In recent years, the overuse of pesticides and chemical fertilizers in China has become a significant issue, leading to severe environmental pollution and posing risks to agricultural product safety. This has prompted a group of innovative agricultural experts to explore ways to address these problems, particularly through the adoption of precision agriculture techniques. One promising approach involves using plant protection drones for targeted pesticide spraying, which aims to enhance the efficiency of pesticide usage while reducing the overall amounts applied.
Currently, the agricultural industry's primary focus when it comes to precision drone applications lies in accurately controlling the flow of the nozzles. However, there’s often less attention given to the impact of droplet size on the effectiveness of pesticide control, especially in variable applications. Today, let’s delve deeper into how plant protection drones can manage droplet size and flow to optimize pesticide control, improve efficiency, and minimize environmental harm.
Droplet Size – A Critical Factor in Drone Spraying Efficiency
The efficacy of pesticide spraying is closely linked to several factors, including droplet size, drift tendencies, and sedimentation speed. Among these, droplet size is a parameter that is relatively straightforward to control and plays a crucial role in determining the quality of spraying operations performed by plant protection drones.
Properly managing droplet size is essential for minimizing pesticide use while maximizing control outcomes and reducing environmental contamination. As illustrated in the image below, a single large droplet (400 μm) can break down into multiple smaller droplets (e.g., 200 μm, 100 μm, 50 μm), each with distinct properties affecting coverage and adhesion.
[Insert Image: Illustration of droplet fragmentation]
The size of droplets directly influences coverage density and liquid distribution. Smaller droplets increase the number of droplets geometrically, enhancing the likelihood of pesticide adherence to the intended target. This results in more uniform coverage, improved adhesion, and less pesticide wastage due to evaporation or runoff.
Two images further highlight the impact of droplet size on pesticide control:
[Insert Image: Comparison of coarse vs. fine droplet coverage]
Coarse droplets tend to settle quickly, making them less prone to drifting or evaporation. However, they distribute unevenly, adhere poorly to surfaces, and are prone to bouncing off or rolling off the target, reducing the effectiveness of the pesticide and potentially contaminating surrounding environments.
On the other hand, smaller droplets are more susceptible to air currents, which could lead to unintended drift onto nearby crops. Yet, they offer superior coverage density and uniformity on plant leaves, stronger adhesion, and lower risk of loss, translating into higher pesticide efficiency.
Additionally, finer droplets possess better penetration capabilities, allowing them to infiltrate deeper into plant canopies and settle on hard-to-reach areas like the undersides of leaves or dense foliage, where larger droplets might fail to reach. For agents with limited mobility within leaf tissues, atomized fine droplets can boost biological reactions.
In summary, for contact-action pesticides, smaller droplets yield better control outcomes. Finding the ideal droplet size—a balance between settling capability and coverage—is key to optimizing pesticide efficacy. This requires precise droplet size control.
Nozzle Control – Pressure Nozzles vs. Centrifugal Nozzles
During drone spraying operations, the atomization mechanism disperses the pesticide liquid into fine droplets. In this process, the nozzle serves as the central component of pesticide atomization.
Currently, two types of nozzles dominate drone applications: pressure nozzles and centrifugal nozzles. Let’s examine their atomization principles, advantages, and disadvantages.
[Insert Image: Comparison of pressure and centrifugal nozzles]
Overall, centrifugal nozzles excel in droplet size control and atomization quality, making them more effective for pesticide spraying.
Biological Optimal Droplet Size and Pesticide Control Effect
As discussed earlier, finding the right droplet size balance is vital for achieving maximum control. How can we identify this sweet spot?
Research indicates that different biological targets capture droplets within specific size ranges. Within this optimal range, the target encounters the highest number of droplets, resulting in the best control outcome—the “biological optimal droplet size†theory.
Using this theory, tailored droplet sizes and spraying methods can be designed for specific pests, drastically reducing pesticide application rates while boosting control efficiency.
For various biological targets, the optimal droplet size varies depending on the type of pesticide used. The following table illustrates this variation:
[Insert Table: Optimal droplet sizes for different pests and pesticides]
Clearly, droplets that are either too large or too small hinder pest control. Only when droplet size and quantity combine optimally does the best control effect occur.
Of course, the ideal spray droplet size is influenced by numerous factors, including the pest type, pesticide variety, target characteristics, chemical concentration, and even the specific pest species. Variable spraying based on optimal droplet size presents a major challenge in precision dispensing technology.
Solution – Develop Precision and Controllable Variable Droplet Size Systems
To improve pesticide efficiency, reduce resource waste, and mitigate environmental pollution, variable spraying technologies for aviation applications remain a hot research topic. While the industry currently focuses on varying spray flow, the effect of flow changes on droplet size remains largely overlooked.
In reality, integrating variable spraying with variable droplet size spraying to uncover their intrinsic relationship and developing a precise, controllable variable droplet size spraying system is the path forward for solving precision application issues.
At present, Feifei’s P20 ultra-low-volume high-speed centrifugal atomizing nozzle represents a significant advancement in variable spraying technology. It can atomize pesticides into droplets below 100 μm and precisely adjust spray volume, speed, and width according to wind speed and flight velocity.
Particularly noteworthy is the P20 centrifugal nozzle’s ability to continuously adjust droplet size from 90 to 120 μm. This allows for precise droplet size control to meet the operational demands of different crop pests and diseases, ensuring excellent pesticide application outcomes. Achieving dual-precision control over both spray flow and droplet size marks a major breakthrough in aerospace application technology.
In conclusion, we’ve explored the influence of droplet size on pesticide control outcomes. For contact-action pesticides, smaller droplets provide better control. Different pests require different optimal droplet size ranges, placing higher demands on droplet size precision and variability.
In today’s plant protection drone market, variable spray systems utilizing centrifugal nozzles are gaining popularity. Continuous improvements in dual-precision control over spray flow and droplet size will undoubtedly shape the future of agricultural aviation precision application technology.
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