Measurement and Simulation of Soil Water Flow and Root Water Uptake in Alternate Furrow Irrigation

Since the direct surveillance and data collection on the farm costly and not applicable in all farms, therefore the use of mathematical models necessary. The aim of this study was to investigate soil water flow and root water uptake in every furrow irrigation (EFI), Alternate furrow irrigation (AFI) and fixedfurrow irrigation (FFI) and also calibration and verification of HYDRUS-2D model In order to assess its applicability in the above methods. Field data was collected at growing season corn crop in these methods. To better understand the behavior of the model results were evaluated in two scenarios. In the first scenario model using data from EFI and in the second scenario for each irrigation methods independently calibrated (33% data) and validated (67% data). Estimating the parameters was performed based on soil properties from the database Rosetta and it used in HYDRUS-2D inverse solution for optimize. The Results were compared by indices R2, nRMSE, EF and CRM with each other. The measurement results shows that due to the halving of the amount of irrigation water in the AFI root water uptake was not significantly different with EFI, and The maximum uptake was observed at a depth of 30 cm. Range of R2 value was observed from 0.72 to 0.89 and nRMSE between 0.046 and 0.078. According to calculated nRMSE values, performance of the simulation model, was ranked as excellent for simulation. The results showed that the model was calibrated by initial data separately for each irrigation method increases the accuracy of the model.