Streszczenie:

This paper analysed the direction and the degree of significance of changes in selected indicators of climate risk for grain maize in the long-term period of 1985-2014 for the Bydgoszcz region. On the basis of meteorological data originating from the Research Station of the Bydgoszcz University of Science and Technology in Mochełek, the following unfavourable weather factors for maize cultivation were determined: a shortened period of plant active growth, the occurrence of late spring ground frosts, meteorological droughts and agricultural droughts. On the basis of the research conducted, a high temporal variability was found for weather conditions that are unfavourable for maize cultivation, as such conditions occurred with varied frequency, depending on the type of the adverse factor and the assumed criterion for its determination. No significant trends were found regarding the changes in the examined climate risk indicators for production of maize grain over the period between 1985 and 2014, apart from an increase in the number of moderate and strong late spring frosts. The research demonstrated an increase in temporal variability of the length of the plant active growth period and the occurrence of moderate and strong late spring frosts, as well as a clear decrease in temporal variability of maize water supply in 2000-2014 as compared to the previous 15-year period of 1984-1999.