Mapping vineyard vigor using airborne remote sensing: relations with yield, berry composition and sanitary status under humid climate conditions

Abstract

The aim of this study was to assess the spatial variability of plant vigor in a vineyard in a humid climate. Normalised Difference Vegetation Index (NDVI) was used for relating the vigor level to grapevine performance and, as a new area, with the anthocyanin and organic acid compositions of the berries. The study was performed in a rain-fed vineyard with the Tannat cultivar, vertically trellised, during three consecutive vintages (2015–2017). NDVI was estimated from high-resolution images acquired using airborne sensors, which allowed differentiation of three vigor levels within the vineyard: high, medium and low. Three plots per vigor level were installed for performing samplings and field measurements. High vigor zones were associated with less water-stressed vines, higher yields, incidence of bunch rot, larger berries, total acidities and total anthocyanins concentrations. Low vigor zones corresponded to higher pH, soluble solids and phenolic contents in the berries. Medium vigor zones were associated with higher leaf surface, pruning weights, cluster average weights and greater extractable anthocyanins concentrations. The effect of weather conditions of each growing season on grapevine water status was a major factor influencing the analysed variables. NDVI values allowed for delineating areas with homogeneous vigor within the vineyard, which corresponded with different plant performance, showing the usefulness of this tool for site-specific management under the studied conditions.