Using spot spraying and drone mapping to spend less, and the funding that has just made both of them pay
- Jack Harris
- 1 day ago
- 8 min read
The SFI26 application window opens in September. Here is what precision application actually does on a farm — and what changes when the scheme starts paying you to do it.
Most farms I visit are already convinced of the principle.
Nobody wants to put chemical on bare ground, or spread the same rate of nitrogen across a field that clearly isn't the same field from one end to the other.
The question has never been whether precision application works. It's whether it pays for itself quickly enough.
For the last few years, that has been a genuinely close call.
From September, it isn't.
Before we get to the funding, though, it's worth being straight about what this kit does when you take the subsidy out of it entirely.
If it only works because of a scheme, it isn't worth buying — schemes change. So let's start there.
Part one: what the kit does before anyone pays you a penny spot spraying
Spot spraying: stop spraying bare ground
A conventional sprayer applies herbicide evenly across a field, whether or not there is anything there to kill. On a stale seedbed, a stubble with a scatter of green, or a wide-row crop, most of what goes through the nozzles lands on soil.
The Carbon Bee Smart Striker X changes that.
Cameras along the boom look at the ground ahead of the nozzles and decide, in real time, whether there is a weed.
Where there is, the nozzle opens. Where there isn't, it stays shut. The cameras combine RGB imaging with hyperspectral data to identify a weed from a crop plant rather than simply green from brown.
Two modes, two jobs:
Green on brown handles stale seedbeds, stubble, and pre-harvest work. Everything green is a target, and the saving is simply the proportion of the field that isn't green.
Green on green handles weeds inside a growing crop, where the system has to distinguish the weed from the plant you are trying to keep.
Customers, on average, depending on weed pressure, save between 60-70% over their sprayed areas; this can go up to 90% in some fields! Water and the costs that go with them also are reduced. To see some scenarios using your own farm data, try our savings calculator here.
The cameras retrofit to the sprayer you already own — trailed or self-propelled. We survey the machine, install, calibrate in the field, and stay on the end of the phone afterwards. No new sprayer, no trade-in.
MRLs in crops are becoming more prevalent, and spot spraying helps reduce the risks of MRLS being present or detected; reducing applications of chemicals on crops has also been shown to improve yields in some cases. Even if a chemical is safe for a crop, the crop still has to ingest it and get rid of it. All of which takes energy away from growing.
To find out more, get in touch by emailing info@fieldcrfat-tech.co.uk
Variable rate: stop averaging a field that isn't average
The other half of the same idea. A flat rate of nitrogen across a field treats the headland, the light patch and the best ground as if they were the same. They aren't, and you already know they aren't — you can see it from the cab every year.
CultiWise turns that knowledge into a file the spreader can read. We fly the field with RTK-level multispectral drones and map the Red Edge index, which tracks chlorophyll and plant health, and we pull multi-year satellite history alongside it so you're looking at how the field behaves over time rather than on one particular Tuesday. You pick the strategy and the range of rates. We build the maps and the files.
The whole thing runs in a browser — nothing to install — and maps are usually processed and back with you within 24 hours. Files are output in formats that work with most sprayers, spreaders and controllers on the market.
The benefit is the same as spot spraying: you stop spending money in the places where it doesn't do anything. On thin crop, you're no longer spending money on yield that isn't going to arrive; on strong ground, you're no longer capping a crop that could have done more. And the environmental side follows without you having to try — less nitrogen going on where the crop can't use it is less nitrogen finding its way somewhere it shouldn't.
Try an area for free here.
Part two: now add SFI
Here is where it gets interesting, and here is also where you want to be careful, because a lot of what is being said about SFI this autumn is loose.
SFI does not buy the precision equipment we sell.
It never has. The scheme that bought equipment was the Farming Equipment and Technology Fund, and FETF 2026 has closed.
What SFI does is pay you, per hectare per year, for farming in a particular way.
And in SFI26 there are two actions that describe precision application so precisely they read like a specification sheet.
PRF2 — camera- or remote sensor guided herbicide spraying
£43 per hectare, per year, for three years.
The requirement is that you apply systemic herbicides using "camera or remote sensing technology that identifies specific weeds to be controlled" and which "automatically switches on individual nozzles to apply the herbicides directly to the identified weeds."
That is a description of what the Smart Striker X does.
One important limit, and we'd rather you heard it from us than found out later. Guidance currently accepts camera recognition for four situations:
docks and nettles in grass, or leys containing clover
all weeds in maize
certain crops grown on wide row spacings, such as potatoes
stubble, where there's green growth
The Carbon Bee Smart Striker X can do all of the above, so if you grow any of the crops listed above, check out our savings calculator to work out potential savings. Then add your earnings for SFI.
