Agronomic classification between vineyards ('Verdejo') using NDVI and Sentinel-2 and evaluation of their wines

Abstract

A classification between three vineyards belonging to the Appellation of Origin Rueda (Castilla y Leon, Spain) has been established in veraison to determine the productive capacities of each vineyard and to study their impact on the grape quality. Several open-access multispectral images obtained from the SENTINEL-2A satellite in the year 2016 were used to calculate the NDVI (Normalized Difference Vegetation Index), which provides information about the vigour of the vineyards. Eleven cloud-free images were assessed and based on the NDVI, three vigour levels were established: high vigour (0.356-0.458), medium vigour (0.285-0.355) and low vigour (0.166-0.284). A level of vigour was assigned to each vineyard according to the NDVI mean values of its pixels. Significant differences were found in the pruning wood weight and yield: high, medium and low vigour values were 2438, 1895 and 1487 kg·ha-1 and 15984, 12990 and 10576 kg·ha-1, respectively. The highest values of total acidity (6.04 g·L-1) and tartaric acid (9.05 g·L-1) have been obtained in low vigour, as well as the lowest values of pH (3.26), malic acid (0.42 g·L-1) and potassium (1640 ppm). Finally, one wine per vigour was produced and a tasting was carried out to check if the differences between the vineyards were perceptible. According to the obtained results, the NDVI is a good indicator to classify vineyards, finding notable differences between the experimental treatments studied.