Design and Evaluation of Solid Set Canopy Delivery System for Spray Application in High-density Apple Orchards

Abstract

Abstract. Permanent or solid set canopy delivery (SSCD) system with certain types of emitters placed along the tree rows have shown promise in the past for foliar application in tree fruit orchards. However, limited knowledge exists in terms of designing a SSCD system for uniform canopy spray coverage in tree fruit orchards. This study examined the spray coverage in high-density, super spindle apple orchards created by different nozzles and their configuration within a canopy on a SSCD system. Three different types of emitters (sprinkler, full cone, and hollow cone) and two different design configurations were evaluated in the orchard using three consecutive tree fruit rows that were 9 m long. Application pressures were 241, 379, and 517 kPa. Coverage analysis on the upper- and under-side of leaves was determined using water sensitive cards (WSC) on three randomly selected trees (23= cards/tree). The results indicated that the design configuration with two 80° hollow-cone nozzles, installed at three different canopy heights, and spray application pressure of 379 kPa provided greater coverage on upper-side (87%) and on the under-side (50%) of tree leaves. Additional studies would have to be conducted for other fruit crops and training systems to optimize system design for intended spray coverage. Keywords: Application pressure, Emitter, Solid set canopy delivery, Spray nozzle, Spray coverage.