ENSO impacts on maize production: a case study in Argentina

El Niño Southern Oscillation (ENSO) significantly influences crop production by affecting crop yield, failure, or land allocation. However, current studies on ENSO impacts on field crops lack the finer resolution needed to implement effective mitigating or boosting strategies. This study presents a comprehensive methodology for conducting finer resolutions assessments of ENSO impacts on maize, exemplified by a case study in the Argentinean Pampas Region. Maize yield, sown, and harvested area (1984–2023) for 122 departments were analyzed using a Generalized Additive Model (GAM) coupled with bootstrapping (n = 1000) resampling to obtain confidence intervals. Two GAMs were developed, analyzing time trends, and time trends and ENSO fixed effects together. ENSO impacts on maize production were computed from yield differences and analyzed probabilistically. ENSO showed distinctive positive effects on yield in El Niño and negative in La Niña, with effects on the size of lost area dependent on the department considered, and with only small to negligible effects on sown area in the year following a given ENSO event. 81% of the departments were included in an ENSO-yield-responsive cluster, comprising key production areas. Impacts on maize regional production could result in deviations of +6 million tons (Mt) for El Niño and -5.5 Mt for La Niña, with the responsive cluster accounting for the majority of its effects. This study delineated a framework to assess the effects of ENSO on a crop relevant to food security like maize, providing the tools to conduct future studies in other areas and crops, placing the focus on the finer-resolution scale of analysis and on key variables that determine crop production.