Variable rate sprayer. Part 2-Vineyard prototype: Design, implementation, and validation

The structural characteristics of the canopy are a key consideration for improving the efficiency of the spray application process for tree crops. However, obtaining accurate data in an easy, practical, and efficient way is an important problem to be solved. This paper describes the technical characteristics of a sprayer prototype developed for vineyards, following the principles and previous laboratory tests described in the complementary paper Variable rate sprayer. Part 1 - Orchard prototype: design, implementation and validation. This prototype can modify the sprayed volume application rate according to the target geometry by using an algorithm based on the canopy volume inspired by the tree row volume (TRV) model. Variations in canopy width along the row crop are electronically measured using several ultrasonic sensors placed on the sprayer and used to modify the emitted flow rate from the nozzles in real time; the objective during this process is to maintain the sprayed volume per unit canopy volume (L m(-3)). Field trials carried out at different crop stages for Merlot and Cabernet Sauvignon vines (Vitis vinifera) indicated a good relationship between the applied volume and canopy characteristics. The potential pesticide savings were estimated to be 21.9% relative to the costs of a conventional application. This conclusion is in accordance with the results of similar research on automated spraying systems. (C) 2013 Elsevier B.V. All rights reserved.