Search Results (12)

Electrostatic spraying systems can improve the pesticide application efficiency by enhancing droplet deposition and coverage within crop canopies. This study evaluated the droplet size spectra and charge-to-mass ratio (CMR) of five electrostatically charged hollow-cone nozzles and one flat-fan nozzle paired with an electrode. Each nozzle was mounted on a moving boom in a wind tunnel and operated with the electrode and voltage that produced the highest CMR. Their effects on the spray coverage and deposition inside boxwood shrubs at wind speeds of 0 and 2.24 m s⁻¹ were assessed. The nozzles operated with the optimized electrode had average improvements in the canopy deposition and canopy coverage of 1.33 µg cm⁻² and 4.4% at a wind speed of 0 m s⁻¹ and 0.26 µg cm⁻² and 0.9% at a wind speed of 2.24 m s⁻¹. The airborne drift measurements at various heights above the wind tunnel floor showed an average 0.50 µg cm⁻² reduction in the drift at 0.1 m, variable results at 0.35 m, and minimal changes at heights of 0.7 m and above at a downwind distance of 2 m. These findings highlighted the potential of optimized electrostatic spraying systems to enhance pesticide deposition inside the crop canopy under various wind speeds while reducing the spray drift potential. Full article

The development of unmanned aerial spraying systems (UASSs) has significantly transformed pest and disease control methods of crop plants. Precisely adjusting pesticide application rates based on the target conditions is an effective method to improve pesticide use efficiency. In orchard spraying, the structural characteristics of the canopy are crucial for guiding the pesticide application system to adjust spraying parameters. This study selected mango trees as the research sample and evaluated the differences between UAV aerial photography with a Structure from Motion (SfM) algorithm and airborne LiDAR in the results of extracting canopy parameters. The maximum canopy height, canopy projection area, and canopy volume parameters were extracted from the canopy height model of SfM (${CHM}_{SfM}$) and the canopy height model of LiDAR (${CHM}_{LiDAR}$) by grids with the same width as the planting rows (5.0 m) and 14 different heights (0.2 m, 0.3 m, 0.4 m, 0.5 m, 0.6 m, 0.8 m, 1.0 m, 2.0 m, 3.0 m, 4.0 m, 5.0 m, 6.0 m, 8.0 m, and 10.0 m), respectively. Linear regression equations were used to fit the canopy parameters obtained from different sensors. The correlation was evaluated using $R^2$ and $rRMSE$, and a t-test (α = 0.05) was employed to assess the significance of the differences. The results show that as the grid height increases, the $R^2$ values for the maximum canopy height, projection area, and canopy volume extracted from ${CHM}_{SfM}$ and ${CHM}_{LiDAR}$ increase, while the $rRMSE$ values decrease. When the grid height is 10.0 m, the $R^2$ for the maximum canopy height extracted from the two models is $92.85\%$, with an $rRMSE$ of $0.0563$. For the canopy projection area, the $R^2$ is 97.83%, with an $rRMSE$ of 0.01, and for the canopy volume, the $R^2$ is 98.35%, with an $rRMSE$ of 0.0337. When the grid height exceeds 1.0 m, the t-test results for the three parameters are all greater than 0.05, accepting the hypothesis that there is no significant difference in the canopy parameters obtained by the two sensors. Additionally, using the coordinates $x_0$ of the intersection of the linear regression equation and $y=x$ as a reference, ${CHM}_{SfM}$ tends to overestimate lower canopy maximum height and projection area, and underestimate higher canopy maximum height and projection area compared to ${CHM}_{LiDAR}$. This to some extent reflects that the surface of ${CHM}_{SfM}$ is smoother. This study demonstrates the effectiveness of extracting canopy parameters to guide UASS systems for variable-rate spraying based on UAV oblique photography combined with the SfM algorithm. Full article

