Laser technique for measuring droplet size spectrum

Laser technique enables determination of the droplet size spectrum of spray nozzles at various spray pressure values.

The IDEFICS model has been developed for processing the obtained data. The results are used for determination of the drift reduction of low-drift spray nozzles.

Legal regulations have been laid down for spraying field crops. One of the provisions is that  the outer strip of a field may only be sprayed with low-drift nozzles. The status ‘low drift’ of a nozzle type depends on the percentage small droplets in the droplet size spectrum.

The PDPA (Phase Doppler Particle Analyzer) technique, available at PRI, can measure the droplet size spectrum. Data of the droplet size spectrum are subsequently processed with IDEFICS. Taking into account various factors such as weather influence and field conditions, IDEFICS calculates deposition and drift. The model-calculated drift is compared with the reference situation and the nozzles are classified into the classes 50, 75, 90 or 95% drift reduction.


PRI has expertise about measurement of droplet sizes by means of laser techniques and the IDEFICS model has been developed to calculate drift under average weather and field conditions on the basis of PDPA measurements. Practical experience and scientific knowledge are put together in research into drift reduction for sustainable crop protection and care for the environment.