The usefulness of agricultural soil is determined by its fertility, which is influenced by physical, chemical and biological properties. Particularly important are the biological properties, shaped by microorganisms living in it and participating in the processes of decomposition of plant residues, fixation of atmospheric nitrogen and transformations of nitrogen compounds. On the other hand, soil fertility is influenced by fertility and a set of agrotechnical treatments improving its properties. Deterioration of the physical and chemical properties of the soil as a result of agricultural activity affects the rapid changes in biological properties, especially the activity of microorganisms and thus fertility. Biological properties are a sensitive indicator of changes in the soil environment. The most important agrotechnical factors influencing fertility and fertility include crop rotation, number and type of cultivation treatments and fertilization. It is largely dependent on them to increase the natural potential of the soil and obtain optimal, high-quality yields.