Influences of land reclamation on soil bacterial communities of abandoned salt pans in the Yellow River Delta

Abstract

AbstractReclamation has been widely accepted as a means to restore abandoned lands. Most studies focused on the improvement of land reclamation explore soil nutrients and microbial activities. However, the effects of time since reclamation on bacterial communities of abandoned salt pans are still unclear. The object of our study are is to: (i) assess the successional change of soil physicochemical properties and bacterial communities in abandoned salt pans with different reclamation histories; and (ii) determine the main limiting factors on the improvement of soil quality in abandoned salt pans. The soils in farmland [reclamation time for blank (RTBL)] and six abandoned salt pans with 1 year (RT1), 2 years (RT2), 3 years (RT3), 4 years (RT4), 8 years (RT8), and 9 years (RT9) since reclamation were sampled to investigate the temporal variation of soil properties, heavy metal content, bacterial community composition, and diversity. Results showed that the soil bulk density (BD), total dissolved salt and median particle size (MMAD) decreased with the increase of time since reclamation, while soil nutrients (soil organic matter, total nitrogen, available phosphorus, available potassium) showed an opposite trend. The bacterial α‐diversity increased first, then decreased. Land reclamation enhanced the relative abundances of Acidobacteria, Chloroflexi, and Actinobacteria but reduced the relative abundances of Proteobacteria, Gemmatimonadetes, and Bacteroidetes. Compared with RTBL, the soil nutrients and bacterial community structure in RT1, RT2, RT3, and RT4 showed a significant difference. After 8‐9 years (RT8 and RT9) of reclamation, the soil nutrients and bacterial community structure in reclaimed abandoned salt pans showed RTBL. Therefore, time since reclamation is a vital driving force for restoring soil physicochemical properties and bacterial communities in abandoned salt pans.