Simulation of soil water profile in surface and subsurface drip irrigation systems by HYDRUS-2D

Drip irrigation system is one of the most effective strategies to increase productivity and optimal use of available water resources. In the subsurface irrigation distribution water in the soil and decreasing evaporation and water use. Realizing the full potential of drip irrigation technology requires optimizing the available parameters, such as the frequency, rate, and duration of water application. Numerical simulation is a fast and inexpensive approach to studying optimal management practices. Unfortunately, little work has been done to investigate the accuracy of numerical simulations. In this context, numerical models, fast and cheap, to study the operation of irrigation systems and optimizing their management parameters are considered. In the design of subsurface drip irrigation systems, the dimensions of the wetted onion determine the installation depth and set of system. Several models have been developed to simulation soil moisture patterns and the wetting front using hydraulic parameters, discharge and application time.The purpose of this study was to measure soil moisture profiles of surface and subsurface drip irrigation and compare with simulation results using HYDRUS-2D software. In this study, an experiment to study soil moisture profiles, surface and subsurface drip irrigation treatments was performed in the field of Urmia University. T-Tape pipes with discharge of 4 liters per hour at intervals of one meter was installed and the surface and subsurface measurements were performed. Tubes in subsurface drip irrigation was installed at 0.2 meter deep. Water content was measured by WET sensor in both irrigation systems. Water content measurement in two-dimensional depth and radius were recorded every 10 minutes. HYDRUS-2D software simulation in this study was compared with the measured results. The results of the simulation of soil moisture profiles using HYDRUS-2D software was in good agreement with the observed data (RMSE 0.01 till 0.14). Based on results, differences between the measured and simulated data (R2) in surface and subsurface trickle irrigation for 24 hours operation were respectively 0.811 and 0.906. By using three estimation ROSETTA model, hydraulic parameters was evaluated. Based on the obtained error values observed error rate in the two models, Full ROSETTA and ROSETTA Lite negligible and only in some depths Full ROSETTA model error is less than ROSETTA Lite model. In general can be said on the basis of data Full ROSETTA good agreement with the results of the measurement. The results support the use of HYDRUS-2D as a tool for investigation and designing drip irrigation management practices.