Assessment of spray drift potential reduction for hollow-cone nozzles: Part 2. LiDAR technique

Pesticide spray drift poses health hazards to humans and causes a significant impact on the environment. In this work the capacity of an ad hoc light detection and ranging (LiDAR) system to differentiate spray nozzles according to their potential drift risk is evaluated for the first time. A total of 23 drift potential tests using 10 hollow-cone nozzles were carried out with the sprayer kept in a static position. Drift potential reduction (DPR) values of between 88.6% and 93.6% were obtained when comparing standard and drift reduction nozzle types. It was also possible to order different standard nozzle sizes according to their DPR. The LiDAR signalwas correlated with several droplet size parametersmeasured by a phase Doppler particle analyzer (PDPA), being V100 the best indicator. In the four field tests thatwere performed, the LiDAR systemwas also able to differentiate between standard and drift reduction nozzles under real application conditions, obtaining a DPR of 56.7%. The results of this work demonstrate that the developed LiDAR system is an advantageous alternative for the assessment of drift potential reduction.This work was partly funded by the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya, the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (ERDF) under Grants 2017 SGR 646, AGL2007-66093-C04-03, AGL2010-22304-04-C03-03, and AGL2013-48297-C2-2-R. Universitat de Lleida is thanked for Mr. X. Torrent's pre-doctoral fellowship. The authors would like to thank the Unité Mixte de Recherche Information & Technologies for AgroProcess (IRSTEA, Montpellier), and particularly Jean-Paul Douzals and Cyril Tinet for the nozzle characterization using their PDPA. Our thanks are also given to the Institut de Recerca en Tecnologia Agrària (IRTA) for allowing the use of their experimental fields, and to Vicenç Maquinària Agrícola for providing the tractor. The authors also wish to thank A. Checa (Randex Iberica, S.L.) for giving us free Albuz nozzles for the spray tests. R. Lavilla, E. Ordoño and F. Solanelles are acknowledged for their assistance in the field work, and J. Arnó is thanked for his help with statistical analysis