Identifying critical periods with low rainfall that impact wheat yields in Argentina, in order to minimize risks

PENALBA O.C., STAINOH F.A., PÁNTANO V.C.;

Christchurch

Conferencia; 13th Int. Conference on Southern Hermisphere Meteorology and Oceanography; 2022

AMS

Wheat yields are affected by climatic conditions that can limit the available soil moisture in specific stages of the phenological period. In Argentina, more than 80% of wheat is harvested in the Pampas region in rainfed agriculture. In this region, monthly rainfall varies temporal and spatially, showing high probability of water stress.The objectives of this research are: a) to determine periods when low rainfall impact on potential wheat yield; and b) to evaluate the El Niño-Southern Oscillation (ENSO) signal. For this purpose, observed daily rainfall data and wheat yields simulated by the agronomic model DSSAT were used, in 13 stations located in the Pampas region in the period 1961-2017, provided by the Argentine National Weather Service.Initially, sensitive periods in wheat yield associated with two water indices (accumulated rainfall and number of dry days) were determined from Pearson correlations, in different moving windows of 15, 30 and 60 days. Then, the probability of low yields with low accumulated rainfall was calculated. Finally, the signal of ENSO events in these periods of low rainfall associated with low wheat yields were analyzed.The results allow to identify subregions and sensitive periods in which the probability of low yields associated with low rainfall exceeds 60%. Additionally, there is a stronger ENSO signal on the wheat yields to the south of Pampas region.This knowledge provides robust information to reduce their impacts, contributing to the Early Warning System within the framework of the National System for Integrated Risk Generation.