The phenomenal growth of remotely piloted aerial application systems (RPAASs) in recent years has raised questions about their impact on the off-target movement of plant protection products. The spray droplet spectrum is one of the important determining factors that govern droplet trajectories and off-target movement of pesticide particles. A field study was conducted to compare in-swath and downwind spray deposition on ground samplers from a 20 L RPAAS platform, equipped with three different nozzles, which provided fine, medium, and extra-coarse droplet spectra. A fluorescent dye was used as a tracer to determine spray deposition. Airborne spray droplets were measured at 10 and 20 m downwind. Downwind deposition measured on ground samplers showed that the extra-coarse nozzle received significantly fewer deposits than the medium or the fine nozzle. Similarly, the airborne deposition for the extra-coarse nozzle was significantly less compared to either the fine or the medium nozzle. Linear mixed effects modeling confirmed these results and showed that wind speed served as a covariate by refining the deposition differences among nozzles. Results indicated that spray drift from RPAAS platforms may be mitigated by using appropriate nozzles that produce larger droplet spectra. These results will provide aerial applicators with a better understanding of the best management practices to mitigate drift. Full article

Policies aimed at reducing plant protection products (PPPs) are part of the UN’s 2030 Agenda for Sustainable Development. Sustainable management of PPPs is crucial for soil health, biodiversity, and ecosystem services, including food provision. While PPPs can control pests and enhance agricultural yields, they also pose environmental and health risks by contaminating water, soil, and non-target organisms through airborne drift. Investigating innovative and more sustainable distribution methods can support sustainability goals. This study aimed to evaluate the potential impact of the pesticide Spintor^® Fly on non-target soil organisms in olive orchards comparing two spraying methods: a traditional Casotti^® pump mounted on a tractor and an innovative Unmanned Aerial Vehicle (UAV) developed for the project. The study was conducted in 2021 in an organic olive orchard, which was divided into two plots: a Casotti-treated plot (CAS) and a drone-treated plot (DRO). A strip of uncultivated land at the edge of the orchard was used as a (non-treated) control plot (CAP). The impact on native soil microarthropod communities was assessed using the arthropod-based Soil Biological Quality Index (QBS-ar) and Bait Lamina Test (BLT). Soil samples were collected for earthworm avoidance tests and soil chemical–physical analysis. The results obtained with QBS-ar and BLT indicated no significant differences between DRO and CAS, in both sampling periods (pre- and post-treatment). However, DRO generally exhibited slightly better performance than CAS. The avoidance behaviour was confirmed for both CAS and DRO, although it was lower for the latter. Overall, drone aerial spray performed slightly better, suggesting a potentially lower impact on soil communities. Our results provide initial clues for the sustainable use of drones in agriculture with no increased risks for soil health compared to traditional methods. Further long-term studies should be conducted to validate these findings and possibly confirm the long-term benefits of drone applications compared to traditional methods. Full article

Efficient collection of airborne spray is crucial to reduce environmental contamination and ensure effective pesticide application in agriculture. This study explored the efficacy of passive spray drift samplers, focusing on string collectors for capturing airborne spray droplets. String collectors were assessed in laboratory experiments using a spray drift tunnel. A notable average recovery rate of 82% was observed when string collectors were examined immediately after pesticide capture. Collection efficiency was found to increase with wind speed. Of all the string collectors, string #5, a yarn type, demonstrated consistent collection efficiency, meeting the criteria for passive samplers. This includes effective droplet capture at low wind speeds, a high recovery rate of 93.31%, and suitability for field experiments. Field evaluations further underlined the efficiency of string #5, showcasing its ability to capture spray drift across a wider area and varied heights with less effort and manpower compared to traditional nylon screens. Full article

This critical review examines the release of pesticides from agricultural practices into the air, with a focus on volatilization, and the factors influencing their dispersion. The review delves into the effects of airborne pesticides on human health and their contribution to anthropogenic air pollution. It highlights the necessity of interdisciplinary research encompassing science, technology, public policy, and agricultural practices to effectively mitigate the risks associated with pesticide volatilization and spray dispersion. The text acknowledges the need for more research to understand the fate and transport of airborne pesticides, develop innovative application technologies, improve predictive modeling and risk assessment, and adopt sustainable pest management strategies. Robust policies and regulations, supported by education, training, research, and development, are crucial to ensuring the safe and sustainable use of pesticides for human health and the environment. By providing valuable insights, this review aids researchers and practitioners in devising effective and sustainable solutions for safeguarding human health and the environment from the hazards of airborne pesticides. Full article

