Reactions of grape varieties to climate changes in North East Slovenia

Abstract

This work examined the trend of changes in temperature from 1950 to 2009 recorded by the Maribor meteorological station, and from 1980 to 2009 the dynamics of grape ripening of early-, medium late-, and late-ripening vine varieties in the Slovenian Styria wine-growing region in North East Slovenia. Based on the data associated with the content of soluble solids, total acidity, and the recommended date of harvest in a particular year, the trends towards shortening of the grapevine growing period were calculated. In general, temperature changes were more significant since 1980 than between 1950 and 1979. The mean annual and seasonal temperature significantly increased, i.e. 0.06°C per year. The growing season was shortened in all studied varieties from 15 to 27 days. Trends showed significantly decreasing content of total acidity, which can be considered explicitly as a consequence of higher temperatures during the growth period and ripening of grape berries. Grapes now ripen at temperatures which are approximately by 2°C higher than 30 years ago. Regarding the total acidity content of the late-ripening varieties, the influence of higher temperatures is positive. Minor changes were found in precipitations rates.