Spatial Variability And Scale Effects Of Soil Salinity In Typical Areas Of The Yellow River Delta

At present,the global economy has entered a stage of rapid development,and the population has increased rapidly.The contradiction between people and land has become increasingly fierce.At the same time,people's unreasonable use of land resources has led to serious land degradation,and the development situation of agricultural production is grim.Therefore,saline soil improvement has become a necessary measure.As an important land resource reserve area in China,the Yellow River Delta is seriously hindered by soil salinization Therefore,it is of great significance to master the spatial variability and scale effect of soil salinity in different time phases,multi spatial dimensions and multi-scale for improving saline soil and promoting agricultural production.In this paper,the Kenli of the Yellow River Delta is taken as the research area,and the variation characteristics of horizontal spatial differentiation and vertical profile concentration of soil salinity in spring are analyzed from three scales of region,land type and plot;the spatial heterogeneity characteristics of surface soil salinity in summer are studied from three scales of field,plot and ridge;and the spatial autocorrelation characteristics,spatial distribution characteristics and soil salinity are analyzed from the aspects of mathematical statistics characteristics,spatial autocorrelation characteristics,spatial distribution characteristics From four aspects of salinization grade,the scale effect of soil salinity differentiation in spring and summer was discussed.The main conclusions are as follows:(1)Spatial variation and scale effect of soil salinity level in springThe soil salinity in Kenli district has moderate variation intensity,and the variability,mean,extreme value and standard deviation gradually decrease with the reduction of regional scale to plot scale;except for the strong spatial autocorrelation of soil salinity in saline wasteland,the soil salinity in other scales has moderate spatial autocorrelation,which is jointly affected by random factors and structural factors;the soil salinity in regional and land type scales has moderate spatial autocorrelation The soil salt content is high in Northeast and low in southwest,and the soil salt content is distributed evenly in plot scale.With the decrease of spatial distance,soil salt content showed a decreasing trend,and soil salt grade span increased gradually.(2)Spatial differentiation and scale effect of soil salt level in summerThe results show that the soil in the study area is moderately salinized,showing medium intensity variation,and with the decrease of sampling scale,the variability of soil salinity tends to be strong,and the standard deviation increases;the spatial correlation between ridge and plot scales is strong,mainly affected by structural factors,and the field scale is medium spatial correlation,which is jointly affected by random factors and structural factors;the spatial correlation of soil salinity between ridge and plot scales is strong,which is mainly affected by structural factors The soil salt content decreased with the increase of micro topography and vegetation coverage.The spatial distribution characteristics of soil salinity in different scales are obviously different.The spatial characteristics of small scale are covered up in large scale,and there is obvious scale effect.(3)Spatial variability and scale effect of soil salinity in vertical directionRegional scale and land type scale were selected to analyze the spatial variation characteristics of soil salinity at different soil depth of 0 ? 60 cm.With the increase of soil depth,the average value,extreme value and other parameters of soil salinity increased,indicating that soil salinization became serious with the deepening of soil depth,while the coefficient of variation decreased,reflecting that the soil salinity content tended to be stable with the increase of soil depth.With the deepening of soil depth,the spatial correlation gradually increased,the influence of structural factors increased,the proportion of mild salinization grade area gradually decreased,and the proportion of severe salinization and saline soil area continued to increase,with obvious scale effect.The deeper the soil layer,the higher the soil salt content and the more serious the salinization.This study explored the spatial variation characteristics and effects of soil salinity in the whole region,main land types,plots,ridges and other multi-scale in Kenli District,and provided a theoretical basis for the study of soil salinity mechanism and the improvement of farmland land resource utilization in coastal area.