El Nino — Southern Oscillation Influences on Wheat Crop in Brazil

The El Nino-Southern Oscillation (ENSO) phenomenon influences the climatic behavior in different areas of the world. In Brazil, this phenomenon affects the northern part of the Northeast Region, the eastern Amazon (in the tropical area) and the extra-tropical area of the Southern Region. The climatic variability associated with the ENSO phases, especially rainfall anomalies, may be quantified and this information can be effectively used by crop managers to reduce associated risks or to make better use of forthcoming favorable climatic conditions. The objective of this study was to identify the ENSO phases influencing wheat production in Brazil. The impact of these phases on grain yield was based on a historical series of yield data from 1920 to 1997. For 23 El Nino occurrences analyzed at national level, the deviations in wheat yield were negative in 61% of the cases. For 15 La Nina events, positive influences on wheat yields were observed in 73% of the cases. In the 40 neutral years, 55% of the time yield deviations were positive and 45% of the time were negative. Therefore, the ENSO phenomenon influences wheat yield in Brazil. In general, it causes positive impacts in La Nina years and negative impacts in El Nino years, particularly in the Southern part of the country.