3D movement of water in soil at drip irrigation system and mathematical description of the wetting pattern by a new method
Project no. 975 · Status: Kapanmış · 2016
Summary
Analytical description of the wetting pattern in drip irrigation systems is very important from the points of view of the correct projecting of the system, optimum programming of irrigation and sustainable use of deficit resources. Spatio-temporal variations of the components of the wetting pattern allow determination of the relationships between the relative rates of change of the components. Thus, the entire wetting pattern can be described as a function of time. This process allows description of the wetting pattern which occurs at any elapsed time of t0 from the beginning of irrigation. The aim of this investigation was to determine the relationships between the relative rates of change of the components of the wetting pattern, and to describe this pattern analytically in a drip irrigation system. In this process, an experiment was designed to carry out reliable consecutive measurements of the components of the wetting pattern. Also, real-time camera records were taken during this period of time. The wetting diameter on the soil surface, the maximum wetting depth and the maximum wetting width in the soil profile are the main components of the cross-sectional area of the wetting pattern and the model. The sizes of the variables were measured at each five-minute time point. The relationships between these variables were then described as a function of time. In this process, some physical and chemical properties, important for irrigation, were determined for the soil sample on which irrigation applications were performed. Apart from this, the infiltration test was carried out by the double ring infiltrometer technique in the field where the experiment was conducted. The model devised contains directly the components of the wetting pattern. In the next stage, the data from the measurements of the experiment and the results of the models were compared. In this way, the validity of the models devised was verified. The results indicated that these models could describe the cross-sectional area of the wetting pattern and the relationships between the relative rates of change of the components of the wetting pattern in drip irrigation system. Key words: Drip irrigation system, wetting pattern, mathematical modelling.