Wetting Pattern Dimensions Determination in Drip Irrigation by Coupling the HYDRUS-2D Software and Backingham π Theorem in Texturally Different Soils

For design and accurate management of drip irrigation systems, it is necessary to have sufficient information regarding the dimensions of wetting front (diameter and depth of the soil wetted by drippers) for various soil textures. Such important parameters as soil hydraulic functions, drip discharge and irrigation time influence the dimensions of created wetting front. In this study, new semi-empirical models for determination of depth and maximum diameter of soil wetting front under point source in several soil textures were developed. For this purpose, HYDRUS-2D software was run for an application discharge (3 L/hr) in several soil textures. Using Backingham π theorem and obtained values from software, including depth and maximum diameter of soil wetting front, the equations which estimate the wetting front dimensions were presented for several soil textures. Soil saturated hydraulic conductivity, irrigation time and dripper discharge were the parameters of developed equations. Statistic indices results for all equations (min Correlation Coefficient about 0. 968, max Root Mean Square Error about 2. 120 and max Mean Absolute Error about 1. 376) firm the ability of presented equations in calculation of wetting pattern dimension in different soil structures. On the basis of obtained results, presented equations can be used properly for designing and optimal management of drip irrigation system which is located in any soil textures.