Boom sprayer optimizations for bed-grown carrots at different growth stages based on spray distribution and droplet characteristics.

BACKGROUND: Pesticide losses and uneven spray distribution should be avoided as much as possible as they reduce the effectiveness of spraying and increase environmental contamination as well as costs. Within the H2020-project OPTIMA the goal is to develop a smart sprayer for bed-grown carrots, including optimizations such as air support and variable nozzle spacing. This paper focuses on selecting the most optimal nozzle types, spacing and height for spraying bed-grown crops, while taking into account different target zone widths depending on the growth stage, based on spray distribution and droplet characterization measurements. RESULTS: The results indicate that four bed spray configurations consisting of four nozzles per bed, i.e. XR8004/XR8004/XR8004/XR8004, AIUB8504/AI11004/AI11004/AIUB8504, AI8004/AI8004/AI8004/AI8004 and XR8002/XR8002/XR8002/XR8002, spraying at 300 kPa and recalculated to 12.0 km h-1 forward speed, are appropriate for spraying different target zone widths (ranging from 1.2 to 2.2 m) with high uniformity (CV < 12%) and minimal losses out of the target zone (<17%) when applied at the most appropriate nozzle spacing and height (varying from 0.35 to 0.65 m). Droplet characterization measurements showed that for the same nozzle size and spray pressure, air inclusion nozzles produced larger but slower droplets than standard flat-fan nozzles. Air support increased the droplet velocities but had only a very limited effect on droplet size. CONCLUSION: Laboratory spray distribution and droplet characterization measurements allowed selection of the most optimal nozzle type, spacing and height for bed spray applications in terms of reduced pesticide losses compared to conventional broadcast applications. © 2022 Society of Chemical Industry.

Using an Online Platform to Administer the Single-Session Point Subtraction Aggression Paradigm: An Initial Examination of Feasibility and Validity.

Online platforms represent a cost-effective option for data collection; however, it is unclear whether online administration of certain kinds of tasks (e.g., behavioral measures of aggression) poses validity threats. The present study provided a preliminary examination of effort (as indexed by total number of presses), differential drop-out, and believability of an online version of the single-session point subtraction aggression paradigm (PSAP). Two subsamples of participants were recruited; a sample recruited through Amazon's Mechanical Turk (n = 758) and an in-person undergraduate sample (n = 88). All participants completed the PSAP, along with measures of trait hostility and state anger. The online sample did not differ from the in-person sample on effort (i.e., total number of presses), and did not find the task less believable. Higher scores on state anger were associated with lower likelihood of beginning the online PSAP, but were not associated with prematurely closing the task. State anger was related to aggressive responding on the PSAP. Limitations of the online PSAP and considerations for future research are discussed.

Volatilisation of pesticides under field conditions: inverse modelling and pesticide fate models.

BACKGROUND: A substantial fraction of the applied crop protection products on crops is lost to the atmosphere. Models describing the prediction of volatility and potential fate of these substances in the environment have become an important tool in the pesticide authorisation procedure at the EU level. The main topic of this research is to assess the rate and extent of volatilisation of ten pesticides after application on field crops. RESULTS: For eight of the ten pesticides, the volatilisation rates modelled with PEARL (Pesticide Emission Assessment at Regional and Local scales) corresponded well to the calculated rates modelled with ADMS (Atmospheric Dispersion Modelling System). For the other pesticides, large differences were found between the models. Formulation might affect the volatilisation potential of pesticides. Increased leaf wetness increased the volatilisation of propyzamide and trifloxystrobin at the end of the field trial. The reliability of pesticide input parameters, in particular the vapour pressure, is discussed. CONCLUSION: Volatilisation of propyzamide, pyrimethanil, chlorothalonil, diflufenican, tolylfluanid, cyprodinil and E- and Z-dimethomorph from crops under realistic environmental conditions can be modelled with the PEARL model, as corroborated against field observations. Suggested improvements to the volatilisation component in PEARL should include formulation attributes and leaf wetness at the time of pesticide application. © 2015 Society of Chemical Industry.