NUMERICAL SIMULATIONS AND VALIDATION OF WATER FLOW AND HEAT TRANSPORT IN A SUBSURFACE DRIP IRRIGATION SYSTEM USING HYDRUS‐2D

Abstract

ABSTRACTSubsurface drip irrigation (SDI) systems are often recommended to overcome water scarcity in arid and semi‐arid regions. To properly manage SDI systems, precise prediction of distribution and transport of soil water content and temperature (important soil physical factors for plant growth) around the emitters must be known. In this paper, the computer software package HYDRUS‐2D was used to evaluate the distribution and transport of soil water content and temperature around an emitter in a silt loam soil. The model was validated by comparison with measured data from field experiments involving SDI with emitters installed at 25‐cm soil depths. Model performance in simulating soil moisture and temperature was evaluated by comparing measured and predicted values using three parameters: model efficiency (ME), root mean square deviation (RMSE) and mean bias error (MBE). Values of ME, RMSE and MBE between measured and simulated soil moisture ranged from 0.71 to 0.84, 0.013 to 0.019 and 0.004 to 0.007 and between measured and simulated soil temperature ranged from 0.81 to 0.86, 0.97 to 1.33 and 0.13 to 0.28, respectively. Based on these values, it can be concluded that there was good correspondence between simulations and observations and the HYDRUS‐2D can be commendably used to describe soil water and heat transport properties involving SDI and also for investigating and designing drip irrigation management practices. Copyright © 2013 John Wiley & Sons, Ltd.