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In order to figure out spatial heterogeneity characteristics of soil aggregates in the agro-pastoral crisscross sandstorm area at the northern piedmont of Yinshan Mountain, in this paper we explored the spatial heterogeneity of aggregates composition and stability of surface soil (0-20cm) in Wuchuan County with the help of geographic information system (GIS) and remote sensing technology, combining with the analysis method of classical statistics and geostatistics. The results showed that in the study area, the aggregates content of 0.053-0.25mm was the highest, and the 0.053mm aggregates was the smallest, meanwhile the aggregates composition and stability index of each grain size showed moderate variability. The optimal fitting model for <7mm aggregates was linear model, and the sample data had no spatial correlation. 1-7mm, 0.053-0.25mm, <0.053mm aggregates and MWD were best fitting Gaussian model, Gaussian model, spherical model and Gaussian model respectively, and the sample data had strong spatial autocorrelation, while 0.5-1mm, 0.25- 0.5mm and GMD were best fitting Spherical model, Gaussian model and Gaussian model respectively, and the sample data had moderate spatial autocorrelation. In the eastern part of the test site, the content of <0.25mm aggregates is higher, the soil stability is higher, and the soil erosion resistance is stronger. The results of correlation analysis showed that the higher the content of aggregates <0.5mm, the higher the value of MWD and GMD, the better the stability of soil, and the stronger the anti-erosion ability. In the subsequent land management, we should apply reasonable tillage and fertilization measure, especially the rational use of organic fertilizer according to the actual condition of the local farmland ecological environment. The intention is that given full play to the role of soil organic binder and form well soil aggregates structure. Finally, it can provide a theoretical guidance for efficient utilization of farmland and sustainable development of agriculture in this area.
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