Spatial characterisation of natural terroir units for viticulture in the Bottelaryberg-Simonsberg-Helderberg winegrowing area

[摘要] ENGLISH ABSTRACT:There is an increasing demand by the consumer for knowledge and understanding of theorigin of each wine produced. This origin is directly linked to the interaction between theenvironment and grapevine, and therefore to the terroir. A terroir can be defined as a complexof natural factors being expressed through the final product and must therefore be studied intwo steps, namely, the identification of relatively homogenous natural terroir units followedby their ecophysiological characterisation.The aim of this study was to characterise the Bottelaryberg-Simonsberg-Helderbergwine growing area according to existing digital information and to identify natural terroirunits. The study area is situated to the southwest of Stellenbosch and covers an area ofapproximately 25 000 ha.Topography is a static feature of the landscape and affects the sunlight interception by a slope,exposure of a site to winds and drainage of soil water and air. It forms an importantcomponent of the terroir concept and has a strong interaction with the environmentalcomponents of climate and soil. The study area is bordered by mountains and bisected by ariver valley resulting in a large variation in aspect and altitude affecting both spatial andtemporal temperature variability.There is no doubt as to the important effect of climate on wine character and quality. Anumber of indices can be used to describe the regional climate. The study area has aMediterranean climate with notable spatial variation of all climatic parameters due to itscomplex topography and proximity to the ocean.The effect of geology on wme character is less clear but appears to act through itscontribution to the physical properties of the soil. In the Bottelaryberg-Simonsberg-Helderberg study area the geology is complex due to the high degree of tectonic movementand mixing of parent material. In situ weathering of rocks is seldom the only source of soilformation.Soil has a number of contributing factors affecting wine character and quality, inter alia, soilcolour, temperature, chemical composition, depth and texture (affecting the water supplyingproperties of the soil). It is the last two that appear to have the most significant effect. Soildepth affects the buffer capacity of the soil to temper climatic extremes and the water supplyhas a well-recorded effect on vine growth and functioning. There is a high degree of soilvariation in the Bottelaryberg-Simonsberg-Helderberg study area that is difficult to representin soil associations. A pattern of soil distribution, however, can be noticed in relation tolandscape variation.Terrain morphological units, altitude and aspect were used as pnmary keys for theidentification of natural terroir units. Broad soil categories and geological information wereincluded at a secondary level. This resulted in 195 units. These natural terroir units will formthe basis for future ecophysiological characterisation in order to determine possible futurecultivar distribution as well as the terroir effect on wine character.

[发布机构] Stellenbosch University