Microclimatic differences in fruit zone of vineyards on different elevations of ‘nagy-eged hill’ in eger wine region, Hungary

The Bull’s Blood of Eger (‘Egri Bikavér’) is one of the most reputed red wines in Hungary and abroad, produced in the Northeastern part of the country. It is known as a ruby blended, full bodied red wine with fruity and aged character. Vitis vinifera L. Kékfrankos (Blaufränkisch) is the base component of the ‘Egri Bikavér’, beside it is the most abundant red grape cultivar of the region and of Hungary. It is grown in many vineyards along the wine region resulting in different wine quality and style depending on slope, elevation, aspect, soil and microclimatic conditions.

Several attempts using GIS technics have been made recently to characterize the most important growing sites in the wine region concerning topographical, soil and climatic conditions. Data of automatic meteorological weather stations located in the vineyards, E-OBS gridded database and the PRECIS regional climate model was also used to better understand the suitability of the vineyards for Kékfrankos quality wine production.

In the present study, we described with a fine scale measurement the fruit zone microclimate (temperature, relative humidity) in three vineyards differing in their elevation on the emblematic ‘Nagy-Eged hill with EasyLog EL USB-2+ temperature and humidity sensors (Lascar Electronics, UK). The elevation of Nagy-Eged hill lower part [NEL] is 294 m, Nagy-Eged hill middle [NEM] is 332 m and Nagy-Eged hill top [NET] is 482 m above sea level. Measurements were taken in 2015 July-October. Mathematical calculation of multiple comparison, i.e. Marascuillo’s procedure was used to distinguish microclimatic differences among different elevations. Day and night time data were separately analyzed.

Concerning the temperature data of Nagy-Eged Hill, we may suppose that the effect of a thermal belt was the principal factor influencing fruit zone temperature, since the warmest area (especially at night) was the middle part of the hill, although the upper part is far steeper, therefore it could receive more solar radiant heat than the others. Soil is richer in gravels, stones on the top of the hill and in the middle part, but the re-radiation heating effect did not exceed that of thermal belt.
Due to the moving of cooler air masses towards the lower part of a valley and the lower wind speed, the air surrounding the vines gets more humid in most part of the growing season. The advantage of dryer air conditions in the middle and top positions of the hill may be benefited by using environmental friendly cultivation technology with less pesticides.
Climate change is a challenge at the Nagy-Eged Hill not only for temperature increase and water shortage, but also for heavy, irregular precipitation that results in serious erosion problem.