Study On The Distribution Of Soil PhysicochemicaProperties And Vegetation In Subtropical Evergreen And DeciduousBroa Dleaved Mixed Forest In Cenwanglaoshan

Taking the typical subtropical evergreen and deciduous broad-leaved mixed forest of Cenwang Laoshan as the research object,through dense sampling(n=200),the distribution characteristics of soil physical and chemical properties in vertical profile,horizontal direction and spatial pattern were explored,and the plant diversity was also explored.Correlative analysis was conducted to provide basic data and scientific sampling methods for the study of soil and plants in the Wangwang Laoshan Nature Reserve;to better understand the spatial distribution of soil in the subtropical evergreen-deciduous broad-leaved mixed forest,and to further explore It provides basic data on organic carbon and soil nutrient content in the area.The results of the study are as follows:1.Characteristics of soil physicochemical propertiesIn the vertical section direction,soil water content,bulk density,pH value,and total potassium content increase with vertical profile deepening,and organic matter,total nitrogen,and total phosphorus decrease with increasing vertical profile.Soil water content,pH,organic matter,total nitrogen,total phosphorus,and total potassium have extremely significant correlations with the AB layer.The AB distribution of soil water content,bulk density,organic matter,total nitrogen,total phosphorus,and total potassium all reached mid-high degree variations.Values appear weakly distributed in the AB layer.In the horizontal direction,the soil physicochemical properties are larger in the south slope,valley,and ridge,and the north slope is smaller,indicating that the slope direction has an influence on the physical and chemical properties of the soil.The correlation between soil physicochemical properties and topographic factors revealed that slope had a greater influence on soil physical and chemical properties.In terms of spatial distribution,soil water content,bulk density,organic matter,total nitrogen distribution decreased from the peak region to the periphery;soil pH and total phosphorus decreased from southwest to northeast of the plot;total potassium content decreased from west to east.2.Plant diversityThe survey of plant sites in the plots showed that there were 4561 trees with DBH ≥ 1cm in the plot,belonging to 27 families,59 genera,and 130 species,including 398 deciduous trees belonging to 10 families,11 genuses and 11 species,accounting for 8.7%of the individuals.The number of subjects accounted for 37%,accounting for 16.9%of the genera,accounting for 8.4%of the species.The frequency of dominant species was analyzed and it was found that the distribution frequency of dominant species dominant species was significantly different among the plots,mainly distributed in the middle and northeast of the plot.The study on plant diversity indices in plots found that the Gleason index was 5.361.11,the Margalef index was 6.100.90,the Shannon-Weaner index was 2.760.23,the Peilou index was 0.800.06,and the dominance was Simpson.The index is 0.110.05.Among them,Gleason index,Margalef index,Simpson index reached moderate variation,and Shannon-Weaner index and Peilou index showed weak variation.3.The relationship between soil physical and chemical properties and plant diversity① Correlation between soil physical and chemical properties and plant diversity indexThe richness index was positively correlated with organic matter and total nitrogen,and negatively correlated with total phosphorus,total potassium,pH,water content,and soil bulk density.The diversity Shannon-Weaner index was positively correlated with organic matter content and total nitrogen,and negatively correlated with total phosphorus,total potassium,pH,water content,and soil bulk density.The uniformity peilou index was positively correlated with total nitrogen,total phosphorus,total potassium,and pH,and negatively correlated with organic matter content,soil water content,and soil bulk density.The dominance Simpson index was positively correlated with total phosphorus,total potassium,pH,organic matter content,soil water content,and soil bulk density,and negatively correlated with total nitrogen.②Soil physicochemical properties and distribution frequency of dominant speciesRhododendron simiarum and Dipentodon sinicus had weak correlation with soil physical and chemical properties.Beilschmiedia fordii had extremely significant correlation with soil bulk density,water content,and total nitrogen content.Lithocarpus hanceiwas significantly associated with soil water content and total phosphorus content,and was highly significantly associated with PH.Castanopsis eyrei were significantly associated with water content,pH,total phosphorus,and total potassium.