Variable rate technology as a site-specific management strategy on slope vineyards

Variable rate technology (VRT) is an emerging technology that allows the targeted application of agronomic inputs based on temporal and spatial variations. In vineyards, characterized by inherent heterogeneity due to structural, agronomic, and weather factors, precise canopy analysis is vital for optimizing the use of plant protection products (PPP). Quinta do Seixo in the Douro region, offers unique microclimates, shaped by rugged orography and steep slopes, causing terraced vineyards along slopes to alternate concavities created by water lines with convexities and inducing alternate areas of respectively high and low vigour in the same row of vines.

VRT follows 3 key steps:

(1) data collection through proximal or remote sensing (satellite, aircraft, tractors and unmanned aerial or ground vehicles) to obtain imagery of grapevine vegetation;

(2) data interpretation, converting imagery into indices such as Normalised Difference Vegetation Index (informing on vegetation biomass) or Normalised Difference Red Edge Index (informing on vegetation chlorophyll contents), creating canopy maps, spatially represented using Geographic Information Systems (GIS) converted by Decision Support Systems (DSS) software into applied prescription maps;

(3) onboard computer (VRT 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, visualise, and analyse data from sprayer applications, assessing efficiency and compatibility with modern agronomic approaches, especially in steep slope vineyards.