Analysis of viticultural potential and delineation of homogeneous viticultural zones in a temperate climate region of Romania

摘要

Aims : To characterize the viticultural potential and delineate homogeneous viticultural zones in the Hu?i wine growing region (Romania) in order to provide necessary information for viticultural zoning.Methods and results: The methodology is based on a Geographic Information System (GIS) analysis of 15 ecological parameters, representative of the topography, climate and soils in temperate continental climate vineyards. Three homogeneous viticultural zones were identified : one suitable for quality white wines and red table wines ; one suitable for quality white wines ; and one suitable for white table wines, sparkling wines and wines for distillates.Conclusion: In order to characterize the viticultural potential, it is necessary to assess the suitability of all ecological factors that influence the quality of the grapes. Omitting one ecological factor may lead to erroneous results in suitability assessment. Climate suitability determines altitudinal differentiation of the viticultural potential, while topographical and pedological suitability determines a horizontal differentiation.Significance and impact of the study: This study provides the necessary information for viticultural zoning in the Hu?i wine growing region in Romania. The methodology allows to evaluate viticultural potential and to delineate homogeneous viticultural zones in wine growing regions with a temperate continental climate. IntroductionUnlike other crops, whose efficiency is mainly determined by yield, the main criterion in viticulture, and particularly in wine grape varieties growing, is the quality of the crop. Another evaluation criterion is the presence of some features that give uniqueness to wines and allow recognition of their geographical origin. All the elements that define the value of the crop for wine varieties are subject to “vineyard viticultural potential”. The term has a broader meaning defining both the suitability for vine growth and for high quality crops. Generally, an area is considered to have viticultural potential if it enables the growth of quality grapes for at least one type of viticultural production (e.g., table grapes or table wines, quality wines, sparkling wines, late harvest wines, etc.) (Irimia, 2012). When it comes to wine varieties, an area is considered to be suitable for producing quality wines if it ensures full ripening of grapes, with a consistent quality from year to year (Seguin, 1986).Viticultural potential is determined by the complex interaction of all the ecological factors that interact in the vineyard: relief, climate, soil and subsoil. All of these factors determine the quality of the crop through the influence that they have on the composition of the grapes: temperature influences sugar, anthocyanin and malic acid content (Kliewer and Lider, 1970; Buttrose et al., 1971; Coombe, 1987); thermal amplitude between day and night influences anthocyanin and aromatic content (Kliewer and Torres, 1972; Tomana et al., 1979); precipitation can affect grapevine disease incidence/severity and berry maturation (Tregoat et al., 2002); solar radiation influences anthocyanin, sugar and malic acid content (Buttrose, 1970; Kliewer, 1977; Crippen and Morrison, 1986; Dokoozlian and Kliewer, 1996); soil nitrogen content influences not only vigour, berry weight and sugar, anthocyanin and tannin content (Choné et al., 2001; Hilbert et al., 2003) but also the aromatic potential for white wine varieties (Peyrot des Gachons et al., 2005); calcareous soil components influence phenolic compound content (Seguin, 1983); and clay favours anthocyanin accumulation (van Leeuwen et al., 2004) and volatile compounds (Coelho et al., 2009). Moreover, we can add relief, which, through its influence on climate (Gladstones, 1992; Dumas et al., 1997), becomes a major factor in determining the viticultural potential.Local variation of natural factors generating viticultural potential produces prominent vineyard-scale variability, which is reflected in the quality of grapes and wines. This is why vineyards are composed of numerous microareas with distinctive ecological profiles, which, in turn, produce distinctive wines with identifiable origins. The name given to these microareas is “natural terroir units” (Morlat, 1989). Because the term “terroir” involves “social and historical experiences and technical choices” (Vaudour, 2003), a more general term can be “homogeneous viticultural zones”. Their analysis and delineation represent stages of viticultural zoning, where the main purpose is to delimit “designation of origin” areas in order to protect them (Vaudour and Shaw, 2005). This can also be useful for setting the best suited wine grape varieties assortments, selecting new vineyard sites and optimizing technical practices in vineyards.The methodologies used to characterize and delimit the homogeneous viticultural zones have been documented extensively in previous works (Asselin et al., 2001; Deloire et al., 2005; Vaudour and