The influence of the exploitation period on the proper operation of nozzels – the constituent element of orchard sprayers

The successful implementation of chemical protection depends on two main factors. The first factor relates to the selection of the compound and its application in adequate time, while the second factor relates to the technical functionality of the parts of the machines used for the application of the protective liquid, i.e. the nozzle. The technical functionality of the sprayer elements, the proper tuning (calibration) and the correct selection of the nozzle all have a great influence on the proper functionality of the sprayer elements. The proper technical functionality of the sprayer is a prerequisite for the effective application of the protective liquid, for the financial savings and the environmental protection as well as. In our practice, a particular problem is the fact that agricultural producers do not perform regular annual controls on both the nozzles themselves and the other elements of the sprayers. This paper presents a comparative analysis of several types of sprayers, which have the same type of nozzles, but with different factory declared flow. 25 sprayers were tested and divided into four groups according to the exploitation period. In the first group of sprayers the nozzles were within the factory declared flow rate (100% correct), while the fourth group of sprayers had half of the nozzles (50% defective) for replacement. This research shows that the length of the exploitation significantly influences on the technical functionality of the sprayers. In order for as many sprayers as possible to meet the technical standards of EN 13790 to be applied in practice, it is necessary to regularly check the technical functionality of the nozzles, and all other elements of the sprayers by the users themselves, and periodically also by the authorized laboratories