In light of the indisputable link between climate and viticultureshort-term and long-term modifications must be adopted to the upcoming climate changes in order to delay ripeness and secure wine quality.
4.1. Short-term measures
4.1.1 Adjustments in vine training and canopy architecture
The first possible measurefor winegrowers should be the modification and adaptation of viniculture techniques. Among them, foliage management techniques will be of particular importance in order to improve the microclimatic conditions within the grapes (to avoid excessive grape exposure) and to regulate the relationship between active leaf area and production to ensure balanced ripening, with appropriate use of annual cultivation operations (pruning, tipping and topping).
Water supply is important for winegrape cultivation. Thus, irrigation is one of the most important practicesfor quality vine production. The aim should be to maintain mild or moderate water deficitlevels for the red varieties while, the target should be a more favorable water status to ensure grape shading and late ripening for the white varieties. The most modern method for achieving the above objectives is irrigation by applying Regulated Deficit Irrigation (RDI).
4.1.3 Soil management
Soil management techniques depend on the circumstances. For example, cover crops hould be the appropriate measure where the aim is to save soil water. On the contrary, plant cover should be adopted on sloping vineyards to avoid erosion.
4.2. Long-term measures
4.2.1 Substitution of early ripening varieties to late ripening varieties
A long-term action would be genotype change. Substitutethe cultivated varieties should aim at choosing varieties that are more resilient to warmer (late ripening) and drier climates. In general, indigenous Greek varieties have greater adaptability to dry-heat environments compared to the international ones.
4.2.2 Substitution of rootstocks
Drought-resistant and salt-resistant rootstocks should be preferred, particularly in the case of arid soils with low water capacity but also in cases where irrigation water is not possible. More specifically, some rootstocks namely, 110R, 1103P and 140Ru are preferred when irrigation is possible because of their highly branched root system. Resistant rootstocks on saline soils proved to be 1103P and 140Ru.
4.2.3 Planting density and vine training
Among the permanent viticultural techniques, planting density and training system can significantly influence vine’s adaptability to the new conditions. Where water supplies of a given region are limited and at the same time irrigation are not possible, denser plantings and low shaping should be chosen to ensure better soil utilization by the roots and to reduce the loss of moisture through evapotranspiration.
4.2.4 Higher altitudes and north-facing slopes
It is internationally accepted that air temperature declines of approximately 0.6oC per 100m. Shifting the optimal temperature range for the varieties of the vines to colder climates (northern to the N. Hemisphere and southern to the S. Hemisphere) will necessitate geographic shifting of the vineyards in order to exploit new areas that are more suitable. In addition to shifting to latitude, the use of new areas could include the transition to slopes (mainly N exposure), mountainous areas (lower average temperatures), coastal (or riparian-labyrinthine) areas (cool and wet sea winds, reduction in daily thermometric range.
In that case, vineyards relocation to higher altitudes, as a long-term measurement may allow growers to achieve ripenesswithin a wider calendar “window”.
4.2.5 Changing wine styles
Changing wine style preferences (i.e. red or sweet wines instead of whites), of a given region,could be a viable solution for wine-growers if future climatic conditionsconsidered unfavourable for the production of a certain type of wine. Under increasing temperatures, the appropriate wine style should follow the order: (a) white winegrape varieties, (b) red winegrape varieties for direct consumption dry wines,(c) red winegrape varieties for aging wines, (d) varieties for sweet wines and (e) table varieties. In general, changing a variety, area or product will be more difficult in winegrowing regions that producing wines of controlled geographical origin, where geographical boundaries, varietal composition and product type are strictly regulated by legislation.
- Fereres, E. andR.G. Evans. 2006. Irrigation of fruit trees and vines: an introduction. Irrig. Sci. 24: 55-57.
- McCarthy, M,G,, B.R. Loveys, P.R. Dry and M. Stoll. 2000. Regulated deficit irrigation and partial rootzone drying as irrigation management techniques for grapevines. Deficit irrigation practices. FAO Water Reports No 22. Rome, Italy, pp 79–87.