Relationship Between The Slope Micro-topography And Vegetation Characteristics On The Loess Area Of Northern Shaanxi

The loess area in northern Shaanxi is characterized by gullies,ravines with few rainfalls,it has poor natural conditions and fragile ecological environment,so research how to rehabilitate the vegetation on difficult sites has a great significance to the semi-arid loess area of northern Shaanxi Province.Affected by soil erosion and human activities,five types of micro-topography,including collapse,platform,scarp,shallow gully,gully and the undisturbed slope,are widely distributed on the slopes of this area,which affect the infiltration process of rainfall confluence and infiltration,resulting in different soil moisture on the slopes.Qualitative,which in turn affects plant growth and community structure and its succession process.Therefore,this paper was conducted a study in the Hegou Watershed of Wuqi County,Shaanxi Province,to compare and analyze the heterogeneous characteristics of plant communities and soil moisture on the slope of the micro-topography under different landform factors,to reveal the differences of vegetation communities structure and soil moisture in different micro-topography,and discuss the coupling relationship between the vegetation characteristics on the micro topography and soil moisture of the micro topography,study the relationship between the micro-topography and vegetation characteristics in the loess area,and clarify the effect of the slope micro-topography on ecological restoration,with a view to the construction of near-natural vegetation in the loess area of northern Shaanxi Rebuild provides reference.After investigation and research,the results of the research are as follows:(1)The total area of micro-topography on the slope of the study area accounts for about one-third of the total slope area.Among them,the number and area occupied by the gully are the largest,and the scarp are the lowest.Micro-topography factors have a significant influence on the vegetation characteristics on slopes in the loess area.(2)There are obvious differences between the various quantitative characteristics of vegetation communities in different micro-topography,mostly forming herbaceous communities with Artemisia sacrorum and Imperata cylindrica as the dominant species.The number of species,coverage,average height,and biomass of micro-topographic plant communities is better than that of the undisturbed slope,and the difference between the gully,shallow gully,collapse and the undisturbed slope showed the most significant difference.When artificial vegetation construction is carried out in the loess area of northern Shaanxi,plant arrangements should be carried out according to the characteristics of the plant communities of different micro-topography.(3)During the monitoring period,there was a significant positive auto-correlation between the soil moisture content of each layer in the 0-160 cm soil layer in each mocrotopography during the monitoring preiod,and the soil moisture content in the early stage would have an impact on the soil moisture content in the later stage.The soil moisture content showed different changing trends with time in different depths of soil layers.Among them,the soil moisture of the scarp and the undisturbed slope showed a significant increasing trend in different depths of soil layers.The soil moisture content of the collapsed and the undisturbed slopes showed a slight increasing trend in different depths of soil.The soil moisture content of shallow gully and gully showed a slight decreasing trend in the surface soil and deep soil layers.(4)Among the mean values of soil moisture content in various types of micro-topography,the soil moisture content of different micro-topography is: gully > shallow gully > platform > the undisturbed slope > collapse > scarp.In general,the soil moisture trend in the vertical direction showed an "S" shape,and the variation of soil moisture was larger in the shallow soil layer and smaller in the deep soil layer.(5)The soil moisture content of various types of micro-topography in different soil layers from0-160 cm has some differences,the soil moisture condition of collapse in the soil layer above 60 cm is better,while the soil moisture content of shallow gully,platform and scarp in this soil layer is less different from the undisturbed slope;the soil moisture content of gully in the soil layer from 80 cm to160cm is most significantly different from other micro-topography and the undisturbed slope,and the deep soil moisture condition of other types of micro-topography also shows significant advantage compared with the undisturbed slope.(6)Soil moisture content is significantly correlated with the number and diversity of plant communities,and the soil moisture content in the soil regulating layer and weak utilization layer plays a key role in the growth and succession of plant communities.(7)There is a certain coupling relationship between plant community characteristics and soil moisture content in various types of micro-topography,among which the coupling relationship between Margalef richness index and soil moisture is the strongest and has a strong mutual influence.The micro-topography will lead to spatial differentiation in the coupling relationship between plant community characteristics and soil moisture,so the coupling relationship between soil moisture and plant community characteristics of different micro-topography should be used as a reference basis when constructing artificial vegetation in the loess area of northern Shaanxi.