The high-yielding lambrusco (Vitis vinifera l.) grapevine district can benefit from precision viticulture

The best Lambrusco wines are often obtained by blending a representative of the Lambrusco family (i.e., Lambrusco Salamino) with a smaller fraction of Ancellotta, a teinturier variety possessing an extraordinary quality of accumulating color. Because of the economic importance of the Lambrusco business and the rising interest in precision viticulture, a two-year trial was carried out in seven vineyard plots growing both the named varieties. A RapidEye satellite image taken on 9 Aug 2018 led to vigor maps based on unfiltered normalized difference vegetation index (NDVI). In both years, ground truthing was performed on the test vines chosen within each vigor area for soil features, vegetative growth, yield, grape, and final wine composition. For data pooled over sites and years, Ancellotta showed a very clear response to NDVI-based vigor mapping, as low vigor areas always achieved improved ripening in terms of higher total soluble solids (+1.24 Brix), color and phenols (+0.36 mg/kg and +0.44 mg/kg, respectively), and lower malate (-1.79 g/L) versus high vigor. Such a behavior was shown even in those cases where NDVI of different vigor levels and pruning weight were not closely correlated and, most notably, low vigor matched with a slightly higher yield as compared to high vigor plots. Overall, the high-yielding Lambrusco Salamino was less responsive in terms of vine performance and grape composition versus intravineyard variability. This study highlights that in Ancellotta, adjusting the vine balance toward ostensible lower vigor (i.e., pruning weight ≤1 kg/m) would result in a superior choice in terms of improved ripening and wine profiles would not be detrimentally affected by the yield level which, in fact, increased in some cases.