Spreading Fertiliser With Agricultural Drones
Learn how drone fertiliser spreading works: choose tanks/discs, plan A–B routes, set rates and height, monitor coverage, and verify crop results.
What drone fertiliser spreading covers
Agricultural drones can do more than spray liquids. A spreading tank and spinning disc let them broadcast rice seed, granular fertiliser and other solid farm inputs.
- DJI Agras T100 100 L
- DJI Agras T70P 70 L
- DJI Agras T55 50 L
- DJI Agras T50 40 L
- DJI Agras T25 20 L
- DJI Agras T25P 20 L
| Model | Value |
|---|---|
| DJI Agras T100 | 100 L |
| DJI Agras T70P | 70 L |
| DJI Agras T55 | 50 L |
| DJI Agras T50 | 40 L |
| DJI Agras T25 | 20 L |
| DJI Agras T25P | 20 L |
Sources: ag.dji.com, ag.dji.com, ag.dji.com, ag.dji.com, ag.dji.com, ag.dji.com
The main aim is fast, even coverage without driving through the crop. Accurate routes can cut gaps and overlap, while aerial work avoids wheel damage. Drones can also reach remote ground and fields that are too wet for tractors.
The value lies in control rather than flight alone. Operators can set the route, flight height, speed, spread width and output to suit the field. Flight records and live monitoring then show how the job progressed.
This makes spreading useful for direct rice seeding as well as crop feeding. The same broad workflow applies to both: check the field, set the target, plan the route, verify output and review the result.
Choosing the right spreading approach
Archived DJI research describes an older spreading system that replaced the tank fitted to its farm aircraft. It was intended for seed, fertiliser, solid chemicals and fodder. The key operational point remains relevant: spreading needs the correct tank and spreader, not the liquid spray set-up.
Current aircraft offer a wide range of spreading tank sizes. The DJI Agras T25P has a 30 L spreading tank, while the DJI Agras T25 has a 35 L tank. The DJI Agras T50 has a 75 L spreading tank, and the DJI Agras T55 has an 80 L DS80L spreading system.
For larger loads, the DJI Agras T70P has a 100 L spreading tank. The DJI Agras T100 has a 150 L spreading tank with a maximum load of 100 kg. Operators can compare these and other verified drone specifications before matching an aircraft to the work.
Tank size is only one part of that choice. The operator must also consider the field, target rate, crop stage and access to the loading point. A large tank may reduce refill stops, but the route and spread settings still decide coverage quality.
The older direct-seeding research also showed why settings cannot be treated as fixed for every job. Hopper outlet size and spinning-disc speed could be changed case by case. Saved job settings could then guide later work or another operator.
Rice spreading and fertilisation checklist
Rice work starts with crop timing, not the aircraft. The relevant stages include vegetative growth, flowering and ripening. Seed and fertiliser jobs should fit the crop stage, local climate and advice from an agronomist.
The target input also matters. Rice nutrition may call for nitrogen, phosphorus or potassium fertiliser at different stages. Applying too much can harm the soil and wider environment, so the rate should follow the crop need.
Before starting, use a clear field checklist:
- Confirm that the seed or granular fertiliser suits the planned spreading job.
- Inspect the field and identify people, buildings and other obstacles.
- Map the field boundary and plan routes that cover the full treatment area.
- Set height and speed for the crop and ground conditions.
- Set the application rate, route spacing, spinner speed and hopper gate.
- Turn obstacle avoidance on where the set-up supports it.
- Monitor the job for gaps, overlap and changes in field conditions.
- Save the settings and job record for review.
Route planning is central to even work. Each pass must link with the next without leaving untreated strips or placing too much material in an overlap zone. This is especially important when applying fertiliser to an established crop.
Height also needs care. Lower flight can improve spreading accuracy, but it reduces clearance over crops and uneven ground. The operator should use field conditions and crop height when setting the route.
DJI’s broader rice guidance gives a separate set of recommended seed-spreading settings. It lists a height above the crop of 4–5 m, a speed of 6–7 m/s and route spacing of 4.5–5.5 m. The listed application rate is 140–200 kg/ha, with spinner speed at 900–1100 rpm/min and wind below 5 m/s.
Those figures are guidance for the stated rice-seed task, not universal fertiliser settings. Product form, crop need and field state still have to match the job plan. Operators should not copy a saved profile simply because the crop name is the same.
