Droplets deposition pattern from a prototype of a fixed spraying system in a sloping vineyard.

In Italy high-quality vines are sometimes grown in small fields with slope steeper than 5-10%, where an air-blast sprayer is impractical so spray-gun application of pesticides is used, a technique that is very costly and labour intensive, and that causes high pesticide exposure of the operators. A possible alternative is the use of a fixed spraying system, and the first researches are in progress in Italy. A fixed spraying system prototype was built in a vineyard at Laimburg Research Centre with an upper line with micro-sprinkler and a lower line with cooler-type nozzles, and a trial was performed with the aim of measuring the deposition pattern of droplets on the row and between rows with water sensitive papers, also in comparison with a precise low-drift air-blast sprayer. Results show that with the fixed spraying system the treated crop row accounts for 38-44% of total deposition, that about 85-88% of sprayed solution falls on the sprayed row and on the closest right and left adjacent inter-rows, and that at 4 m from the spraying line the spray drift was <0.1%. This highlights that a fixed spraying system has the potential to apply plant protection products without generating drift problems, with a field performance similar to a low-drift sprayer, becoming an opportunity for vineyards on very steep slopes.