Produkcyjność użytków zielonych w Wielkopolsce w aspekcie zmian warunków pogodowych w ostatnim 30-leciu

In this paper the analysis of the effects of climatic changes on the productivity of permanent grasslands in Wielkopolska province in the last 30 years was performed. The weather data was obtained from the Institute of Meteorology and Water Management, and grassland productivity data, that referred to the yield of meadow hay, was sourced from the publications by the Central Statistical Office. Climatic trends in 1985–2014 were determined using the Standardized Precipitation Evapotranspiration Index (SPEI). Linear regression was used for the analysis of the effect of climatic trends on grassland productivity in Wielkopolska. Statistically significant rise of mean yearly air temperature and mean reference evapotranspiration was evidenced for the whole area of Wielkopolska except for its northern part. The significant SPEI trends indicate that soil moisture conditions in January, February and May were improving, whereas in April, November and December were deteriorating. No significant effect of the SPEI trends on grassland productivity in Wielkopolska was found.