Why Spraying Tall Crops Is a Problem for Ground Machinery
Every farmer growing corn, sunflower or rapeseed knows the situation: the crops are already tall, they need treatment against pests or diseases, but entering with a tractor means destroyed plants. Ground sprayers cut strips of crushed stalks – the so-called "trampling paths" – leading to 3–5% harvest loss with every pass.
With corn reaching 1.5–2 m in height, the tractor wheels and sprayer boom break stalks and tear leaf mass. With sunflower above 80 cm the situation is analogous – every trampling means dozens of decares of lost production. In the Dobrudzha and Thracian Plain regions, where parcels are large, losses are measured in thousands of lev per season.
Besides direct losses from crushed plants, trampling compacts the soil in tyre tracks, which worsens the water-air regime and reduces yield in the following year. With repeated passes (for example with combined herbicide and fungicide treatment) tractor paths cover up to 8–10% of the field area.
This is precisely where tall crops drone spraying solves the problem completely – without crop contact, without trampling, without losses.
How the Drone Sprays Tall Plants
The agricultural drone flies at 2–3 metres above plant tops and applies the preparation from the top downwards. The key to effective coverage is Vortex technology – the powerful propeller flows generated by the drone rotors create a downward air current that literally pushes the fine droplets into the leaf mass.
This effect provides:
- Uniform coverage of the upper and lower leaf surface
- Preparation penetration to the lower tiers of the plant
- Minimal drift (wind carry) thanks to the directed flow
Unlike ground sprayers, the drone does not touch a single stalk. The result is 100% preserved crop and full treatment – even with corn above 2 metres or sunflower in full bloom.
Which Crops and at What Stage Need a Drone?
Corn – Above 1 m
Corn grows fast and already at the 6–8 leaf stage (BBCH 16–18) reaches a height where the tractor starts causing damage. In the tasselling phase (BBCH 51–59) ground treatment is practically impossible without significant losses.
Typical drone treatments for corn:
- Herbicide spraying at the 4–8 leaf stage – see details on herbicide spraying of corn
- Fungicide treatment before and during tasselling
- Insecticide spraying against European corn borer
- Foliar feeding with microelements
More about the full cycle of corn drone spraying.
Sunflower – Above 80 cm
Sunflower is especially vulnerable to trampling, as its stalks break easily. After stage BBCH 30 (above 80 cm) treatment with ground machinery carries serious risk. Fungicide protection against white rot (Sclerotinia) is critical precisely at the start of flowering – a period when sunflower is already over 1.2 m tall.
With a drone we cover:
- Fungicide spraying at early flowering (BBCH 61–65)
- Insecticide treatment against sunflower moth
- Desiccation before harvest
Learn more about sunflower drone spraying.
Rapeseed – At Flowering Stage
Rapeseed reaches 1–1.5 m during flowering and is extremely sensitive to mechanical damage in this period. Fungicide treatment against Sclerotinia and Alternaria is mandatory precisely when the tractor can no longer enter without losses. Every ground machinery pass through flowering rapeseed knocks off flowers and reduces the number of pods – losses reach up to 7–8% in the path of entry. The drone enables timely fungicide protection without a single lost flower.
Other Tall Crops
Tall crops drone spraying is also applicable for:
- High-trained vineyards – drone sprays from above without damaging the vine shoots
- Orchards – effective crown coverage
- Tall vegetable crops – staked tomatoes, late-stage peppers
DJI Agras T50 – the Drone for Tall Crops
At AirAgro we use the DJI Agras T50 – the leading agricultural drone on the market. Here is why it is ideal for tall crops:
| Characteristic | Value | | --------------- | ------------------------------ | | Tank | 40 litres | | Working width | 6–7.5 m effective strip | | Productivity | up to 200 dka/hour | | Flight height | adjustable, 2–3 m above crop | | Navigation | RTK accuracy ±2 cm | | Spraying system | 8 nozzles with adjustable flow |
The T50 has a distance-measuring radar to the crop, meaning it automatically adapts its height to the terrain and plant height. Thus coverage remains uniform even on uneven relief – a common situation in the areas around Plovdiv and Stara Zagora.
