Fertilisers and plant protection products application have changed in recent years due to the European Directive for Sustainable Use of Pesticides (2009/128/EC). Towards more sustainable agriculture, a reduction of contentious pesticides is required. This can be obtained by developing innovative eco-friendly strategies. One of these strategies is variable rate technology that supports vineyard management minimizing spray losses, applying precise amounts according to previously collected data, such as canopy size, weather, and phenology. Trials under the NOVATERRA project are being carried out at vineyards in Quinta do Seixo (property of SOGRAPE), a mountain viticulture region.
Variable rate technology (VRT) is an emerging technology allowing to differentially apply agronomic inputs in time and space. Vineyards have usually high heterogeneity due to structural factors, cropping practices and seasonal weather, accurate canopy characterization being crucial for efficient use of plant protection products (PPP). Quinta do Seixo, in Douro region, offers unique microclimates, due to rugged orography and steep slopes, causing terraced vineyards along slopes to alternate concavities created by water lines with convexities, inducing alternate areas of respectively high and low vigor in the same row of vines. VRT follows 3 steps: (1) data collection, by proximal or remote sensing (satellite, aircraft, tractors and unmanned aerial or ground vehicles), obtains imagery of grapevine vegetation; (2) interpretation of data, converting imagery into indices such as normalized difference vegetation index (NDVI, informs on vegetation mass) or normalized difference red edge index (NDRE, informs on vegetation chlorophyll) canopy maps (Figure 2), spatially represented using geographic information systems (GIS) converted by decision support systems (DSS) software, into applied prescription maps; (3) onboard computer (VRA controller of tractor sprayer) with software coupling data from GNSS/GPS (global navigation satellite system / global positioning system) with prescription maps to control spray application. A smart platform is planned to combine these technologies, visualize and analyze data from sprayer application to assess its efficiency, meant also to work steep slope vineyards and compatible with modern agronomic approaches.