Study On Vegetation Biomass And Soil Physical And Chemical Properties In Northern Yinshan Desert

Desert vegetation is an important part of desert ecosystem,which plays an important role in maintaining ecosystem stability,preventing wind and fixing sand,and protecting environment.Taking the desert vegetation and soil in the north of Yinshan Mountain as the research object,this thesis uses the method of quadrat survey to reveal the variation law of biomass of different desert shrubs and the relationship between biomass and soil physical and chemical properties,so as to provide theoretical basis for the reasonable protection and utilization of desert plant resources in the north of Yinshan Mountain,and provide data support for drawing the desert vegetation map of China and establishing the desert vegetation and soil information database of China.The results show that:(1)The shrub desert in the north of Yinshan Mountain can be divided into 12 formations:Form.Sarcozygium xanthoxylon,Form.Nitraria sphaerocarpa,Form.Potaninia mongolica,Form.Caragana korshinskii,Form.Caragana tibetica,Form.Reaumuria songarica,Form.Ceratoides latens,Form.Salsola passerina,Form.Artemisia ordosica,Form.Nitraria tangutorum,Form Caragana stenophylla and Form.Oxytropis aciphylla;Among them,Reaumuria songarica,Salsola passerina,Caragana korshinskii and Caragana stenophylla formations were the main groups,with 29-34sample plots,accounting for 51.04%of the total number of the investigated groups;Form.Sarcozygium xanthoxylon,Nitraria tangutorum,Oxytropis aciphylla and Form.Artemisia ordosica were the second,with 17-19 sample plots,accounting for 29.46%of the total number of the investigated groups;Nitraria sphaerocarpa,Potaninia mongolica,Caragana tibetica and Ceratoides latens were the second The number of sample plots ranged from 11to 13,accounting for 19.50%of the total number of shrubs.(2)With the increase of altitude in the north of Yinshan Mountain,the biomass allocation of constructive species in Sarcozygium xanthoxylon showed an increasing decreasing increasing trend;The results showed that the biomass allocation trend of the constructive species in the Nitraria sphaerocarpa?Caragana tibetica?Caragana korshinskii?Ceratoides latens?Salsola passerina?Nitraria tangutorum?Reaumuria songarica and Caragana stenophylla increased and decreased;the biomass allocation trend of the constructive species in the Potaninia mongolica was decreasing increasing;the biomass allocation of Caragana stenophylla constructive species increased gradually;the biomass of the species in the Oxytropis aciphylla was basically stable,and there was no obvious change.(3)From the 15 indexes of plant height(H),long axis of crown(D₁),short axis of crown(D₂),crown area(s),Moisture content H²?HD₁?HD₂?derived from the combination of the above variables,one index was selected as the best independent variable to establish the optimal prediction model of aboveground biomass of shrub in plant formation.in which H was the best independent variable for Sarcozygium xanthoxylon and Artemisia ordosica.D₂was the best independent variable for Nitraria sphaerocarpa?Ceratoides latens and Oxytropis aciphylla,D₁was the best independent variable for Potaninia mongolica and Caragana stenophylla,D₂S was the best independent variable for Caragana korshinskii and Caragana tibetica,D₁D₂was the best independent variable for Reaumuria songarica,D₁H²was the best independent variable for Salsola Salsola and D₁H²was the best independent variable for Nitraria tangutorum.(4)There were significant differences between the underground and aboveground biomass of herbaceous plants in different formations.The underground biomass of herbaceous plants was negatively correlated with the soil depth,that is,with the increase of soil depth,the underground biomass content of herbaceous plants was lower.(5)There were significant differences in soil physical and chemical properties among different plant groups.The total phosphorus content of Artemisia ordosica,Reaumuria songarica and Caragana stenophylla was higher,followed by Nitraria tangutorum,Caragana korshinskii,Potaninia mongolica,Nitraria sphaerocarpa and Salsola passerina,and Oxytropis aciphylla was lower;The soil organic matter content of Caragana korshinskii,Sarcozygium xanthoxylon,Artemisia ordosica,Reaumuria songarica and Oxytropis aciphylla was higher,followed by Caragana stenophylla and Nitraria sphaerocarpa,and Salsola passerina was lower;The soil total nitrogen content of Caragana stenophylla,Caragana korshinskiii,Sarcozygium xanthoxylon and Oxytropis aciphylla was higher than that of Artemisia ordosica,Nitraria tangutorum,Reaumuria songarica,Caragana tibetica,etc;The results showed that the soil moisture content of Nitraria sphaerocarpa,Potaninia mongolica and Caragana stenophylla was higher,followed by Artemisia ordosica and Sarcozygium xanthoxylon,and Caragana korshinskii was lower;The soil bulk density of Salsola passerina formation was the highest,followed by Caragana stenophylla and Sarcozygium xanthoxylon formation,and Caragana tibetica formation was the lowest;The soil porosity of Caragana stenophylla and Ceratoides latens group was higher than that of Potaninia mongolica and Nitraria sphaerocarpa group,and that of Oxytropis aciphylla group was lower.(6)There is a correlation between soil physical and chemical properties and herbaceous biomass in different groups.The biomass of Caragana korshinskii,Sarcozygium xanthoxylon,Nitraria sphaerocarpa,Ceratoides latens and Oxytropis aciphylla was positively correlated with the total phosphorus content of soil;The biomass of Caragana korshinskii,Reaumuria songarica,Salsola passerina,Ceratoides latens and Artemisia ordosica was positively correlated with soil organic matter;The biomass of herbage of Sarcozygium xanthoxylon,Reaumuria songarica,Salsola passerina,Potaninia mongolica,Caragana tibetica and Caragana stenophylla was positively correlated with the total nitrogen content of soil;The biomass of herbage of Sarcozygium xanthoxylon,Caragana tibetica,Oxytropis aciphylla and its average water content were positively correlated;The biomass of grass in the Caragana tibetica,Nitraria tangutorum and Caragana stenophylla was positively correlated with the average porosity of soil.(7)The aboveground biomass of constructive species in different formations was negatively correlated with the height,coverage and density of associated shrub species,positively correlated with the thickness of wet soil layer,and negatively correlated with the thickness of calcareous layer.