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

Use of Sentinel-2 Satellite for Spatially Variable Rate Fertiliser Management in a Sicilian Vineyard

“…The NDVI temporal evolution for the two surveyed cultivars differs from that found by other scientists. In fact, Vélez et al [18], for the Verdejo cultivar, found a lower peak in July and a higher one in September, after harvest (instead of the highest peak found in June in this study). Moreover, Heemann Junges et al [36] found, on average, a peak when the berries begin to swell in the second half of October (which, for climate conditions, is very similar to June in the boreal hemisphere), for the Chardonnay variety, and a peak when the berries touch each other in the first half of December (which, for climate conditions, is very similar to July-August in the boreal hemisphere), for the Cabernet Sauvignon variety.…”

“…The applications of remote sensing [4] to agriculture include crop type (i.e., plant species) mapping; crop condition assessment; crop yield estimation; mapping of soil parameters and crop operations (e.g., tillage methods); monitoring the compliance of crop operations to EU regulations; and directives, e.g., "Farm to Fork" and European Green Deal [5][6][7][8][9][10]. The images remotely sensed from Unmanned Aerial Vehicles (UAVs) [3,11,12] or Remotely Piloted Aerial Systems (RPASs) [13], aircrafts [3] and satellites [5,[14][15][16][17][18][19] are used as mapping tools in order to classify crops and examine their health and viability, as well as monitor crop operations.…”

“…Finally, the use of UAVs or aircrafts implies an initial investment, as well as having qualified personnel capable of setting up and piloting these devices and performing subsequent processing of the obtained data, while satellite imagery providers provide ready-to-work images and offers the possibility of consulting the images archive A threshold value slightly higher than five was been established: above such a scale size, images taken by satellite may be more convenient rather than those acquired by UAVs. However, these two image sources can be combined to contribute to the decision-making process as well as in vineyard management [18].…”

“…The Sentinel-2 mission comprises a constellation of two polar-orbiting satellites placed in the same sun-synchronous orbit, phased at 180° to each other. It aims to monitor the spatial and temporal variability of land surface conditions [18,[25][26][27][28][29][30][31].…”

“…In fact, NDVI can be applied to evaluate the plant photosynthetic activity and, therefore, its vegetative vigour and soil coverage during growth phases, so that it is measured by optical sensors (e.g., Arvatec OptRx and Trimble GreenSeeker) for planning fertilisation [12,[32][33][34][35][36][37] and irrigation. Therefore, NDVI mapping remains the most affordable way to easily and objectively obtain vineyard spatial information [3], as this index has proved to be a useful tool for monitoring crop yield [18] and table grape quality characteristics [14]. Moreover, NDWI can be applied to evaluate plant water stress and leaf water content during growth phases, so that irrigation can be monitored in near real-time in order to improve agriculture efficiency, especially in areas where meeting the plant need for water is more challenging [38].…”