In the past decade, an unmanned aerial spraying system (UASS) was applied more and more widely for low-volume aerial pesticides spraying operations in China. However, UASS have a higher drift risk due to more fine droplets sprayed with a higher working height and a faster driving speed than ground sprayers. Study on UASS spray drift is a new hot spot within the field of pesticide application technology. The field test bench was originally designed and applied for the measurement of the spray drift potential of ground sprayers. No methodology using the test bench for UASS drift evaluation was reported. Based on our previous study, field drift measurements of an eight-rotor UASS were conducted using three techniques (test bench, ground petri dish, and airborne collection frame) in this study, and the effects of meteorological parameters and nozzle types were investigated, to explore the applicability and the feasibility of the test bench used in UASS field drift evaluation. The test bench is proven promising for direct drift determination of UASS and the described methodology enabled classification of different UASS configurations. Higher wind speeds and finer droplets produced higher drift values. The faster the wind speed and the lower the humidity, the more the spray drift. The test bench can reduce the site requirements and improve the efficiency of the field drift test. Full article

Pesticide application is essential for improving crop productivity; however, undesirable pesticide drift must be mitigated because of its adverse impacts on humans, the environment and ecosystems. The collection and accurate quantification of airborne droplets are key elements involved in identifying the spatial and temporal dispersion of off-target spray movement. Various types of passive and active collectors have been deployed to measure airborne spray drift; however, the collection efficiencies of only a few samplers have been verified. This study evaluated the collection efficiency of two airborne-spray-drift collectors using an experimental drift wind tunnel. The airborne spray drifts were quantified by a total organic carbon analyser and validated by comparison to measurements using liquid chromatography with tandem mass spectrometry. Computational fluid dynamics (CFD) simulations were used to explore the effects of droplet size and wind speed on the collection performance. It was found that nylon screens, passive samplers, captured 57.9–88.1% of the airborne spray drift. These results are considered reliable and are comparable to those found in the literature. Additionally, the CFD results demonstrated that the collection efficiency increased with droplet diameter. An increase in wind speed improved the collection efficiency of fine droplets (≤100 μm diameter); however, wind speed had no significant influence on the collection of coarse droplets. These measurements, alongside the aerodynamic approach adopted in this study, can provide a comprehensive understanding of the collection performance of nylon screens. Full article

When pesticides are sprayed, a significant portion of the droplets drifts away from the target. Using an adjuvant in spray liquid is an easy option for reducing droplet drift because there is no need to make any changes to the sprayer. The objective of the study was to determine the effects of seven commercially available adjuvants (Surfeco plus, Starguar, Kantor, Sterling, Control, Control WM, and Control DUO) with varying active ingredients on droplet size, surface tension, and viscosity. Since these properties affect droplet formation, these adjuvants were evaluated in terms of their drift-reducing performance in a wind tunnel at various wind speeds (2.0, 3.5, and 5.0 m/s) and spray pressures (3, 4, and 5 bars). The ground and airborne components of drift were evaluated. With the use of a patternator, the potential for the ground drift of adjuvants was measured; for airborne drift, polyethylene lines that were stretched along the cross-section area of the wind tunnel at various heights were employed. The number of deposits of a tracer dye–adjuvant mixture that was sprayed on the polyethylene lines was measured via fluorometric methods for determining the airborne drift potential. The test results showed that the adjuvant Control Duo containing a polymer blend, which had the highest dynamic viscosity (4.27 mPa.s), increased the Dv_0.5 droplet diameter up to 192 μm at 3 bar with nozzle XR11002. This adjuvant reduced the ground drift potential (D_c) by 60.53% compared to tap water. The maximum airborne drift potential reduction percentage (DPRP) was obtained as 85.76% with Surfeco plus containing organic silicone at a pressure of 3 bar and a wind velocity of 5 m/s. When considering the airborne drift-reduction potential of the adjuvants used, it was found that the adjuvants Control WM, Control, Starguar, and Surfeco plus significantly reduced the airborne droplet drift compared to spraying tap water. Full article