Blanket spraying is still permitted for three things — glyphosate to destroy a cover crop or make a stale seedbed, residual pre-emergence herbicides, and pre-harvest desiccant on combinable crops — so entering the action doesn't tie your hands as tightly as people assume. And the action is rotational or static, meaning you can move the land in years two and three or keep it where it is.
PRF1 — variable rate application of nutrients
£27 per hectare, per year, for three years.
Apply your major nutrients using variable rate equipment, and this pays. What makes it directly relevant to us is a single line in the requirements: the variable rate file can be built using data from zonal soil or crop testing "or remote sensing". For nitrogen, it goes further and names "remote sensing of crop reflectance" explicitly.
That is exactly what a CultiWise drone flight produces. This isn't a service that sits near the action — it's a service the action names.
There's a timing condition attached, and it's the one worth planning around: for nitrogen, remote sensing "will usually need to be carried out no more than around 14 days before the application of N."
Which is precisely why we turn flights round in 24 hours or less. A fortnight sounds generous until you factor in weather, ground conditions and the fact that everyone else wants their spreader running the same week.
You'll also need soil data covering at least P, K, Mg and pH, less than five years old, sitting behind the file.
And they stack
This is the part most people miss. Checking the compatibility tables on the PRF1 action page, PRF2 is listed among the actions you can do on the same area of land. They are not alternatives. On ground where both apply, that is £70 per hectare per year, for three years.
What that does to the sums
Take a 250-hectare arable farm with 60 hectares of maize in the rotation, and assume 220 hectares of the cropped area goes into PRF1.
Hectares | Rate | Per year | Over three years | |
PRF1 — variable rate nutrients | 220 | £27/ha | £5,940 | £17,820 |
PRF2 — camera-guided spraying | 60 | £43/ha | £2,580 | £7,740 |
Scheme income | £8,520 | £25,560 |
That is before a single pound of input savings. Now take your own herbicide spend across those 60 hectares of maize and remove up to 70% of it.
Then take whatever variable rate does to your fertiliser bill across 220 hectares — the number depends entirely on how variable your ground is, which is a conversation to have with your agronomist, not a figure for us to invent.
The point isn't the exact total. It's the shape of it. Kit that used to pay back on input savings alone now pays back on input savings plus three years of scheme income, and the payback period moves from "worth thinking about" to "obvious".
For context, SFI26 agreements are capped at £100,000 per agreement year, and you can hold one agreement per farm business.
What we won't tell you
A few things that are true and unhelpful to us, which is exactly why they're worth saying:
SFI pays for the practice, not the machine. You need the equipment on the farm before any of this applies. The scheme improves the return on an investment you make; it doesn't make the investment for you.
The paperwork is real. PRF2 wants "as applied" data — a map showing where individual nozzles switched on — plus a record of any permitted blanket application, and a contractor's invoice if you used one. PRF1 wants the variable rate file that went into the equipment, an "as applied" record at parcel level, and invoices for the soil testing. None of it is onerous, and most of it is generated by the job itself, but it isn't nothing.
Smart Striker X syncs data back to the Hive platform to show exactly where weeds were seen and sprayed.
Not every hectare qualifies for both. The PRF2 situations are narrower than the machine's capability. How much of your farm fits depends on your rotation, and it's worth working that out on paper before you commit to anything.
What to do before September
The window opens in September, and there is no published closing date — it closes when the budget is allocated. Applications are widely expected to be heavily oversubscribed. That means the preparation matters more than the paperwork on the day.
Work out your qualifying area now
Which parcels, which crops, which actions. This is the bit that takes time, and it's the bit you can do today.
Check your RPA details
Land covers and use codes on your digital maps have to be right and compatible with the actions you want. Contact details and agent permissions too.
Get your soil data in order for PRF1
P, K, Mg and pH, less than five years old. If yours is older than that, sampling needs to happen before the file does.
Book a demo
Seeing a machine work in a field settles more questions in twenty minutes than any amount of reading. We can bring one to you.
FieldCraft Technologies has partnered with LH Agro UK to fit a small Carbon Bee system and Capstan PWM system to a buggy to showcase the system on farm.
Get in touch now to book a demo.
Talk to us
We supply, fit and support Carbon Bee spot spraying systems, and we produce variable rate and spot spray mapping through CultiWise. We'll sit down with your cropping plan and work out honestly which hectares qualify for what, what the kit would save you on your own figures, and whether the numbers work on your farm. If they don't, we'll say so.
Demos available. Free CultiWise trial.
Scheme details in this article are taken from the GOV.UK guidance for SFI26 actions PRF1 and PRF2 as published at the end of August 2026. Payment rates and requirements can change — check the current guidance and take scheme advice specific to your business before you apply.
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