Micromorphometric parameters of aggregates of plowed typical noneroded and severely eroded Chernozems (case study)

To create a digital soil twin, it is necessary to define and formalize as many indicators as possible reflecting its functioning in the landscape, as well as various degradation and progradation processes. The aim of the work was to identify the influence of soil properties (the content of silt, dust, sand, organic carbon (Corg) and calcium carbonate (Ccarb)) and factors of plowing and water erosion on the morphometric parameters (MP) of aggregates of arable and sub-arable layers of noneroded and severely eroded typical Chernozems (Experimental field, Kursk FARC). A significant positive correlation with the minimum diameter of aggregates was revealed for Ccarb of severely eroded Chernozems and Corg of noneroded Chernozems. Within all size classes of aggregates, the effect of the content of Corg and Ccarb and various granulometric fractions, as well as the degree of manifestation of erosive processes (on the binary scale noneroded / severely eroded) on MP was not revealed. At the same time, neither the above-mentioned soil factors nor the size class of the aggregate affect the elongation and orientation of the aggregates, while the form factor and the unevenness of the boundary decrease and increase accordingly with increasing size of the aggregates. Our study, which is innovative in many aspects, shows that the factor of water erosion has a significant effect on the physical and chemical properties of the upper horizons of plowed Chernozems. However, a detailed analysis of the MP of soil aggregates revealed that in the presence of such a powerful factor as regular agricultural processing, the factor of water erosion manifests itself only at a depth of 20–30 cm, where the influence of the anthropogenic factor weakens, and the influence of natural soil properties is stronger. At the same time, the results obtained indicate the resistance of most MP aggregates of Chernozems to water erosion if it is accompanied by annual plowing of the soil. We also showed that the unevenness of the boundary of aggregates depends more on their size than on the degree of soil erosion. Presumably, the processes of water erosion and plowing have an indirect effect on this morphometric parameter, regulating the composition of the dimensional fractions of soil aggregates.