CR 78:135-147 (2019)  -  DOI: https://doi.org/10.3354/cr01563

ABSTRACT: Russia has become the foremost wheat exporting country worldwide. Episodic production breakdowns caused by extreme weather during sensitive stages of crop development are hence of concern not only for the domestic but also for the global wheat market. In this study, we examine heat stress occurrence and availability of rainwater during the flowering period, and investigate their impacts on the winter and spring wheat yields of 3 major production areas of Russia. We also consider the role of atmospheric blocking as a precursor of extreme weather, and assess the correlation between blocking duration and yield. Owing to the later occurrence of flowering in spring wheat and the warmer climate of southern European Russia, we find the probability of heat stress to be higher in spring than in winter wheat, and higher in the south than in the north of the study area. For spring wheat, the negative association between yield and heat stress is stronger than the positive association between yield and total precipitation. The reverse is true for winter wheat. In all regions and for both wheat types, heat stress occurrence and total precipitation amounts correlate significantly with the area-weighted average number of blocked days. We also find a correlation between blocking duration and yield, but results are significant only for spring wheat.

KEY WORDS: Wheat · Atmospheric blocking · Heat stress · Drought · Russia