| The karst peaks and depressions are the typical landforms of karsts in southwest my country.The ecological environment is fragile and the habitat heterogeneity is extremely high,which has always been the focus and difficulty of ecological management in my country.Soil is the basic condition for the evolution of the ecosystem,providing a living place for humans,plants,animals,microorganisms,etc.,and is an environmental resource that all living things need.Middle and trace elements are essential for the normal life of animals and plants,and play an important role in improving their growth,metabolism,yield and quality.Studying the spatial variability and influencing factors of trace elements in the soil will help us have a deeper understanding of the mechanism of soil formation and movement,and can better promote ecological restoration and achieve sustainable development.This study takes the subtropical karst climax community—Mulun Karst evergreen and deciduous broad-leaved mixed forest as the research object,and is based on soil sampling from a 500×500m large forest fixed dynamic monitoring plot.Analyze the spatial variability of trace elements in karst forest soils and the characteristics of habitat differences,and discuss their influencing factors,so as to provide scientific basis for guiding the restoration of ecosystems in vulnerable karst areas.The main conclusions of this study are as follows:(1)The contents of middle and trace elements in karst peak cluster depressions are different.The contents of Ca,Mg,Fe,Mn,Cu,Zn,and B are 7.87g/kg,1.49g/kg,30.24mg/kg,149.12mg/kg,1.77,respectively.mg/kg,13.54mg/kg,0.65mg/kg,the content of each element are all moderate intensity variation.After comparison,it is found that Ca,Mg,Fe,Mn,Cu,and Zn in the study area all reach the medium or above standard,and most of them are abundant,and B is relatively lacking in it.There are some significant differences in the content of the same element in different habitats,and the content is of moderate intensity variation.(2)The spatial autocorrelation analysis found that Mg,Fe,and Mn exhibited a moderate degree of spatial autocorrelation,indicating that they are mainly affected by structural factors and random factors.Other elements show strong spatial autocorrelation,indicating that soil structure is the main influencing factor.Semivariogram analysis found that each element exhibits spatial heterogeneity of different intensity,and the spatial correlation is relatively high.The scope of each element is different,and the spatial continuity is also different.Among them,the range of Zn,Ca,B is low,and the spatial continuity is poor;the range of Fe is the highest,with 733.2m,and the spatial continuity is very good.The content of Fe,Mn,and Cu is generally lower in the mountain tops,and generally higher in depressions and middle slopes.The content of Ca and Mg is lower in depressions,and higher in uphills and mountain tops.The Zn and B content distributions are different,but both show a certain spatial enrichment.(3)Spatial attributes have a great effect on the spatial variability of middle and trace elements.Site conditions and biological factors also have a great impact on the spatial variability of soil trace elements in karst forests.The exposed rate of rock is positively correlated with Ca,Mg,Zn,B,and negatively correlated with Cu;the slope direction is positively correlated with Ca,Mg,B,and negatively correlated with Fe,Mn,Cu;the slope is correlated with Ca,Mg,B It shows a positive correlation and a negative correlation with Fe,Mn,and Cu;Fe,Mn,and Cu are all negatively correlated with unevenness,and Mg,Zn,and B are positively correlated with it;altitude is positive with Ca,Mg,and Zn relationship.Ca,Mg,Zn,and B are mostly positively correlated with the species diversity index;Fe,Mn,Cu are negatively correlated with the species diversity index.Although the various medium and trace elements have a certain relationship with biological factors,they are not deeply affected by topographical factors as a whole. |
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