Evaluating environmental factors, geographic scale and methods for viticultural zoning in the high-altitude region of Santa Catarina, Brazil

Abstract

Viticultural zoning involves dividing territories into zones such that the influence of environmental factors on grapevine is homogeneous. Accomplishing this depends on the prevailing environmental factors, including climate, physiography and soil and their influence in distinct spatial scale, i.e., from macro to meso and microscale. Previous research has highlighted the environmental potential for producing quality wines in the high-altitude region of Santa Catarina State, Brazil. However, to further determine if this region is a unique and homogeneous zone for viticulture, two viticulture zoning approaches were adopted to characterize the spatial distribution of environmental factors, to identify the main factors representing environmental heterogeneity at both macro and mesoscale and to identify homogeneous sub-zones. The adoption of the Multicriteria Climatic Classification System (MCCS) and the Multivariate Clustering Approach (MCA) allowed a comparison using both zoning methods. The zoning outcomes from both methods indicated that the high-altitude region is environmentally heterogeneous. The high-altitude region is climatically differentiated by temperature and rainfall variation and topographically differentiated by altitude (ALT) variation and topographic position index (TPI) diversity. MCA allowed for the integration of climatic and topographic factors. The use of climatic parameters resulted in the best zoning at macroscale, while the topographic parameters were indicated for mesoscale zoning. MCCS helped to identify five climatic sub-zones. According to Heliothermal Index (HI), the high-altitude zone can vary from temperate warm (>2100 ≤ 2400) to very warm (>3000). The Cool Night Index (CI) varied from very cool nights (≤12) to temperate nights (>14 ≤ 18). The Dryness Index (DI) indicates that the high-altitude is a humid region (>150). This study demonstrated that the MCCS is indicated for viticultural zoning at macroscale, once it considers only climatic parameters. The MCA is more flexible because permits the use of other environmental parameters and helps to quantify the influence of each parameter in the environmental heterogeneity. We also concluded that the high-altitude region is not homogeneous, so it should not be considered as a unique wine-growing region.