Research On The Interpolation Method Of Farmland Effective Soil Thickness

In China,the protection of cultivated land and food security has long been a national strategy.As one of the important attributes of soil,effective soil layer thickness directly restricts plant growth,vegetation coverage,soil nutrient and water migration,etc.,and seriously threatens my country’s ecological environment security.Therefore,it is very important to study the effective soil layer thickness of cultivated land.This paper selects Changji Hui Autonomous Prefecture in Xinjiang Uygur Autonomous Region as the research area,and uses Remote Sensing(RS)and Geographic Information System(GIS)technology to carry out statistical analysis and statistical analysis of 864 effective soil thickness measurement points obtained from field surveys.Spatial interpolation,4 deterministic interpolation methods(global polynomial,local polynomial,inverse distance weighting,radial basis function),4 geostatistical interpolation methods(ordinary kriging,simple kriging)by cross-validation and validation datasets The accuracy of the interpolation results of the spatial interpolation method based on the barrier factor is compared,and the optimal interpolation method is selected to reveal the spatial distribution characteristics of the effective soil layer thickness.The main research contents and conclusions are as follows:(1)The thickness of the soil effective soil layer of the cultivated land in Changji Prefecture basically obeys the normal distribution,the average value is 65.91 cm,and it is concentrated in the area of 55 cm-75 cm.The spatial variation structure of arable land reflects the uneven spatial distribution of cultivated soil.(2)Among the deterministic interpolation methods,the radial basis function(high-order surface function)has the highest interpolation accuracy,which is better than the interpolation of the global polynomial(exponent of 3),local polynomial(exponent of 1)and inverse distance weighting(exponent of 3).The accuracy is 17.38%,0.46%,and 3.13% higher on average;in the geostatistical interpolation method,the Gaussian model is selected for the semivariogram,and its fitting accuracy is higher than that of the spherical model and the exponential model;the universal Kriging interpolation has the highest accuracy,which is better than the simple gram model.Rig,ordinary kriging,and synergistic kriging are 2.79%,1.77%,and 0.99%higher on average,respectively.(3)There are areas with complex topography in the study area,and the results of traditional spatial interpolation methods have a large deviation from the actual results.Therefore,a spatial interpolation method based on barrier factors is proposed for research.The results show that the interpolation accuracy of this method is better than that of radial basis functions(high-order surface function)and universal kriging are improved by an average of 8.82% and 5.95%,respectively,which is the optimal interpolation method in this study.(4)The spatial distribution of the effective soil layer thickness of cultivated land in Changji Prefecture generally shows a trend of being higher in the north and lower in the south,higher in the west and lower in the east,and gradually decreasing from the south to the north and from the west to the east.Influencing factors such as residential areas show a decreasing and increasing trend from the center to the outside.