Abstract
Climate, along with soil composition and topography, is one of the dominant biophysical factors controlling growth for practically every type of field crop. In mountain regions, agriculture is under great pressure from multiple factors: small scale socio-economic dynamics, complex topography and an increased exposure to land use and climate change. Given these circumstances, it is crucial to utilize regional evaluation methods that explicitly consider crop suitability in the context of local environmental dynamics and topographic conditions. Farmers require such tailored evaluation to develop sound land-management strategies (i.e. the selection or distribution of grape varieties), while regional authorities require them to support decision-making processes regarding crop-specific national and EU regulations (i.e. planting rights and funding) and landscape planning issues (i.e. landscape protection). In this study, viticultural zoning for the South Tyrolean region (Province of Bolzano, Figure 1) is achieved by combining interpolated temperature datasets (2001-13), different long-term solar radiation time series and a modelled potential radiation map into a spatially explicit modelling approach. There is a particular focus on the relationship between solar radiation and air temperature in complex mountain terrain. Our results indicate that topography can have a strong impact on heat accumulation, with solar radiation explaining large parts of the variance in air temperature. Ultimately, this study identifies suitability limits for viticulture in South Tyrol that vary between 800 and 1100 m above sea level, depending on the topographic properties and the resulting differences in radiation potential, and delineates the possibilities and limitations of viticulture in the South Tyrolean study site.