Study On Soil Physicochemical Properties And Bacterial Community Characteristics Of River Riparian Wetland In Inner Mongolia Grassland

Located in the Xilin River Basin of Inner Mongolia,abundant grassland resources provide favorable conditions for the development of animal husbandry.The special geographical location and unique wetland survival environment are of great significance to species protection and global climate change.In this paper,the physicochemical properties and bacterial community composition of different plant communities and microtopographical soils?hummock and hollow?in degraded and enclosed wetlands of Xilin River were analyzed.The mechanism of wetland degradation induced by grazing and the restoration mechanism of enclosed wetland were discussed from the point of view of plant-soil-microorganism.The results showed that:?1?The degradation of wetland plant community after grazing showed that the plant height and aboveground biomass decreased,the underground biomass gradually decreased with the increase of soil depth,the distribution of plant root appeared shallow layer,and the vegetation gradually recovered after enclosure.There was significant difference between enclosed and degraded sample land in plant height,and there was significant difference between enclosed and degraded sample hummock in plant aboveground biomass.?2?In vertical direction 0-100cm,the soil bulk density increased and the soil water content decreased with the increase of soil depth in the degraded sample;the bulk density decreased first and then increased and the water content increased first and then decreased with the increase of soil depth in the enclosed sample.Studied on the composition of soil particles in the sample plot:sand>silt>clay.After enclosing,the soil mechanical composition gradually changed to fine particles and pH decreased.?3?Grazing degradation hummock is more favorable to the accumulation of soil nutrients,organic carbon and trace elements.Soil salt accumulates on the surface,and the soil is salinized.In enclosed undegraded sample land,the soil nutrient content was higher in hollow and the trace element content was higher in hummock.?4?Based on the high throughput sequencing technique,Study on surface soil of sample plots were studied all 65 phylum,188 classes,197 orders,378 families,680 genera.The diversity of bacterial communities increased after grazing degradation.Proteobacteria,Actinobacteria,Firmicutes were the dominant groups of soil bacterial community.?5?The composition of soil bacterial community was different between the hummock and hollow in degraded sample,but there was no significant difference among the enclosed undegraded sample.The K,bulk density?BD?,pH,sand content had a great influence on the diversity of bacterial community in enclosed plots.The soil C/N,water content?WC?,F^-,Na⁺,and clay were positively correlated with grazing degradation hummock;grazing degradation hollow was affected by N,TOC,Mn,K⁺,SO₄^2-,NO₃^-,Cl^-,Ca²⁺.