On-site operation skills of agricultural drones

Practical Operation Techniques for Agricultural Drones in Field Applications

Understanding Terrain and Environmental Factors Before Flight

Assessing Obstacle Distribution and Field Shape

Before initiating any flight operation, conducting a thorough pre-flight terrain survey is critical. In irregularly shaped fields, such as those with undulating terrain or dense tree lines, manual flight mode offers better control than automated navigation. For example, in cornfields where plant height exceeds 1.5 meters, automated height sensors may struggle to distinguish between crop canopy and ground level, leading to inconsistent spraying patterns. Manual operation allows pilots to adjust altitude dynamically based on real-time visual feedback, ensuring uniform coverage even in complex environments.

Adapting to Wind Conditions and Temperature

Wind speed directly impacts spray drift and deposition accuracy. Studies indicate that wind speeds exceeding 4 meters per second increase off-target deposition by up to 30%, particularly for lightweight pesticide formulations. Operators should prioritize early morning or late afternoon flights when wind velocities typically remain below 3 meters per second. Temperature management is equally important—high temperatures accelerate pesticide volatilization, reducing efficacy. In regions with average daily temperatures above 30°C, scheduling nighttime operations or adding anti-volatilization adjuvants can mitigate this issue.

Optimizing Flight Parameters for Efficient Coverage

Balancing Speed and Spray Volume

The optimal flight speed for most agricultural drones ranges between 3.5–5 meters per second. At speeds below 3.5 m/s, downward airflow from rotors creates excessive turbulence, causing droplets to bounce off leaf surfaces. Conversely, speeds exceeding 5 m/s reduce contact time between droplets and targets, leading to uneven coverage. For liquid formulations requiring 15–20 liters per hectare, maintaining a speed of 4 m/s ensures adequate droplet density while minimizing drift. When handling systemic pesticides, reducing speed by 10–15% enhances absorption rates through prolonged leaf contact.

Adjusting Altitude Based on Crop Architecture

Flight altitude must align with crop growth stage and structural characteristics. During early vegetative stages, maintaining a height of 2–2.5 meters above ground level ensures comprehensive coverage of basal leaves. As crops enter reproductive stages, increasing altitude to 3–3.5 meters accommodates taller stems while preventing rotor wash from damaging delicate flowers or fruits. In vineyards, adopting a “stepped” altitude strategy—lower passes for trellis-trained vines and higher passes for overhanging canopies—improves penetration into dense foliage.

Enhancing Spray Quality Through Technical Adjustments

Selecting and Mixing Adjuvants Properly

Adjuvants play a crucial role in improving spray performance. For example, adding 0.5–1% mineral oil-based adjuvants reduces droplet surface tension, enhancing adhesion to waxy leaf surfaces. In humid environments (>70% RH), incorporating anti-drift polymers extends droplet lifespan by preventing premature evaporation. When mixing multiple adjuvants, follow a specific sequence: first dissolve powdered adjuvants in water, then add liquid adjuvants, and finally incorporate pesticides. This order prevents chemical interactions that could clog nozzles or reduce efficacy.

Managing Nozzle Selection and Maintenance

Nozzle type significantly influences droplet spectrum and distribution uniformity. For broadleaf crops, ceramic flat-fan nozzles produce medium-sized droplets (150–250 microns) ideal for systemic pesticides. In contrast, air-induction nozzles generate larger droplets (300–400 microns) suitable for contact insecticides in windy conditions. Regular maintenance is essential—after every 10 hectares of operation, clean nozzles with soft brushes to remove residue buildup. Avoid using metal tools, which can scratch nozzle surfaces and alter spray patterns.

Ensuring Safety and Compliance During Operations

Implementing Personal Protective Measures

Operators must wear full-body protective gear, including chemical-resistant suits, N95 respirators, and nitrile gloves, when handling pesticides. During mixing and loading operations, maintain a minimum distance of 5 meters from water bodies to prevent contamination. In case of accidental exposure, rinse affected areas with clean water for 15 minutes and seek medical attention immediately. For eye exposure, use emergency eyewash stations if available or improvise with bottled water.

Complying with Regulatory Requirements

Before each flight, verify that the operation area complies with local aviation regulations, including no-fly zones around airports and populated areas. In regions with bee colonies, schedule flights before sunrise or after sunset to minimize exposure to pollinators. Document all operations, including flight paths, pesticide types, and application rates, for regulatory audits. Maintain communication with local agricultural authorities to stay updated on pesticide restrictions and buffer zone requirements.

Post-Flight Maintenance for Longevity

Cleaning and Inspecting Equipment

After completing operations, rinse the spray system with clean water for 3–5 minutes to remove pesticide residues. For stubborn deposits, use a 1% detergent solution followed by thorough rinsing. Inspect the drone frame for chemical corrosion, particularly around battery contacts and motor mounts. Wipe down electronic components with dry cloths to prevent moisture damage. Store equipment in climate-controlled environments (15–25°C) to prolong battery life and prevent material degradation.

Analyzing Flight Data for Continuous Improvement

Most modern drones generate detailed flight logs, including GPS coordinates, altitude variations, and spray volume records. Analyze this data to identify patterns such as uneven coverage areas or excessive battery consumption. For example, if logs show consistent under-spraying in field corners, adjust future flight paths to include overlapping passes. Similarly, high battery drain rates may indicate inefficient route planning, prompting a shift to more linear flight patterns. Regular data review enables incremental improvements in operational efficiency and cost-effectiveness.