Characteristics Of Soil Microbe In Riparian Wetland In The Lower Songhua River

The biodiversity of riparian wetland in the lower Songhua River is rich and its ecologicalfunctions are very important. In recent years, due to the intensive human activities, the naturalwetland has degraded severely and the normal developmental process of the wetland soil hasbeen changed. In this paper, the typical riparian wetland in the lower Songhua River wasselected as the research area. The characteristics of soil microbe and its controlling factorsunder different hydrological conditions and utilization were investigated to reveal the drivingmechanisms of wetland degradation processes and provide the theoretical basis for restorationof degraded natural wetland. The microbial indicators were also screened to assess thedegradation and ecological restoration of wetlands. The conclusions were listed as following:1. The soil microbial PLFAs in the lower Songhu River were mainly branch saturatedfatty acids, straight saturated fatty acids and unsaturated fatty acids. Hydroxyl fatty acids,cyclopropane fatty acids and polyunsaturated fatty acids were less. The number of bacteriawas dominant, fungi followed, and antinomycetes is the least in soil microbial community, theproportion were44.75%~52.59%,5.32%~8.21%and1.87%~5.56%respectively. Underdifferent hydrological conditions and utilization, both the microbial total PLFA amount andthe functional groups showed a significant difference.2. In different degraded wetland, there were closely relationships between soil nutrientsand soil microbial properties. And there is also significant correlation between the soil watercontent and soil microbial properties. Microbial biomass carbon, invertase, urease andphosphatase showed a significant difference in different degree.3. The main environmental factors on soil microbial community structure and activitieswere Soil water content, Total nitrogen, Total phosphorus, Rapid available phosphorus andRapid available potassium under different hydrological conditions in the natural wetland, butin different utilization types of the wetland, the main environmental factors on soil microbialcommunity structure were Soil water content, Organic carbon, Rapid available phosphorusand Rapid available potassium.4. The microbial assessment indicators of soil health in wetlands were screened bystepwise regression the principal component analysis method. The total PLFA, bacteria andmicrobial biomass carbon can be the microbial indicators of wetland soil health assessment.