Vertical spray patterns for sprayer calibration

A vineyard sprayer was calibrated using a lamellae patternator to produce either a “canopy pattern”, derived from the canopy outline, or a “projection pattern”, derived from projection of the canopy crosssection in the directions of the spray fluxes. Both calibration methods were compared with nozzle adjustment in the field, and applied in a hedgerow vineyard, at beginning of flowering and at full foliage development (berries pea-sized). Spray deposits at different heights on the canopy were determined by colorimetry, using a water-soluble dye (Tartrazine) as a tracer. The results showed that the “projection pattern” can be recommended for a general sprayer calibration performed at a public test centre with reference to a full foliage growth stage of the vine, but methods for sprayer calibration in the field are also necessary, owing to the difficulty of forecasting the canopy size and geometry at the earlier stages.