## 4 Conclusions  
Spray application efficiency is related to the capability to minimize spray losses to the ground and the air, while still guaranteeing a good level of spray coverage and deposition throughout the canopy. In this respect, a sprayer for bed-grown carrots, employing variable nozzle spacing and boom height to match the target zone width at different crop stages, was developed within the H2020-project OPTIMA. A first step was to select various nozzle types and configurations and the most optimal nozzle spacing and boom height. Four most promising bed spray configurations were tested in terms of spray deposition, ground losses and spray drift potential and compared to the reference broadcast application in semi-field conditions. The bed spray configurations resulted in higher relative canopy depositions and ground losses under the canopy, both at early-stage and full-grown carrots, due to relatively more spray being directed to the target zone compared to the broadcast application. Spray drift potential was closely related to nozzle type and droplet size spectrum, with increased drift potential for fine sprays and large drift potential reductions with air inclusion nozzles, even despite higher spray boom height than the reference broadcast application. It can be concluded that bed spray configurations can improve canopy depositions and limit spray drift potential compared to a conventional broadcast application, when the boom height and the nozzle spacing are adjusted according to the growth stage. Especially the configuration with air inclusion nozzles in combination with off-center nozzles, i.e., AIUB8504, resulted in high canopy depositions and drift reduction potential. The use of air support had no significant effect on spray deposition or spray drift potential, probably because of the relatively low airflow velocities. In a next step, the use of variable nozzle spacing and air support will be studied under real field conditions using the most promising configurations.  
**Author Contributions:** Conceptualization, A.L., J.-P.D. and I.Z.; methodology, A.L. and J.-P.D.; validation, formal analysis, I.Z., D.N. and M.G.; investigation, A.L. and J.-P.D.; resources, A.C.; writing--original draft preparation, A.L. and J.-P.D.; writing--review and editing, I.Z., P.B., P.M., M.G., N.M., S.F. and D.N.; project administration, N.M. and S.F. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by European Union's Horizon 2020 research and innovation program under grant agreement number 773718 (OPTIMA-project).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available upon request from the corresponding author. Data will become openly available in a public repository that issues datasets with DOIs (i.e., Zenodo platform) in the following weeks, in line with the Horizon 2020 project requirements.  
**Acknowledgments:** Planete Vegetal SCEA Le Pot au Pin, Cestas 30610, France, Invenio, Ychoux 40160, France, AAMS BV, Madelgem, 9990; Belgium and Salvarani Srl, Poviglio (RE), Italy are acknowledged for the furniture of experimental material and practical support.  
**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.