Spatial variability of meteorological conditions at different scales in viticulture

The study of meteorological variables can be an essential tool for the characterization of best vintages as these are widely recognized in the literature as a key factor in the definition of grape quality. Meteorological variability expressed both at vineyard scale (mesoclimate) and at single plant level (microclimate) plays an important role during the grape ripening process. The aim of this work was to compare temperature, humidity and solar radiation at different spatial scales to test some factors of their variability in vineyards. The measurements were assessed for two seasons (2011, 2012) in two vineyards of the Veneto region (North-East Italy), planted with Pinot gris and Cabernet Sauvignon and differently pruned. Four sources of spatial variation were examined, from mesoscale to micro-scale: vineyard scale (mesoclimate), field scale (topoclimate), treatment scale (microclimate) and vine scale (microclimate). A comprehensive investigation was conducted, building a factorial design able to evidence the role played by any factor influencing the physical environment in the vineyard, such as the surrounding climate effect, canopy management and relative position inside the vineyard. Several statistical approaches were used to identify factors driven by that spatial variability, including factorial ANOVA and Kruskall multicomparison. The results showed that the impact of the sources of variation on solar radiation and relative humidity is predominantly determined by differences between internal and external monitoring systems (factor LOC) and by the pruning method (factor TREAT). This paper presents novel results about the definition of spatial variability in viticulture at different scales. These results may provide support for the composition of crop production and disease model simulations where data are usually taken from an agrometeorological station not representative of actual field conditions.