranged from a minimum of 3.40 × 10 7 copies g −1 dry‐weight soil (d.w.s.) in sorghum to a maximum of 1.03 × 10 9 copies g −1 d.w.s. in wetland and fungal abundance ranging from 7.11 × 10 5 to 5.83 × 10 6 copies g −1 d.w.s. with lowest measured in wasteland and highest in forest, respectively. The abundance and community structures of both bacteria and fungi were similar in paddy and wetland soils, suggesting drying–rewetting alternations played a much greater role in shifting soil microbial communities than other agronomic measures (e.g., fertilization and tillage). The redundancy analysis combined with phylogenetic investigation of communities by reconstruction of the unobserved states and FUNGuild analyses indicated that bacteria predominated in nutrient cycling, whereas Ascomycota and Basidiomycota fungi were largely responsible for the restoration of aggregate stability in saline–sodic soils.