Ground-truthing of remotely sensed within-field variability in a cv. Barbera plot for improving vineyard management

Background and Aims: Precision viticulture encompasses a series of techniques from remote to proximal sensing for describing and exploiting within-vineyard variability. Our aim was to assess how vigour mapping associated with detailed ground-truthing can provide guidelines for more sustainable vineyard management. Methods and Results: A satellite image taken with a 5 m-pixel resolution on a mature, small-sized (0.6 ha) cv. Barbera vineyard at full canopy made it possible to build a vigour map on the assessment of normalised difference vegetation index (NDVI) distinguishing low-vigour (LV), medium-vigour (MV) and high-vigour (HV) areas of equal surface. Detailed single-vine records for vegetative growth (shoot length, leaf area and pruning mass), yield components (bud fruitfulness, yield per vine and bunch and berry mass) and grape composition were recorded within each vigour class at harvest; leaf nutritional status and ripening curves were monitored for the same classes. While NDVI showed a close correlation to several vegetative, yield and grape composition parameters, LV vines exhibited excellent performance for remunerative yield (3.2 kg/vine, or a potential yield of 13.3 t/ha) and full ripening with maintenance of adequate TA. Both MV and HV showed excessive vigour and cropping leading towards incomplete ripening. Conclusions: The combination of NDVI mapping and detailed ground-truthing allows the identification of the vigour level for the greatest vineyard efficiency and the definition of an appropriate strategy either to exploit current variability through selective harvesting or to correct variability through variable rate application of nitrogen. Significance of the Study: The NDVI mapping via low-resolution satellite images associated with ground-truthing appears to be a straightforward protocol to increase sustainable vineyard management.