Associations between grain crop yields in central-eastern Argentina and ElNino-Southern Oscillation

Associations are investigated between yields of major crops in the Argentin e Pampas (central-eastern Argentina) and EI Nino-Southern Oscillation (ENSO ) phase. For maize and sorghum, higher (lower) yield anomalies occur more f requently than expected by chance alone during warm (cold) ENSO events. For both crops, the depression of yields during cold events is, on average, la rger and less variable than yield increases are during warm events. A yield decrease during cold events also is observed in soybean yields, although t he effect of warm events is not statistically significant. There is a margi nally significant tendency for low sunflower yields to occur less frequentl y than expected during cold events. Wheat, the only winter crop considered, did not show an association with ENSO. Precipitation anomalies during Octo ber-February (the period with strongest ENSO signal in the Pampas) are summ arized through principal component analysis. Precipitation anomalies during November-January are significantly correlated with maize, sorghum, and soy bean yield anomalies. In turn, those precipitation anomalies show a distinc t ENSO signal. Late spring-early summer precipitation, then, appears to med iate associations between ENSO phase and yields of maize, sorghum, and soyb ean in the Pampas.