Weighing lysimetric system for the determination of the water balance during irrigation in potted plants

In years, the availability of water for irrigation is one of the main problems in Mediterranean Agriculture. That is why new technologies must be used to achieve proper irrigation management which is the main determinant of the quality and quantity of harvests and involves determining crop water needs. This paper presents a study for the development and implementation of an instrumentation system capable of accurately determining water balance during irrigation periods using a weighing lysimeter for potted crops. The mechanical structure of the lysimeter was designed and validated by our research group in previous works. In the design, the main requirements were high precision and low cost to make it affordable to most farmers. For this reason, the system was implemented using an open source platform and precision instrumentation to ensure accuracy of the measurements. A high-precision flowmeter was used to monitor the supplied irrigation water. The system was also capable of sending data wirelessly to a server in the cloud so they could be later queried from any device with Internet access. Field trials were conducted in order to collect data in both irrigation and non-irrigation periods. The application of filtering techniques was required, so a Savitzky-Golay smoothing algorithm was selected to obtain reliable data of instantaneous evapotranspiration. In the data analyzed, a decrease between 10% and 20% was observed in the hourly evapotranspiration during the irrigation intervals.