Irrigação Autonôma Integrada Para Eficientização do Uso Da Água E Energia

Abstract

The efficient use of water and energy are some of the main challenges of irrigated agriculture. On average in Brazil, irrigators spend around 10% of the total production cost on energy, and due to lack of correct management, they waste 20 to 30% of the water applied. There are many technologies available to increase the efficiency of both systems and management, one of which is irrigation automation. If, on the one hand, the automation of irrigation systems is still not widespread among small irrigators, it is quite widespread among those who produce in protected environments. However, correct irrigation management is still little adopted due to the lack of management integrated into the automation system. In large areas, especially irrigated by central pivot, irrigation management programs have been adopted more frequently. However, there is still an excessive expenditure of energy in pumping water, as pumping station engines are normally sized to meet the steepest point of the terrain, leaving the irrigation system constantly operating at maximum power, wasting energy. In this case, the technology that needs to be used is the frequency inverter in the electric motor. However, commercially available options are expensive, which limits access to this technology by irrigators. Thus, the objectives of this thesis were: 1) to develop a low-cost irrigation controller with integrated irrigation management based on information from soil and/or climate sensors, and its field validation in irrigation management for pepper crops in protected environment; 2) build a low-cost motor pump rotation control system, considering the variation in system pressure according to the variation in terrain unevenness, and validate the proposed system, in an area irrigated by a central pivot, evaluating the effects on the blade irrigation, uniformity of water application, and their consequences in millet cultivation. The studies were carried out in the laboratory and in the field at EA-UFG in Goiânia-GO, from 2022 to 2023. In study 1, pepper plants irrigated by the new controller produced 10.48% more flowers and 36.78% more peppers per plant, using 39.70% less water throughout the cultivation cycle, compared to the conventional controller. Thus, the new system is an important alternative for irrigation automation, with the advantage of integrated autonomous management and low cost. In study 2, there was an effective reduction of 8.11% in the engine's electrical energy consumption. The modernization cost was 36.87% lower compared to commercial automation. The fluctuation in the unevenness of the land altered the irrigation depth, but did not interfere with the uniformity of water applied, and consequently no difference was observed in the growth and productivity of millet plants. Therefore, this alternative modernization is a viable technical option for central pivot systems, and its viability increases as the terrain gradient increases.