LOCAL CONTOURS OF DRIP SOIL MOISTURING, FORMED ON SLOPING LANDS
Introduction. Well-known experimental studies have established the facts of the influence of slopes of the earth's surface of drip-moistened slope lands on the location, shape and size of local moisture contours formed in the soil space, but there is no generally accepted method for predicting them. This circumstance is explained by the absence of an experimental base that is necessary for generalizations, the complexity and multifactorial nature of the contour formation process, and the complexity of setting up field studies. At the same time, the lack of scientific justification for predicting the parameters of local moisture contours reduces the quality of drip irrigation of plants cultivated on slope lands. In this regard, the purpose of the study was to develop a method for determining the size and construction of moisture contours outlines on slope lands. Object. The object of the study was local moisture contours formed in the soil space during drip irrigation of slightly sloping lands. The subject of research is the shape and geometric dimensions of slope contours of soil moisture. Materials and methods. Experimental studies of humidity contours were conducted on slope areas in the Oktyabrsky district of the Rostov region. The soil cover of land plots presented to the southern heavy-loam small and medium low-humus chernozems, characterized by a content of physical clay level - 58,0 ± 0,4 % of mass of dry soil (% of SMEs); the lowest moisture capacity - 27,0 ± 0,5% of SMEs with a density of meter soil layer 1.3 ± 0.02 t/m3. The steepness of the slopes of the experimental sections was 0, 3, 6, 7 and 9 °. The development of a graph-analytical method for determining the size and construction of moisture contours outlines formed on slope lands was carried out by analyzing and generalizing the experimental material. Results and conclusions. Analysis of the experimental material allows us to note that the distance of the boundary of the moisture contour in the direction perpendicular to the slope of the earth's surface corresponds to those characteristic of contours, which formed on horizontal flat lands, and their values up and down the slope differ significantly from them. The identified functional relationships were described by empirical dependencies, and the generalization of information on the outlines of slope contours allowed us to propose a calculated scheme of the humidity contour. On the basis of the obtained results was proposed graphical-analytical method of determining the shape of the profiles of the local contours of moisture formed on sloping landscapes. A graphical comparison of the experimental contour of soil moisture with the calculated one showed a qualitative and quantitative similarity of their forms. The calculated depth of the moisture contour bounded by the isoplet was 0.72, with an experimental value of 0.75 m. At the same time, the deviation of the calculated value from the experimental depth was 4.2 %. The calculated and experimental values of the average diameter of the humidity contour were 0.78 and 0.83 m, respectively. The deviation between them was 6.4 %. These circumstances indicate the practical applicability of the proposed method for the conditions considered.