Measure of spray deposition in a 'tendone' vineyard produced by an air blast sprayer machine

This study reports the main results of a research aimed at evaluating the effects of airflow rate and volume rate on foliar deposits in a 'tendone' vineyard when using an air blast sprayer with two counter-rotating fans and anterior intake. Experimental tests were replicated in two phenological stages (full flowering and berry touch), characterized by different Leaf Area Indices (2.21 and 5.83 m2 m-2), considering two airflow rates (2.43 and 5.71 m3 s-1), two volume rates (about 335 and 625 L ha-1) and keeping the forward speed constant (1.1 m s-1). Before tests, the sprayer was calibrated using a patternator purposely designed for 'tendone' vineyards, achieving a distribution profile in agreement with the vineyard Leaf Area Index pattern. The results showed that foliar deposits were not affected by volume rate at either phenological stage, whereas increasing the airflow rate, they decreased significantly at full flowering (-30 % on the most exposed vegetation), and increased significantly at berry touch (+43%).