Utilization of proximal sensing technology (GreenSeeker) to map variability in Ontario vineyards

Abstract

Precision agriculture is a term used to describe a popular amalgam of technologies employed for the optimization of production in agronomic crops. Over the past decade, these technologies have been applied to viticulture, including use of GPS, construction of maps using GIS, yield monitors on mechanical harvesters, remote sensing, and surface-based assessment of foliar health. Much of this technology has also been examined for its use in assessment of vine water status and berry composition. This project was intended to assess a recent technology, the GreenSeeker^TM (Trimble Corp.) and assess its usefulness by correlating those metrics it provides (based on horizontally-accessed spectral reflectance) to both yield, yield components such as cluster weight and berry weight, vine and soil water status, and berry composition. Three experimental sites were chosen (Lambert Vineyards, Niagara-on-the-Lake, ON; Coyotes Run, St David’s, ON; Cave Spring Vineyards, Beamsville, ON). The Lambert and Cave Spring sites each contained Riesling and Cabernet franc study blocks while the Coyotes Run site had two Pinot noir study blocks. A grid of geolocated sentinel vines was chosen for each study block. Soil moisture and leaf water potential (ψ) measurements were collected between fruit set and veraison. GreenSeeker^TM measurements were likewise collected from lag phase to just prior to harvest. Yield and berry composition measurements were collected from each sentinel vine. Preliminary data indicate that linear correlations and spatial correlative relationships were apparent between NDVI data collected by GreenSeeker^TM and both soil moisture and leaf ψ, in addition to yield components and berry composition. Furthermore, zones indicative of virus infection (grapevine leafroll 3) could be defined using this technology. Tentative conclusions are that GreenSeekerTM technology will be useful for delineation of management zones within vineyards for ultimate application of precision viticulture.