Impacto económico del riego en los cultivos de maíz y soja en el litoral Uruguayo

Cereal crop production in Uruguay has experienced significant growth since the beginning of the century, with summer crops showing the greatest expansion. Most of these crops are grown under rainfed conditions, despite the fact that rainfall during the summer months is often insufficient. Although several studies have demonstrated that irrigation increases crop yields, research focusing on its economic impact remains limited. Therefore, the objective of this study was to evaluate the economic impact of irrigation on maize and soybean production in the western region of Uruguay during the 2019/2020 to 2023/2024 growing seasons, determining its effect on economic returns compared with rainfed production. The specific objectives were: (i) to quantify the economic margins of irrigated and rainfed maize and soybean production during the 2019/2020 to 2023/2024 growing seasons in western Uruguay; (ii) to compare production costs and crop yields obtained under both production systems throughout the study period; and (iii) to identify the technical and management factors influencing the economic performance of irrigated and rainfed production. The study was based on quantitative data obtained from two farm databases (FUCREA and RUU) covering the western region of the country. Using these data, production costs and yields were calculated for irrigated and rainfed maize and soybean fields over the five growing seasons. Gross revenue (GR), direct costs (DC), and gross margin (GM) were subsequently estimated. Secondary sources were used to obtain input and output prices. To determine the existence of statistically significant intra-annual differences among the variables analyzed, Welch's t-test was applied. The results showed significant differences in gross margins between rainfed and irrigated systems in four of the five growing seasons for first-crop maize and first-crop soybean, whereas for second-crop soybean these differences were observed in two of the five growing seasons. Overall, supplemental irrigation improved the partial economic performance of the crops analyzed. However, the magnitude of its benefits depended on the crop considered and the climatic conditions of each growing season, highlighting the advantages of irrigation under water-deficit conditions.