The purpose of the research is to develop a methodology for determining geometric parameters and a method of graphoanalytical design of moisture contour of drip humidfication based on it. The target of research is the moisture contours formed in soil space during drip irrigation. The subject of research is the position of the boundary line (moisture isopleth), which delineates the moistening zone during drip irrigation – the moisture contour. Considering that by design and operation of drip irrigation systems, the drip moistening zone depth is the preset parameter, the working hypothesis on viability of determining the geometric parameters necessary for contours configurations design in relation to their depth has arisen. In the course of research the experimental dependences allowing to determine the values of the subsurface and maximum diameters of moisture contour at a given (certain) depth of drip irrigation moistening of soil profile, as well as the depth of the moisture contour maximum diameter were obtained by analytical processing of the experimental values of the geometric parameters of a number of moisture contours formed in soils with different soil characteristics. When determining the geometric parameters of drip irrigation contours, such soil indices as the content of clay particles in soil, the minimum moisture-holding capacity and the average rate of pressure water absorption into soil for the first hour of irrigation are taken into account. As a result of the research, a method of graphoanalytical design of moisture contours at drip irrigation, which involves the design of a limiting (contouring) soil moisture contour by the values of their geometric parameters obtained according to the proposed dependencies has been developed.
Key words: drip irrigation, moisture contour, contour geometric parameters, soil parameters, contour outline, contouring isopleth.
