Fruit growing
and viticulture of South Russia

Annotation

The materials of the study of agrochemical and microbiological indicators of leached chernozem in the orchard agrocenosis and field crop rotation are presented. The peculiarities of the distribution of the main elements of plant nutrition and organic matter by layers in the upper part of the soil profile, depending on the type of cultivated crop, are revealed. As a result of the evaluation of the main groups of microorganisms of leached chernozems, 830 strains of pathogenic and conditionally pathogenic micromycetes were identified, among which Aspergillus spp. and Penicilium spp. predominate. The number of micromycetes in the studied areas differs slightly, however, in the upper layer (0-10 cm) of soils under the garden cenosis there is a sharp increase in them. It has been established that in the soils of the orchard cenosis there is a fivefold decrease in the number of bacteria in comparison with soils in the conditions of field crop rotation. The number of bacteria gradually decreases with depth. Correlations of the total number of fungi strains and colony-forming units of bacteria on the content of organic matter, nutrition elements, the total amount of salts and the reaction of the soil environment have been established. A close correlation between micromycetes and bacteria (r = 0.99), humus (r = 0.95), mobile potassium (r = 0.93) and pH (r = 0.89) was revealed in the soils of orchard cenosis. There are no close correlations in the field crop rotation. Data on the ratio of bacteria and micromycetes indicate a higher suppressiveness of soils in the conditions of field crop rotation and the depletion of the microbial pool of soils of orchard cenoses. This indicates the development of the process of soil fatigue and a decrease in the resistance of leached chernozems to phytopathogens during prolonged cultivation of an apple orchard in a monoculture.