AHW9Unharvested cereal headland

What it actually is

You grow a spring cereal round the outside of a field and then do not harvest it. The strips are sown at a reduced seed rate, they are no more than around 24 metres wide, and they stand through the summer, the autumn and the winter.

GOV.UK's stated aim is an open-structured spring cereal crop growing in strips or plots on the outer edges of the land parcel, which remains unharvested during the summer, autumn and winter months. The page sets that in the context of a summer food source for farmland birds and insects, helping establish a range of arable plants and other broad-leaved plants, and a habitat present over the winter with food for seed-eating farmland birds.

You manage the strips for long enough to achieve that aim, which GOV.UK says will usually mean keeping them until around mid-February in the year after establishment.

Source: GOV.UK, AHW9 action page, checked 04/08/2026.

What it pays, and what that comes to

The rate is in the panel at the top of this page. Multiplied out:

Source: arithmetic on the payment rate shown at the top of this page, which comes from Tilth's copy of the GOV.UK action catalogue and carries its own last-checked date. The 2 hectares is an illustration.

A hectare of strip at the full 24 metre width is about 417 metres of headland. So the two hectares above is roughly 833 metres of field edge at full width, or about 1,667 metres at 12 metres wide.

Source: arithmetic on the maximum width given on the GOV.UK action page, checked 04/08/2026.

Is it worth it on your ground?

Step one: what it costs to put in. A cultivation and drilling pass and spring cereal seed at a reduced rate. We have not found a published seed price we would put on a page about money, so we are not going to invent one, and cultivation and drilling are your own costs. What matters is that this is not a nil cost action: you spend on establishment and you take nothing off the field.

Step two: what the ground would otherwise return. Gross margins per hectare for England, non-organic, in the 2023/24 crop year. Variable costs have already been taken off these figures, so there is nothing further to deduct.

Source: Farm Business Survey, Crop Production in England 2023/24, Rural Business Research, England, non-organic, 2023/24 column, checked 02/08/2026. The winter wheat figures come from a sample of 572 farms.

The agreement runs three years, so the comparison has to run three years too, and that ground will not be in wheat for all three of them. Three rotations, worked from the crop figures above:

Source: arithmetic on the crop gross margins in step two, from the Farm Business Survey, Crop Production in England 2023/24, checked 02/08/2026. These three are illustrations. Work your own out from the same crop figures.

Step three: the gap, which on this action runs the other way.

Source: the payment rate at the top of this page set against the rotation averages in step two. The figures are subtraction. Seed and establishment are not in them.

The rotation figures already have their variable costs taken off. The payment above does not, so the seed and the establishment pass still have to come out of it. That turns the whole question into one line: does your reduced-rate seed plus your cultivation and drilling come to more than £236 a hectare? Price your own, because that is the only number that decides it.

Three things to set against those figures. What follows is Tilth's own reading rather than scheme guidance.

The survey reports one winter wheat figure, not first and second wheat separately. A rotation with two wheats in it carries a second wheat at the same gross margin as the first, which is unlikely to be how it turns out on your ground. We have not found a published split to cite, so we have not applied a discount of our own invention. Read the rotation averages as the generous end for the crop.

It is one year, and not a strong one. The same report's 2022/23 column put winter wheat's gross margin at £1,570 a hectare against the £988 above for 2023/24. A three-year decision resting on a single crop year is a shaky thing, and this particular year was the lower of the two. Against that stronger year the gaps above narrow sharply and on wheat they close.

A headland is not the field. The gross margins above are field averages. The outer edges are where the shading is, where the hedge takes the moisture, where the compaction from every turn ends up and where the yield map goes pale. This action is confined to those outer edges by its own requirements, so the ground it is compared against is systematically the poorer part of the field.

Where that leaves it. The payment is ahead of all three rotations before establishment, and the ground it goes on is the ground that returns least. If the money were the whole story this would be an easy decision, so the sensible next question is what stops it, and the answer is not price. It is that the area available is fixed by how much field edge you have rather than by how many hectares you farm, that the 25 per cent limited area cap is shared with the other nine actions on that list, and that a standing unharvested crop has consequences for the ground under it. Those are below.

Does it work, and what makes it work better

This section is what we have found in published sources about the practice this action pays for. It is not scheme guidance, it is not Defra's or the RPA's view, and it adds no requirement beyond what the GOV.UK action page sets out. We have named every source and given the date we checked it. What it means for your ground is your decision.

The headline on this action is different from every other page on this site, so it goes first.

Conservation Evidence, based at the Department of Zoology at the University of Cambridge, summarises the published studies behind individual conservation actions and has independent subject experts score each one. Their Farmland Conservation synopsis carries an action called Leave unharvested cereal headlands in arable fields, which is this practice under a different name. It is listed as No evidence found, with no assessment made, on zero studies.

That means something particular and it is worth being exact about it. It does not mean the practice was tested and failed. It means their search of the literature turned up no study of it that met their criteria, so their experts had nothing to score. An action with no evidence behind it and an action shown not to work look nothing alike, and this is the first of those.

