Within vineyard variability as affecting yield parameters and wine quality: results of three years of investigation in Friuli Colli Orientali D.O.C. area

Abstract

The vineyards in the D.O.C. area Friuli Colli Orientali are planted mainly in hills with different expositions and high soil composition and texture variability. Significant land settlements normally are required, resulting in areas with different soil fertility. Winegrowers normally recognise the variability within their vineyards, but the areas with low and high vigour can change due to annual arrangements of soil fertility and plant growth. Several affordable indices are available, among them NDVI is largely recognised as a useful tool to measure differences in vine vigour. This method was applied in the “La Viarte” vinery, to distinguish low/high vigour areas within each vineyard. Plant production and grape/wine quality was then examined at the light of this mapping. During four years (2009-2012) several soil parameters (texture, moisture, organic matter, etc.), NDVI, yield and grape quality parameters were collected in more than 100 sampling points. From 2010 on, four varieties were chosen – Sauvignon, Friulano, Pignolo and Schioppettino – and based on geostatistical analysis of NDVI, for each vineyard low/high vigour areas were mapped. Some important differences were found between low and high vigour for cluster weight (Pignolo and Schioppettino), soluble solids (Friulano), titratable acidity (Friulano and Pignolo) and phenolic composition (Schioppettino). Grapes from low/high vigour area were vinificated separately and the obtained wines were evaluated by an expert panel. Differences between high and low vigour wines were showed, and the season factor was recognised to play an important role.