The Vortex technology of the T50 generates an airflow at speeds up to 8 m/s, guaranteeing preparation penetration even into dense corn above 2 metres.
When to Order Drone Spraying – Seasonal Calendar
| Period | Crop | Treatment | | ------------------ | --------------------- | ------------------------------- | | April – May | Rapeseed (flowering) | Fungicide, insecticide | | May – June | Corn (4–8 leaf) | Herbicide, foliar fertilization | | June – July | Corn (tasselling) | Fungicide, insecticide | | July | Sunflower (flowering) | Fungicide against Sclerotinia | | August – September | Sunflower / Corn | Desiccation |
The critical windows are short – sometimes 5–7 days. With productivity of up to 200 decares per hour, the drone enables timely response without waiting for machinery or risking delay.
We recommend planning treatments in advance – contact the AirAgro team at least 5–7 days before the expected date. In peak months (June–July) the schedule fills up quickly, and early booking guarantees that spraying will be performed within the optimal agronomic window.
Comparison: Drone vs Tractor for Tall Crops
| Parameter | Tractor | Drone | | --------------------- | --------------------- | ------------------ | | Crop trampling | 3–5% losses | 0% losses | | Access with tall crop | Limited (above 1 m) | Unrestricted | | Work on wet terrain | Risky – getting stuck | No problem | | Speed | 80–120 dka/hour | up to 200 dka/hour | | Water per decare | 20–30 L | 1–2 L |
For a full comparison between the two methods see our article: Drone or tractor for spraying – which is more economical?
Where We Offer Tall Crops Drone Spraying
AirAgro serves agricultural farms across Southern and Northeastern Bulgaria:
- Plovdiv and Plovdiv region – Maritsa, Rakovski, Kaloyanovo
- Stara Zagora – Kazanlak Plain, Chirpan
- Pazardzhik – Pazardzhik Plain, Septemvri, Belovo
- Haskovo – Haskovo and Harmanli lowlands
- Dobrudzha – General Toshevo, Dobrich, Silistra
- Thracian Plain – from Pazardzhik to Svilengrad
Our operators are certified by BFSA (Bulgarian Food Safety Agency) for work with plant protection products. Every treatment is documented with a GPS log and coverage report.
Frequently Asked Questions
Can the drone spray corn taller than 2 metres?
Yes. The DJI Agras T50 flies at a set height above the crop (usually 2–3 m) and uses radar for automatic terrain following. The Vortex flow ensures preparation penetration even in very dense and tall corn.
How many decares per hour does the drone cover with tall crops?
At standard spraying mode (1–2 L/dka) the drone covers 150–200 decares per hour. With tall crops speed may be slightly reduced for better coverage, but remains significantly higher than ground machinery.
Is drone treatment safe for bees and the environment?
The drone sprays with ultra-fine droplets and a directed flow, minimising drift (carry of preparation). Treatments are performed early in the morning or in the evening when bees are not flying. We observe all BFSA requirements for buffer zones.
What preparations can be applied with a drone?
The drone applies all herbicides, fungicides, insecticides and foliar fertilizers registered for aerial application. AirAgro works only with products approved by BFSA for plant protection.
Book Drone Spraying for Your Tall Crops
Do not wait for crops to grow tall and find yourself without the possibility of treatment. With tall crops drone spraying from AirAgro you save harvest, time and costs. Our clients in Plovdiv, Stara Zagora and Dobrudzha already benefit from zero trampling losses and fast treatment execution – even in the height of season.
Contact us:
Call today for a free consultation and offer for your areas in Plovdiv, Stara Zagora, Pazardzhik, Haskovo, Dobrudzha and the entire Thracian Plain.