Source: Conservation Evidence, Farmland Conservation synopsis, related actions listing on action 651, checked 06/08/2026. Cite as Dicks et al. (2020), Farmland Conservation, pages 283 to 321, in What Works in Conservation 2020, Open Book Publishers.

What we have not found. Nothing measuring AHW9 itself, which is the ordinary case on these pages. But also nothing measuring the practice at all: no figure for what a standing unharvested headland returns in birds, insects or arable plants, and nothing costing it. There is a neighbouring action on the same site, Leave headlands in fields unsprayed (conservation headlands), at https://www.conservationevidence.com/actions/652, which is assessed separately. We have not read it, because Conservation Evidence's site refuses our tools and the page has to be printed by hand, so we are not going to tell you what is on it. It is also a different practice, an unsprayed headland that still gets harvested, so it would not settle this action either way. It is there if you want to go further than this page.

So what follows is advisory guidance from named organisations rather than trial results, and we have said which is which.

What the sources say makes it work better.

Start with the seed rate, because it is the one thing the action asks you to judge and gives you no number for. Farm Wildlife, a partnership of wildlife organisations publishing farm management advice in one place, advise sowing wheat, barley, triticale, oats or rye between February and April at 50 to 100 kilogrammes a hectare, which is lower than a normal crop, so that the crop is not too dense and leaves open habitat for broad-leaved plants to come up through it. They put the width at 6 to 24 metre strips or at the field scale.

On where to put it, Farm Wildlife advise light soils that do not carry high levels of competitive weeds, and siting the headland near tussocky grass margins or hedges to get the most out of it for beneficial insects. The Scottish Government's own guidance for its unharvested conservation headland option, which is a different country's scheme and not this one, says much the same and adds two things: avoid shaded margins such as those next to woodland, and in corn bunting areas a width greater than 10 metres may provide nesting habitat as well as feeding. It also names beetle banks alongside tussocky grass and hedges as the neighbours worth having.

On fertiliser and weeds, Farm Wildlife advise leaving fertiliser off, to cut the risk of competitive grasses and cleavers taking over. The Scottish guidance puts it the same way and adds that the location should be rotated to stop problem weeds building up. It also says to pick fields with lighter soils where there are no problem weed species to begin with.

On what the habitat is for, Farm Wildlife name grey partridge, linnet, bullfinch, corn bunting, yellowhammer, reed bunting and skylark among the birds, along with arable plants, pollinating insects, small mammals and brown hares, and they describe arable plants as the fastest declining group of plants in the UK. Their reason for preferring the unharvested version over the harvested one is that it leaves a standing crop providing seed-rich habitat right through the winter.

One figure on scale, and it is a whole-farm figure rather than one about a strip. The Scottish guidance cites the Game and Wildlife Conservation Trust for the position that at least 3 per cent of arable habitat needs to provide insect-rich brood-rearing cover to support grey partridge recovery. That is a statement about how much of a farm needs to be in cover of this sort, not a measure of what any one headland does, and we have not read the underlying work.

Source: Farm Wildlife, conservation headlands page, checked 11/08/2026. Scottish Government, Rural Payments and Services, supporting guidance for Unharvested Conservation Headlands for Wildlife under the Agri-Environment Climate Scheme, checked 11/08/2026, which is Scotland's scheme and not SFI26.

What follows is Tilth's own reading of how those findings sit against this action, and it adds no requirement beyond what the GOV.UK action page sets out.

The seed rate is the most useful thing on this page and it arrives from an unexpected direction. GOV.UK asks for a rate reduced to a level that can reasonably be expected to achieve the aim and gives no figure at all, which we have flagged further down as a judgement you have to make and write down. Farm Wildlife publish 50 to 100 kilogrammes a hectare for the same practice. That is somebody else's advice rather than a scheme requirement, and the action does not adopt it, but it is a published range from a named source, which is more than the action itself offers. What you drilled and why is still the thing worth recording.

Our reading is that this action is two practices bolted together, and the evidence sits differently on each. One half is a headland where the herbicide programme is cut back to a short list, which leaves broad-leaved plants standing rather than being taken out, and that is the conservation headland idea Farm Wildlife describe. The other half is leaving the crop unharvested so the seed stays in the field over winter. Conservation Evidence assess the first as its own action. On the two together, which is what this action pays for, they have nothing.

The advice to rotate the location, from the Scottish guidance, lands on a choice this action leaves open. AHW9 can be rotational or static. The reason given for rotating is stopping problem weeds building up, which is the same worry as the point further down this page about a standing crop shedding its seed where it stands. Static keeps the habitat in one place across three years, which has its own logic. The published advice we found points one way; the action allows both.

Which leaves the position on this page honest but lopsided. The money case is arithmetic and it stands up. The wildlife case rests on advisory guidance from organisations that work on this rather than on measured results, because the measured results do not exist. If somebody tells you this action is proven to work, they have not looked, and if somebody tells you it is proven not to, they have not looked either.

