Deposition law of flat fan nozzle for pesticide application in horticultural plants

Abstract

Pesticide spraying is to protect the plants with adequate target coverage and a minimum of off-target drift. Understanding the spatial distribution characteristics of spray droplets is essential for regulating pesticide deposition, in order to investigate the relationship between the two at the mechanistic level and provide an accurate basis for nozzle selection, this study compared the characteristics of the atomization field under different pressures, angles, and flow rate types by phase Doppler particle analyzer (PDPA), the unit spatial density of droplet was used as a link to explore the internal mechanism that affects the deposition efficiency by constructing a transport model and conducting actual spraying experiments. The results showed that the cumulative distribution of droplet diameter could be perfectly fitted by the Rosin-Rammler correlation, and the deposition efficiency had a strong correlation with the peak particle size range. For strawberry and chrysanthemum plants, the optimal droplet deposition particle size ranges were 250-270 μm and 240-260 μm, respectively. This article explained the deposition efficiency from a single droplet dynamics mechanism and deposition of droplet cloud, which provided a new research idea for the study of precision plant protection.

Back pressure generated by downwash and crosswind on spatial atomization characteristics during UAV spraying: CFD analysis and verification

“…According to the exploration of the difference of droplets by spatial atomization, this study considered the particle size requirements of spray droplets to propose the strategy of pesticide spray. By changing the relation between the spraying height and the droplet size, different spraying requirements can be met, such as: using liquid pollen spray for small droplets for pear tree, 41 using herbicide of large droplets for weeds 42 and using medium‐sized droplets for strawberries 43 . In order to resist the drift and atomization stratification by crosswind, it is necessary to increase the application height, increase the downwash airflow, and control the UAV to drift against the direction of spray area.…”

Droplet Deposition and Efficacy of Real-Time Variable-Rate Application of Herbicides at Reduced Dose in Winter Wheat Fields

“…In particular, the nozzle is an important component in intelligent spraying machines that ensure spraying quality. It has significant effects on droplet size, coverage on target plant surfaces, and droplet deposition characteristics [25][26][27][28]. Selecting the appropriate nozzle type or size and determining the right spraying volume are effective strategies to increase the number of droplets arriving at the target weeds and decrease the waste of herbicide solutions, thereby improving the utilization efficiency of herbicides and reducing pollution in agricultural environments.…”