Impacts of vegetation restoration on soil physicochemical properties, bacterial communities, and metabolites in newly reclaimed croplands

Abstract. To find one suitable vegetation restoration type as a good means of restoring newly reclaimed croplands in subtropical of China. This study investigated the effect of vegetables, corn, and peach in soil properties, bacterial communities, and metabolites of newly reclaimed lands after three years restoration. Results from this study indicated that soil physicochemical properties were differentially affected by vegetation restoration of three different plants, while the effect depends on both the vegetation types and the kind of soil parameters. Indeed, the pH, soil bulk density (SBD), soil organic matter (SOM) and total nitrogen (TN) were generally unaffected except a significant reduction in SBD (13.97 %) and SOM (35.41 %) by vegetable and peach, respectively. However, three different plants significantly increased the available phosphorus (AP) (75.03–143.02 %), available potassium (AK) (154.90 % and 103.93 %) and microbial biomass carbon (MBC) (37.71–144.93 %), with the greatest increase by vegetable relative to the control except a significant reduction in the AK (41.73 %) by peach. Furthermore, the analysis of 16S rRNA gene high-throughput sequencing revealed that the vegetation of three plants increased the relative abundances (RAs) of soil bacterial phyla and genera with 6.21–10.54 % increase in operational taxonomic units (OTUs), 6.22–10.53 % increase in Chao1 and 2.30–3.11 % increase in Shannon indices, while redundancy discriminant analysis (RDA) revealed that the change of soil properties were highly related to the variation in bacterial community composition. In addition, 130 significantly differential metabolites (SDMs) that belong to organic acid, amino acid, heterocyclic compounds between vegetable and the control were identified based on liquid chromatography-mass spectrometry (LC-MS) analysis, while the top 20 SDMs were highly correlated with the 7 enriched bacterial genera. Overall, the results showed that the vegetation of three plants, in particular vegetable can ameliorate soil quality of newly reclaimed croplands by improving soil chemical properties, and increasing the richness and complexity of bacterial community structure, as well as specific bacterial genus and metabolites.