What you actually have to do

Establish a spring cereal crop, not maize, in strips or plots on the outer edges of the land parcel, not more than around 24 metres wide, sown at a seed rate reduced to a level that can reasonably be expected to achieve the action's aim.

Manage the strips or plots for a period of time that can reasonably be expected to achieve the aim, which GOV.UK says will usually mean keeping them until around mid-February in the year after establishment.

You may undersow a seed mix into the spring cereal crop, and you may use a blend or mix of cereals, provided the aim can still reasonably be expected to be achieved.

Source: GOV.UK, AHW9 action page, checked 04/08/2026.

What you cannot do on it

On the strips or plots: no fertilisers, manures or lime, and no insecticides after around mid-March. The only herbicides permitted are those containing amidosulfuron, clodinafop-propargyl, fenoxaprop-P-ethyl, pinoxaden or tri-allate.

Source: GOV.UK, AHW9 action page, checked 04/08/2026.

Where it can go, and the cap

Arable land used to grow spring cereal crops other than maize, registered as arable land and declared with an arable crop or a leguminous and nitrogen-fixing crop code, along with temporary grassland under TG01 and arable land lying fallow under FA01.

The action is rotational or static, so you can move the strips for the second and third years or keep them in the same place.

Source: GOV.UK, AHW9 action page, checked 04/08/2026.

AHW9 is one of the ten limited area actions under SFI26. The rule is that the total eligible area you enter into them must not be more than 25 per cent of the total agricultural area of your farm. The other nine are CIPM2, CAHL1, CAHL2, CAHL3, CIGL1, CIGL2, WBD3, AHW7 and AHW11. How the 25 per cent limit works.

Source: GOV.UK, SFI26 scheme rules and guidance, section 4.5, checked 23/08/2026.

Things worth watching

This section is Tilth's own reading of where this action is easy to get wrong. It is not scheme guidance, it is not sourced from Defra or the RPA, and none of it adds a requirement beyond what the GOV.UK action page sets out.

Your perimeter decides the area, not your acreage. At around 24 metres, a hectare of strip needs about 417 metres of field edge. A farm of large square fields has less edge per hectare than a farm of small awkward ones, so the same total area gives two farms very different amounts of headland to work with. Work out what you actually have from the boundaries before deciding how much to enter.

The reduced seed rate is a judgement, not a number. GOV.UK asks for a rate reduced to a level that can reasonably be expected to achieve the aim, and gives no figure. Nobody else is going to write that decision down for you, so write down what rate you drilled and why.

A crop left standing sheds its seed where it stands. Every grain that would have gone in the trailer goes on the ground instead, along with whatever else has grown in an open crop that has had no insecticide since March and a very short herbicide list. What that means for the following crop on that ground is a question about your own weed burden rather than about the scheme, and it is worth asking before the strip is drilled rather than after it is cultivated in.

The herbicide list is five actives and nothing else. Check it against the programme you would ordinarily run on a spring cereal before you commit ground, not in the spring when a problem has already appeared.

Rotational or static, and the choice has consequences. If you move it, you repeat the siting and the seed rate decision three times against three different cropping plans. If you leave it, the same field edge carries a standing crop and its seed return for three years running.

Mid-February is the usual case, not a deadline. GOV.UK gives the period as long enough to achieve the aim and says it will usually mean around mid-February in the year after establishment. That is more room than a fixed date, and it also means there is nothing to point at afterwards except what you actually did and when.

The 25 per cent cap is shared, not per action. AHW9 draws on the same allowance as CAHL2 winter bird food and AHW7 enhanced overwinter stubble, which are the two most likely to be sitting beside it in an arable application. Total them together before the form is filled in rather than deciding them separately.

If the parcel is an SSSI, or has historic or archaeological features on it, read the eligible land section of the action page against your own parcels. There are extra steps in that part of the page that do not apply to ordinary arable ground, and they are easier to deal with before an application than during one.

Keeping the evidence

Also Tilth's own reading. GOV.UK sets the requirements; what follows is a practical suggestion about record keeping.

GOV.UK gives field operations at land parcel level with their associated invoices, and photographs or other documentation, as its examples of evidence of what you have done.

This action is unusual in that it produces a proper paper trail on the way in and almost none on the way out. There is a seed invoice and a drilling operation, and then there is nothing, because the harvest that would normally close the record never happens. What that suggests to us is that the records worth making are the drilling date with the seed rate against it, the position and width of the strips, and dated photographs through the summer and the winter. A standing crop in August and the same strip in January look nothing alike, and between them they show the action doing the thing it is paid for.

Tilth lets you draw the strip against the field boundary you already have, and holds the drilling record, the seed rate and the photographs against that same strip.

The part only your own ground can answer

The arithmetic above says this action pays, and it says so before establishment costs. Two things decide whether that holds on your farm, and neither is in a national survey. The first is how much field edge you actually have, because that sets the ceiling on the area regardless of what the money says. The second is what those particular headlands return when you crop them, because a headland that yields like the field middle is a different decision from one that has been losing you money for years. Tilth holds your boundaries and your yield history in the same place, so both questions have the same answer sheet. Request an invite.