Relevance. The combined method of the main tillage, using certain methods of influence on the cultivated layer, forms a certain soil density. During the growing season of corn for grain, this indicator changes depending on the seasonal soil moisture and the intensity of the development of the root system of the plant, which is ultimately related to the yield of the crop. Material and method. The objects of research are two systems of basic tillage for corn for grain according to the predecessor winter wheat in the zone of unstable moisture of the Stavropol Territory using a dump and a combined method of basic tillage with elements of Strip-till technology. Soil: southern calcareous chernozem, slightly humus. The functional dependence of soil density on the supply of productive moisture and the intensity of development of the root system of grain corn was established by the method of the theory of dimensions. The method of fractal geometry was used to determine the degree of filling the soil space with root systems of grain corn under various systems of basic tillage.Results and Conclusions. It was found that the density of the soil is in direct functional dependence on the supply of productive moisture in the cultivated soil layer and the intensity of development of plant roots. The soil density during the seeding and flowering periods is higher by the Strip-till technology in comparison with the traditional one on average over the years by 0.02 g / cm3 and 0.03 g / cm3, respectively, and the moisture reserve in the spring period with Strip-till is 12 mm. The intensity of development of the root system according to the indicator D with the Strip-till system (1.58) by 0.31 units, more than with recommended processing (D = 1.27). The yield of corn for grain using the Strip-till technology is on average 0.22 t / g higher than with the recommended one, at a lower cost by 2395 rubles / ha.