Calibration of orchard sprayers – the parameters and methods

According to the new EU directive on sustainable use of pesticides (EC 2009/128) calibration of sprayers has to be implemented in the EU Member States. It is also required in the environmental and operators’ safety context of different documents and guidelines determining the implementation of good practices or the compliance with standards of certified crop production. The most recent guidelines underline the up-to-date opinion that calibration of sprayer should optimise the on-crop product deposition, and reduce the off-target loss of pesticides. Therefore calibration for orchard sprayers should in particular include aspects regarding spray volume determination, airflow adjustment and selection of the type, number and configuration of nozzles, aiming at high spray application quality and its environmental impact. Spray volume adapted to specific orchard may be calculated based on Tree Row Volume concept. The air flow setting includes adjustment of air volume/velocity, air flow range and air- flow direction/deflection. The type, number and configuration of nozzles are selected aiming at enhanced deposition and distribution of spray in the crop canopy, and reduced spray drift. The practical methods of calibration considering these aspects are proposed in this paper.