Prediction of wetting patterns under surface drip irrigation using numerical and empirical models

Drip irrigation benefits enhanced the worldwide use of this irrigation system. drip irrigation reduces significantly the wetted soil surface that lead to reduction of evaporative losses. claimed that wetting pattern is a major parameter in optimizing lateral placement and emitter spacing as well as in selecting emitter’s discharge. In other word, to achieve proper drip irrigation design, dimensions of the wetted zone (depth and width) should be accurately determined. Therefore, present study was conducted under clay loam soil to investigate the accuracy of numerical (HYDRUS-2D) and empirical (multivariate nonlinear regression) models in estimating wetting pattern for surface drip irrigation. The predicted values of soil moisture, wetted depth and width were compared with those obtained from laboratory experiments. Experimentations included determination of soil moisture, depths and widths of wetted zone after 1, 2, 3, 4, 5, and 6 hour of water application with three different discharge rates (2, 4 and 8 L/h). Statistical parameters revealed that there was no significant difference between models results and observed values. So that The normalized root mean squared error (NRMSE) varied from 5.8 to 8.2% and 7 to 7.7% for numerical and empirical models, respectively. The results also showed that The proposed empirical model predicts the wetting pattern with acceptable accuracy.