Effects Of Landscape Pattern On Spatial Differentiation Of Soil Elements

Natural resources in the low hills of China are abundant and have great potential for development,but with the rapid development of modern economy,the environmental pollution and ecosystem hazards in the region are becoming more and more serious,especially the soil that brings serious threats to human.Paper based on landscape ecology,environmental geochemistry,remote sensing and geographic information technology related principles,on the headwaters of the Yangtze river economic belt of typical low hilly land west region（Western Chongqing）as the experimental area,starting from the macroscopic Angle of the landscape pattern and process,utilization of the landscape types,multi-target geochemical survey data,the application of correlation analysis,regression analysis,spatial analysis and geographic detector,analysis of landscape pattern on the surface effect of the spatial differentiation of soil elements;The excavation of the spatial migration rules of soil elements under the action of landscape pattern and geographical background can provide theoretical reference and technical support for landscape planning,ecological environmental protection and soil environmental management in the hilly region with fragile ecology,important ecological location and big ecological security threat.The main findings of the thesis are as follows:（1）Major elements,heavy metal elements,Cl and C elements in the micro-basin of western Chongqing are in a normal level range.The F element of halogen elements and the N,P and S elements in basic elements vary widely and have strong spatial differentiation.The content distribution of these 4 elements is relatively dispersed,while the content distribution of other soil elements is more concentrated.Major elements in the form of oxides and some heavy metal elements appear obvious spatial aggregation phenomenon.Ca O,Mg O,K₂O,Fe₂O₃ and Cr,Ni,Zn as well as halogen element F and basic element P in the form of oxides have a high value distribution in the northwest,and a low value distribution in the vicinity of the two fold-uplifting and low-mountain forest areas,while Si O₂ is just the opposite,with a low value distribution in the northwest.The high values were distributed in the vicinity of two fold-uplifted lowland forest areas.The remaining Na₂O,Al₂O₃,heavy metal elements As,Cu,Cd,Pb,Hg,halogen element Cl and basic elements C,N,S were distributed in a relatively dispersed way.（2）The spatial distribution of soil elements is mainly influenced by lithology,landform,soil texture,geological age,soil type,temperature and precipitation.The influence of geomorphology,geological age,soil type,lithology,precipitation and temperature on soil element content space is relatively small.The multi factor interaction has stronger explanatory power on spatial distribution of soil elements.Spatial evolution of soils does not exist independently,but is the result of a combination of factors.（3）Different landscape types have different effects on soil elements.Cao,Si O₂,Ni and F are mainly affected by grassland and paddy field,Na₂O,as and C are mainly affected by grassland and garden land,Fe₂O₃,Cr and Zn are mainly affected by woodland and grassland,Cu and Cd are mainly affected by woodland and dry land,Mg O,K₂O and Hg are mainly affected by traffic land,and Mg O,K₂O and Hg are mainly affected by construction land The main elements affected by rivers are Pb,N,P and S,while Cl is mainly affected by paddy fields and garden plots.（4）The spatial heterogeneity of soil elements is mainly related to landscape fragmentation（Ci）,landscape abundance density（PRD）,dispersion and juxtaposition index（IJI）,area weighted mean patch fractal index（AWMPFD）and artificial disturbance index（V）These indices indicate that human activities and the richness and dominance of landscape types have a significant impact on the spatial differentiation of soil elements.