Monitoring soil water status for micro-irrigation management versus modelling approach

Simulation models, based on the Richards equation, allow the distribution of water in the soil to be determined taking into account the field conditions. Some models incorporate inverse calibration techniques which permit the parameters of the hydraulic functions to be adjusted so that they can adequately reflect the hydraulic behaviour of the soil. These models can analyse irrigation strategies to optimise the use of water but few studies exist where the results of the models are compared with the results observed in the field. In this study, sensor measurements of the soil water content and the soil water potential were used to adjust the hydraulic conditions of the soil by means of inverse calibration techniques. Once calibrated, the HYDRUS code was used to predict the matric potential at the same point where the sensors were located when used to manage irrigation by micro-sprinklers in an apple orchard. There was agreement between the observed and simulated soil water potentials; thus, it was concluded that the model was useful and fulfilled its proposed objectives.