Live monitoring helps the operator spot a route or coverage problem while work is under way. The saved data is useful after the flight as well. It provides a record for comparing settings with emergence, crop colour and later growth.
Field setup and route planning from a direct rice seeding test
DJI’s direct rice seeding test gives a useful example of how field state shapes the plan. The field needed to be flat, with mud settled at the bottom and water left on the surface. That preparation gave the seed a more consistent receiving surface.
The test used A–B Route Operation Mode. Flight speed was 1.2 m/s, altitude was 1.5 m and spreading space was 2.5 m. These figures describe that test and should not be mixed with the later general rice guidance.
The example also used a spinner-disc speed of 520 rpm and a hopper outlet size of 60%. Both settings could be changed to suit the job. This is a sound reason to record the full set-up rather than noting the flight route alone.
The field was split into groups with different seed quantities. DJI reported that saved spreading settings could help with later use or guide another operator. That turns a field test into a repeatable work record.
For an operator, the main lesson is not to copy one value in isolation. Speed, height, spacing, disc speed and hopper opening work as a set. Changing one part may change where the material lands and how much reaches each part of the field.
Ground and water state are part of that set as well. A route built for a flat paddy should not be assumed to suit uneven land. The field inspection must come before the route is approved.
What the wheat fertiliser test shows about uniformity
A DJI wheat trial compared drone spreading with manual fertiliser spreading on fields of equal size. Each field covered 0.174 hectares. The crop needed nitrogen-based fertiliser during the heading phase, with a target use of 300 kg/ha.
Manual spreading used five workers and took 20 minutes. The drone operation took about two minutes after the pilot set the flight path and job parameters. This was a controlled comparison, not a blanket work-rate claim for all fields.
Uniformity was the more important result. Images taken 30 days after fertilising showed that uneven input had affected crop growth. Some wheat matured late after receiving too much nitrogen-based fertiliser.
The drone-treated plot showed more even and healthier growth in the reported trial. That outcome links route control and output control to crop response. Fast work has little value if material is not spread evenly.
Operators should therefore judge a job by more than total area and elapsed time. The review should ask whether the route covered the field, whether overlap occurred and whether crop growth stayed even. Follow-up field checks help connect the flight record with the actual result.
Working in mud and narrow treatment windows
Wet soil can stop tractors while the crop still needs treatment. Research from rice farms describes tractor delays of up to fifteen days when fields remained muddy. Such a wait can push work beyond the required treatment window.
Aerial spreading avoids placing heavy machinery in the field. It can also prevent wheel damage to seedlings and removes the need to walk through deep mud with a hand spreader. This makes drone work a practical option when access, rather than field size, is the main problem.
Traditional work can also damage crops where passes overlap. One rice grower reported burnt or damaged areas after overlapping treatments, while heavy machinery crushed seedlings. A planned aerial route aims to reduce both overlap and physical contact with the crop.
Contractors should inspect access around the field as well as conditions inside it. The loading point, take-off area and route must keep the aircraft clear of people, buildings and obstacles. A field that is inaccessible to a tractor may still need careful ground planning for the drone team.
The weather remains part of the decision. DJI’s rice guidance sets wind below 5 m/s for the stated seed-spreading task. Operators should also account for local climate and current field conditions when choosing the work window.
Cleaning and checks after spreading
The cleaned area should then be wiped with a damp cloth and dried with a dry cloth.
This supports safe flight and consistent output on the next job. More operator-focused material is available through the guides index.
Saved settings do not replace these checks. A clean spreader and sound aircraft are the base for repeatable work. The next field still needs its own inspection and route review.
Building precision agriculture decisions around spreading
Precision agriculture treats parts of the same field in different ways. Instead of using one field-wide average, the grower can make finer choices about where seed, fertiliser or crop treatment is needed.
Drone data can support that process by showing field condition and crop growth. A spreading plan can then target selected parts of the field rather than treating every area as identical. This links observation, planning and input use.
The workflow should remain simple. Inspect or map the crop, identify the areas that need treatment, set the spreading plan and save the job record. Then check the crop response and use that evidence when planning later work.
Precision does not mean choosing the most complex setting. It means applying the right input to the right part of the field with as little gap and overlap as possible. For drone fertiliser spreading, disciplined field setup and route control matter more than headline speed.