Influência do evento El Niño oscilação sul no custo da irrigação por aspersão para a cultura do arroz irrigado (Oryza sativa L.) em Uruguaiana/RS

Abstract

The present work aimed to estimate the cost and use of water in sprinkler irrigation for the cultivation of irrigated rice (Oryza sativa L.) and to analyze the influence of the El Niño and La Niña phenomena in order to determine their economic impacts on the irrigation of according to the Emergency date. The work was carried out with the implementation of a thermal sum model using the Excel® platform, and was based on the city of Uruguaiana/RS, the largest producer in the state of Rio Grande do Sul. The period analyzed was from September 15 to 15 from May between 2010 and 2020, totaling 10 agricultural harvests and had data obtained from the INMET and SISDAGRO platforms, where the Maximum and Minimum Temperatures, Precipitation and Evapotranspiration References were obtained. Three sprinkler irrigation depths were stipulated (100, 150 and 200% of the Culture Evapotranspiration, ETC). The need for irrigation was determined based on rainfall, when irrigation above 5, 20 and 30 mm was not accounted for on the same day, on the following and on the two following days, respectively. The cost was estimated based on the average value of kWh/mm over the last 5 years, obtained by consulting a company specialized in the region. By observing the precipitation data, it was found that the presence of the El Niño phenomenon causes an increase in the precipitated volume, as well as a reduction in crop evapotranspiration, and favors the distribution of rainfall during the analyzed period, which reduces the cost and irrigated volume, favoring the use of the system. When the occurrence of La Niña or Neutro, there is a greater use of water and consequently higher irrigation costs.