Aerial electrostatic spray technology for agriculture is the integration of precision agricultural aviation and electrostatic spray technology. It is one of the research topics that have been paid close attention to by scholars in the field of agricultural aviation. This study summarizes the development of airborne electrostatic spray technology for agricultural use in China, including the early research and exploration of Chinese institutions and researchers in the aspects of nozzle structure design optimization and theoretical simulation. The research progress of UAV-based aerial electrostatic spray technology for agricultural use in China was expounded from the aspects of nozzle modification, technical feasibility study, influencing mechanism of various factors, and field efficiency tests. According to the current development of agricultural UAVs and the characteristics of the farmland environment in China, the UAV-based aerial electrostatic spray technology, which carries the airborne electrostatic spray system on the plant protection UAVs, has a wide potential in the future. At present, the application of UAV-based aerial electrostatic spray technology has yet to be further improved due to several factors, such as the optimization of the test technology for charged droplets, the impact of UAV rotor wind field, comparison study on charging modes, and the lack of technical accumulation in the research of aerial electrostatic spray technology. With the continuous improvement of the research system of agricultural aviation electrostatic spray technology, UAV-based electrostatic spray technology will give play to the advantages in increasing the droplets deposition on the target and reducing environmental pollution from the application of pesticides. This study is capable of providing a reference for the development of the UAV-based agricultural electrostatic spray technology and the spray equipment. Full article

Unmanned Aerial Vehicles (UAVs) have been widely applied for pesticide spraying as they have high efficiency and operational flexibility. However, the pesticide droplet drift caused by wind may decrease the pesticide spraying efficiency and pollute the environment. A precision spraying system based on an airborne meteorological monitoring platform on manned agricultural aircrafts is not adaptable for. So far, there is no better solution for controlling droplet drift outside the target area caused by wind, especially by wind gusts. In this regard, a UAV trajectory adjustment system based on Wireless Sensor Network (WSN) for pesticide drift control was proposed in this research. By collecting data from ground WSN, the UAV utilizes the wind speed and wind direction as inputs to autonomously adjust its trajectory for keeping droplet deposition in the target spraying area. Two optimized algorithms, namely deep reinforcement learning and particle swarm optimization, were applied to generate the newly modified flight route. At the same time, a simplified pesticide droplet drift model that includes wind speed and wind direction as parameters was developed and adopted to simulate and compute the drift distance of pesticide droplets. Moreover, an LSTM-based wind speed prediction model and a RNN-based wind direction prediction model were established, so as to address the problem of missing the latest wind data caused by communication latency or a lack of connection with the ground nodes. Finally, experiments were carried out to test the communication latency between UAV and ground WSN, and to evaluate the proposed scheme with embedded Raspberry Pi boards in UAV for feasibility verification. Results show that the WSN-assisted UAV trajectory adjustment system is capable of providing a better performance of on-target droplet deposition for real time pesticide spraying with UAV. Full article

Spray drift assessment encompasses classification of the capacity of each sprayer/technology/setting combination to reduce or avoid the spray drift risk, as well as drift measurement to define buffer zones mandated during pesticide application. Compounding the challenge of these tasks is the great variability of field evaluation results from environmental conditions, spray application technology, canopy structure, and measurement procedures. This study, performed in Spanish context, evaluates the effects of different parameters on comparative measurements of ground and airborne spray drift employing the ISO22866:2005 protocol. Four configurations of air blast sprayers, derived from two fan airflow rates and two nozzle types (conventional and air-induction), were tested in orchard and vineyard at late growth stage. Spray drift curves were obtained, from which corresponding Drift Values (DVs) were calculated using an approximation of definite integral. Both sprayer settings and environmental variables statistically affect spray drift total amounts and result variability. PCA analysis showed that nozzle type and wind speed characteristics explained 51% and 24% of the variance, respectively. In particular, mean wind direction influence ground sediments (Pr < 0.01) and maximum wind speed strongly influence airborne drift value (Pr < 0.0001). The wind characteristics concealed the influence of adopted fan airflow rates on final spray drift assessment results. The effect of uncontrollable environmental conditions makes objective and comparative tests difficult. Full article