Developing an ISO11783-compliant prescription map for variable rate spraying in vineyards based on 3D canopy reconstruction

The use of the ISO11783 standard (commonly designated as ISOBUS) for communication between tractor and implement is not yet widespread in specialty crops compared to arable farming. With the advent of the digital era in viticulture and the use of increasingly complex implements from different manufacturers, a standardised communication interface is essential. In addition to interoperability between operating terminal, tractor and various implements, ISOBUS provides interfaces and tools for more efficient and precise agricultural practices. This is crucial for the precise application of plant protection products, which is becoming increasingly important for economic and environmental reasons. Besides that, a variable rate application (VRA) can enhance precision and offer a potential solution to significantly reduce costs and environmental impact, ensuring a more sustainable approach to viticulture.This paper proposes a methodology to develop a prescription map for ISOBUS-compliant sprayers in vineyards based on leaf wall area (LWA) predictions from three dimensional (3D) point clouds generated by a light detection and ranging (LiDAR) sensor. The methodology aims to create VRA maps ensuring demand-oriented treatments adapted to canopy heterogeneity. The study investigates LiDAR measurement uncertainties by analysing a rectangular board with known dimensions under realistic scenarios, as well as discrepancies between the LWA predictions and manual ground-truth measurements. The prescription map was tested using an ISOBUS compatible operating terminal and a prototype sprayer.The analysis of the rectangular board showed a maximum RMSE of 8.3 % for height determination. A strong correlation (R² = 0.92) between the manually measured leaf areas and the number of points in the generated LiDAR 3D point cloud was determined. This correlation's linear regression was used to calculate dose rates, leading to the successful development of a grid-based prescription map in ISO-XML format, compatible with ISOBUS Task Controller functionality. The resulting map enables variable dose rates per meter of the leaf wall, allowing independent adjustments for the left and right sides of the sprayer simultaneously.