CONICET | Buscador de Institutos y Recursos Humanos

This study advances the understanding and impacts of dry episodes on wheat, corn, and soybean yields over Argentina?s core crop region. The production of these major crops is intense and is the main contribution to the country?s gross domestic product. Our analysis focuses on the droughts? properties, including their magnitude, frequency at different timescales, duration, and severity. We analyzed 40 years of precipitation and soil moisture anomalies and their corresponding nonparametric standardized indices at timescales of 1, 3, and 6 months. The climate variables werecomplemented with 40 years of the crops? yield data. The percentage of drought occurrence in northeastern Argentina ranges between 12% and 18 %, with the larger values located towards the core crop region?s eastern?northeastern sector. An analysis of drought duration suggests that mostcases tend to occur for periods shorter than 3 months, while a few can extend up to 1 year, and even fewer can last longer. More importantly, regardless of the duration, droughts havelarger impacts during the crops? critical growth period. Corn and soybean have their critical growth periods during summer and are more sensitive to precipitation and soil moisture deficits than wheat, which has its critical growth period during spring. Quantification of the relation between thedroughts? indicators during the crops? critical periods and detrended annual crop yields was performed. Large drought severity values during the crop-sensitive months result in significant crop yield losses. Results suggest that shorterscale indicators during sensitive periods are more appropriate for predicting crop yield losses than the longer-scale indicators. This new approach can be helpful for regional decisionmaking systems that support planning by water managers and agricultural stakeholders.

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