Quantitative Characteristics of the Microstructure of Typical Chernozems under Different Agricultural Technologies

The methodological possibilities of micromorphological soil research to analyze digital images of soil thin sections at a quantitative level are presented in this study. A new software Thixomet Pro has been tested for quantitative micromorphological study of soil thin sections from the surface horizons of a Haplic Chernozem. Soil samples for preparing thin sections were collected on the territory of a field experiment for assessing the impact of agricultural technologies in grain crop rotation on soil properties in Kursk oblast, Russia. In the field experiment, conventional tillage and no-till (direct seeding) technologies were compared. Soil sampling was carried out in two replicates from a depth of 10-15 cm. The analysis of thin sections revealed the variability of microstructure of Haplic Chernozem in the size, shape, and orientation of aggregates associated with used agricultural technologies in grain crop rotation. Soil aggregates under no-till are generally larger compared to the aggregates under conventional tillage. This is noted for all levels of aggregate diameters: minimum, medium, and maximum. In trials with direct seeding, agronomically valuable aggregates typical of the structure of virgin soils predominate. The aggregates formed in the no-till soil are less rounded and isometric than those in the soil under conventional tillage, and the proportion of subhorizontal aggregates is higher (54.3 and 34.1%, respectively), which favors water retention in the surface horizon.