Monitoring the Relationships Between Soil Parameters and Vegetation Vigor in Citrus × Clementine Orchards: Preliminary Results

In precision agriculture (PA), unpiloted aerial vehicles (UAVs) and remote sensing techniques play an important role in data collection in monitoring tree and herbaceous crop conditions. In this abstract, we present the first results of still ongoing research on monitoring the relationships between soil parameters and vegetation vigor in a clementine (Citrus × clementine Yu.Tanaka) citrus orchard. Clementine production in the Calabria region (southern Italy) is labelled with the European Protected Geographical Indication (PGI) marked ‘Clementine di Calabria’. We tested the proposed methodology in an orchard in Corigliano-Rossano Province (Calabria, Italy). Soil parameters were surveyed in 30 surveying points distributed, following a geometrical approach, in 10 lines (3 points for each line) spaced 100 m apart. Multispectral images were acquired with a 6-sensor camera equipped on board a UAV. The identification and extraction of trees’ canopies from processed UAV images were obtained using the geographic object-based image analysis approach (GEOBIA) to generate vigor maps of the citrus orchard. Multiresolution and multi-threshold segmentations were implemented using spectral and topographic band layers, followed by a classification step based on a rule-set algorithm. Vigor maps of trees’ canopies based on several vegetation indices (VIs) were analyzed to verify whether variations in soil parameters measured in the field correspond to differences in vigor derived from spectral analysis of the canopies.