The article discusses the results of field study on moisture contours formed during subsurface drip irrigation. This irrigation method for fruit tree plantations comparing with technology of surface drip irrigation has the advantage of dry top soil layer (5–10 cm) which reduces the amount of unproductive physical evaporation from the soil surface. The objective of the research is to develop a method for determining and predicting geometrical parameters of moisture contours based on our own experimental data and data published by another authors. The method is presented as an algorithm for calculating parameters such as height of capillary rise of water above the orifice of subsurface injection moisturizer; depth of gravitational water outflow to soil layers located below the moisturizer orifice; diameter of moisture contour (defined by points of maximum distance of isopleths for the same level of moisture from the moisturizer orifice in horizontal direction). The relationship for irrigation rate of a single injection moisturizer providing the moisture contour of a given depth was proposed. The comparison of calculation results obtained by math relationships and experimental data is presented. We recommend using article materials for design subsurface drip irrigation systems for orchards and vineyards.
Keywords: moisture contour, moisture depth, contour diameter, capillary rise, injector, moisturizer, subsurface drip irrigation, local irrigation.
