Abstract:

The degree of Agricultural Engineering at the Universitat Politècnica de València includes several subjects aiming at providing the theoretical and practical fundamentals of irrigation and drainage engineering to students, so that they might be able to perform the design of irrigation installations in their professional future as engineers.

Matlab is a high-level technical computing language and interactive environment for algorithm development, data visualization, data analysis and numerical computing. It allows a huge variety of computational possibilities and has become a very valued tool for all kind of engineers. Therefore, all engineering degrees at the Universitat Politècnica de València include a general training on this software in subjects of Mathematics. Nevertheless, it is not possible to offer a specific training on the application of this software for the specific scenarios in all subjects of a technical degree.

This paper presents a practical session of the subject ‘Irrigation and Drainage’ corresponding to the degree of Agricultural Engineering at the Universitat Politècnica de València. This session focuses on the potential of this mathematical tool for solving problems in this subject in comparison to conventional procedures. Specifically, this session focuses on the calculation of crop water requirements according to two well-known methods for estimating reference evapotranspiration (ETo): the Hargreaves (HG) and the Penman-Monteith (PM) methods. ETo estimation is crucial for irrigation scheduling and the agronomic design of installations. The suggested methodological approach might be extended to other routine-based calculation scenarios in this subject, like the pressure and flow distributions in a micro irrigation subunit when assessing its distribution uniformity.

Therefore, the session shows how to estimate ETo according to the mentioned methods in 10 stations (5 coastal and 5 inland) of the Valencia region using Matlab. First, the students check the reliability of the climatic series considered for the study, excluding possible outliers. Second, a program is implemented to provide daily HG and PM estimations. Third, the HG equation is locally calibrated in each station using PM benchmarks. Finally, the estimations of both models are compared and the calibrated and non-calibrated HG estimates are assessed through k-fold testing in relationship to the local thermal range.

The benefits of this session can be summarized as follows. Students are trained for specific applications in this subject using a robust computational software. Theoretical contents of the subject are visualized more easily. Students learn to extend this methodological procedure to other routine-based computational scenarios that might be encountered in this field and in other ones. They also get in touch with computational tools used in this research area and with the research topics tackled by the staff of this department.

Keywords:

Matlab, crop water requirements, reference evapotranspiration, practical session.