FORMATION OF THE ROOT CORN SYSTEM FOR GRAIN WITH VARIOUS SOIL PROCESSING SYSTEMS IN THE CENTRAL CAUCASUS ZONE
Questions of an in-depth study of the reaction of the root system of corn to grain, taking into account the morphological features of its fibrous structure, on the change in the agrophysical parameters of the cultivated soil layer (the density of addition and the productive moisture supply during the growing season), and, accordingly, on the crop yield under various systems main tillage is an urgent task. Object. The object of research is the root system of corn on the grain of the hybrid "Pioneer" 8688. Materials and methods. The studies were conducted in the south-eastern part of the Stavropol Territory on the southern chernozem using the traditional dump soil cultivation system and Strip-till technology. The dependence of the development of the plant root systems on the supply of productive moisture in the root layer of the soil and its density was determined by the dimensional theory method, and the intensity of filling the root space using the fractal geometry method. Results and conclusions. Mathematical modeling was performed by the dimensional method and an equation was obtained for the dependence of the intensity of root system development (degree of ripeness) S (kg / m<sup>3</sup>) for various tillage systems on factors: the density of soil addition P (kg / m<sup>3</sup>) and the reserves of productive moisture in the root layer of the soil W (m). The equation has the form: S = C (W2 / P), i.e. the development of the root system of corn for grain is in direct quadratic dependence on the supply of productive moisture and inversely on the density of the soil in the root layer, taking into account the correction coefficient C associated with the type of soil. Soil density in the spring and summer-autumn periods of vegetation was in the range of 1080 - 1150 kg / m<sup>3</sup> and 1210 - 1240 kg / m<sup>3</sup>, respectively, which falls within the optimal values of the density of addition for this crop. Moisture accumulation in the 0-1m layer in the spring is characterized by its large reserves with the Strip-till processing method compared to the traditional 0.12 m processing method, productive moisture reserves significantly decreased in the summer-autumn period, however, the tendency for a higher moisture content by Strip-till preserved, the excess is 0.04m. The analysis of the intensity of the development of the corn root system for grain under various primary tillage systems was carried out using the fractal geometry method and calculation of the length coefficient Kl and the branching coefficient of the root system Kb. The fractal dimension D of the root structure, determined by the formula D = ln Kb / ln Kl, characterizes the intensity of development of root systems as follows: the longer the branches (the less Kl) and the more of them (the higher Kb) for the root system, those. the higher the D value, the more intensive the filling of the soil space with the root system. A higher average value of the indicator D cf = 1.33 was established when processing according to the Strip-till system in comparison with traditional tillage, D cf = 1.21. Therefore, the greater the supply of productive moisture during the growing season of corn for grain and the lower the density of the soil in the root layer, with different primary tillage systems, the more intensively the soil space is filled with root systems, and therefore the higher the value of the fractal dimension D. In this regard, a tendency has been established for a higher yield of maize for grain using the Strip-till technology (4220 kg / m·10<sup>4</sup>) in comparison with the traditional technology (3960 kg / m· 10<sup>4</sup>).