The Effect Of Soil Microbial Community Structure On Natural Grassland Land-use Types In Bashang

Natural grassland of Bashang is a natural protective cover of the north of Hebei.Not only it provides the raw material for the development of local livestock forage,but also for the climate of Bashang provide important ecological functions.At present,the land use types in the Bashang area are concentrated in grazing,fencing and reclamation,etc.These land use types and the changes of the microbial community structure in the soil have important value for studying the quality of natural grassland,Which can directly reflect the degradation degree of natural grassland ecosystem and the soil restoration potential.These are important research index to reveal the law of natural grassland soil evolution.In the period from June to September in 2016,we gone to the National Grassland Ecosystem Observatory(Saibei Management Area)in the area of Zhangjiakou Bashang,Hebei Province.Through the three types of enclosure,grazing,reclamation,to analys the enclosure time,grazing degree and reclamation on vegetation community structure,microbial diversity and soil physical and chemical properties.The main results are as follows:(1)Through the investigation of the natural grassland in August,we found that the diversity of vegetation communities in the Bashang area were diversity.That is to say the enclosure and moderate grazing increased the diversity of grassland vegetation communities.The vegetation coverage of 5 years Enclosure is 90%.The vegetation coverage of 10 years Enclosure is 93%.The vegetation coverage of Moderate Grazing is 87%.The average of vegetation coverage is 90%.But the vegetation coverage of Heavy Grazing is 75%.The vegetation is concentrated in weeds,legumes,and grasses.The soil physical chemical properties of enclosure and grazingare were stable and they are suitable for the growth and development of vegetation.Therefore,enclosure and moderate grazing play an important role in repairing the structure and function of degraded grassland ecosystem.(2)In the study of the community structure of soil microbes of the different land-use types,it was found that the total soil microbial diversity in the different land-use types was not significantly different between the seasons,and the microbes were concentrated in about 600 genera of 35 phylum.However,under the same seasons and soil depth conditions,both the level of microbial phylum and genera,the moderate grazing soils are beneficial to improve the diversity of soil microbes in natural grassland,and the heavy grazing reduces the diversity of microbes in soil.(3)The diversity of microbes in the soil,the dominant microbes of different species in different seasons were not the same.They had their own endemic species.The dominant phylum of soil samples in June was Proteobacteria,and the dominant genera were Nitrosomonas,Arcobacter,Crenothrix,and so on.The advantage phylum of soil samples in August were Actinobacteria and Proteobacteria and the advantage genera Candidatus_Entotheonella,Solirubrobacter and other genus.(4)For the four different land-use types,we found that the enclosed and grazing soils types were beneficial to improve the Bashang soil pH of the natural grassland and increased the contents of nitrogen,phosphorus and potassium in the soil.It was found that the pH value of the enclosed and grazing soils increased or decreased regularly in the range of 8.0 ~ 9.5,which was stable at a suitable level of plant growth,both on the time scale and on the spatial scale.Soil nitrogen,phosphorus and potassium nutrient elements changed with time and soil depth,but the use of enclosure and grazing increased the nutrient content in the soil,which was more suitable for the development of natural grass than the other two.