CHANGES IN LAND USE TYPES AFFECT SOIL BACTERIAL COMMUNITIES AND DIVERSITIES IN THE SANJIANG PLAIN, NORTHEAST OF CHINA

This study aimed to clarify the impact of land use conversion on the composition and diversity of soil bacterial communities, and to provide a reference for the selection of scientific restoration methods for degraded wetlands in the Sanjiang Plain, Northeastern of China. In 2018, Illumina MiSeq highthroughput sequencing was used to sequence amplicons of the 16S rDNA of soil bacteria in three types of land use: natural wetlands, rice fields, and restored wetlands in the Sanjiang Plain. The diversity and function of soil bacterial communities was analyzed. The results showed that wetland converted into paddy fields caused a significant decrease (P<0.05) in the Ace, Chao1 and Shannon indices of soil bacteria, and restoration of agricultural lands into wetlands significantly increased (P<0.05) these indices. The soil bacterial community structure of natural wetland, rice field and restored wetland differed significantly (P<0.05). The detected soil bacteria represented 38 phyla, 101 classes, 251 orders, 418 families, 786 genera and 1563 species. The phyla of Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, Bacteroidetes, Nitrospirae, Latescibacteria and Verrucomicrobia were dominant in all plots, reaching a relative abundance >1%. Wetland soil bacteria have 6 types of primary functions by PICRUST2 analysis: metabolism, environmental information processing, genetic information processing, cellular processes, human diseases, and organic systems. The soil pH, content of organic carbon and total nitrogen, and the carbon to nitrogen ratio are all factors affecting the diversity of soil bacterial communities in the investigated soils. Changes in wetland land use reduce the stability of the soil ecosystem and increases the potential ecological risk of wetland degradation.