Determining Canopy Vigour in G3 Kiwifruit using Remote Sensing and Geographic Information Systems

Abstract

Consumers are increasingly demanding that food producers justify their use of water, fertiliser and agrichemicals. Placing the right inputs, in the right place, at the right time, is sometimes called “Precision Agriculture”. However, the adoption of Precision Agriculture by New Zealand kiwifruit growers, has been constrained in part, by the cost and complexity of monitoring seasonal growth. Therefore, any new technology, that can simply and cost effectively measure canopy vigour in a timely way and relate that to fruit quality and production inputs, will ultimately help improve orchard gate returns and keep consumers happy. Using a multispectral camera and UAV (drone), this study monitored two, G3 kiwifruit orchards over three months. Canopy Chlorophyll Content, was found to be the best proxy for canopy vigour. The vegetation index, EVI2 on its own, explained 67% of the variability in canopy vigour. Adding orchard topography measures, extracted from LIDAR data using GIS software, increased the explanatory power of the best model to 85%. In many respects, remote sensing was found to be superior to historical measurement methods. However, uptake by the kiwifruit industry is likely to be conditional on a better understanding of the relationship between canopy vigour, fruit quality and orchard gate returns. The significant correlations observed between orchard topography and canopy vigour, signal a need for closer integration of Geography and Agricultural Science disciplines, in future kiwifruit research.