Physical-Tomographic Characteristics and Structure of the Bacterial Community of the Agrophysical System “Germinating Roots–Pore Space of Soils” (Physical Model Experiment)
Computed tomography allows quantifying the volume of elements of the soil solids, pore space and root system. Within the framework of a special physical model experiment with cultivation of barley seedlings for 7 days and tomographic imaging at key stages, it was possible to record the dynamics of changes in the soil pore volume structure. The main goal was to quantify the structural changes in the development of the root system and their dynamics. The experiment was performed on samples of soddy-podzolic soil and chernozem, along with changes in the soil structure the changes in the structure of the microbiological community were recorded in the agrophysical system “germinating roots – pore space”. In plastic buckets with a volume of 3 cm3, models of the seedbed were created with two layers: the subseminal layer compacted to 1.2 g/cm3 and the above-seed aggregated layer with a density of 0.7–0.8 g/cm3. Seeds of barley (Hordeum vulgare L.) of the Mikhailovsky variety were placed on the boundary of the layers. Soil water content was maintained close to the field capacity. As germination progressed from 3 to 7 days, a tomographic survey and a study of the microbiological community were carried out by gas chromatography-mass spectrometry. During this period, a decrease in the tomographic porosity in the subseminal layer and a change in the number of microorganisms that mainly perform the destruction of complex carbon compounds were recorded. Tomographic and microbiological studies have shown the interconnectedness of the processes occurring during seed germination and can be used to quantify the emerging root system.