Effects Of The Land Using Pattern To Soil Of Desert Grassland In Ningxia

In order to learn the effects of different land use pattern to soil of desert grassland in Ningxia,We used BIOLOG,PLFAs and T-RFLP methods, Carried out the relevant research,Which included the following aspects:firstly,the influence of different land use pattern(alfalfa, silage corn, millet, small reed communities, scoparia community)on physical,chemical and biological properties of soil;Secondly,the influence of different land use pattern on structure,function and genetic diversity of soil microbial community;Thirdly,the influence of different land use pattern on diversity of AM in soil;The result provided a scientific basis for the rational development and utilization of land in arid and semi-arid desert grassland of Ningxia.The main findings were as follows:1.Land use patterns(alfalfa, silage corn, millet)significantly increased the contents of soil organic matter,nitrogen,total nitrogen,microbial carbon,meanwhile,decreased the contents of available phosphorus and potassium.Land use patterns(alfalfa,silage corn,millet)improved the respiration rate and entropy,while,reduced the metabolic quotient of microbial community.Land use patterns(alfalfa,silage corn,millet) changed the microorganism,then,enhanced the number of soil microbial bacteria and fungi.2.The main tupes in PLFAs compositon of soil microbial community weren’t changed in the different land use patterns,but the biomass of microbial communities of advantaged phospholipid fatty acids changed significantly.Land use patterns(Alfalfa,silage corn)significantly enhanced metabolic function diversity of microbial function groups,which depended on the carbohydrates, aromatic compounds,amino compounds as the main carbon source.Microbial groups had a stonger utilization ability to aromatic compounds under millet plant pattern.Compared with silage corn, the use patterns(alfalfa,millet)increased the genetic diversity of bacteria and fungi of soil.The population structure of bacteria and fungi changed as a result.3.Land use patterns(Alfalfa,corn silage,millet)increased the species number of AMF.Glomus is the dominant genus of each treatment,each process had its own dominant species,the dominant species in each treatment showed:G.melanosporum,G.versiforme in alfalfa,G.mosseae in corn silage,G.convolutum,S.reticulata in small reed community and G.convoltum, G.melanosporum in scoparia community.Compared with natural communities,Land use patterns(alfalfa,corn silage, millet)improved Evenness at 18.95%,13.73% and 9.80%;Shannon Wiener finger 34.20%,33.33%, and 25.97%;AM spore density and AM infection rate weren’t synchronized.4.RDA analysis showed:Changing of microorganism mainly affected by soil bacterial commu nity under different land use patterns.Influenced by land use patterns,the structure and the function of soil microbial community produced differentiation in space.Microbial groups,which depended on the carbohydrates,aromatic compounds,amino compounds as the main carbon source had a posi tive correlation with nitrogen,and then,the microbial groups that depended on carbon source like carboxylic acids compounds had a positive correlation with total phosphorus.Soil AM fungal species richness and diversity index had a positive correlation with total nitrogen.AM fungal diversity,spore density and AM colonization rate in different land use patterns restricted by soil organic matter,total nitrogen and soil microbial,which depended on the polymeric compounds as the main carbon source.