AHW7Enhanced overwinter stubble

Two GOV.UK pages say different things about the scheme

The standalone GOV.UK page for AHW7 sits under "Sustainable Farming Incentive (SFI) scheme: expanded offer for 2024" and was last updated on 27/03/2025. The GOV.UK SFI26 actions publication lists AHW7, enhanced overwinter stubble, among the farmland wildlife actions for arable and horticultural land, headed "updated for SFI26". The SFI26 scheme rules and guidance also name AHW7 in the list of limited area actions.

Source: scheme heading and last-updated date, GOV.UK AHW7 action page, checked 02/08/2026. AHW7's listing under SFI26, GOV.UK, SFI26 actions, and GOV.UK, SFI26 scheme rules and guidance, section 4.5, both checked 02/08/2026.

What follows is Tilth's own reading of those page details. It is not scheme guidance, it is not sourced from Defra or the RPA, and it adds no requirement beyond what the GOV.UK action pages set out.

If you arrive at the AHW7 action page from a search, the 2024 heading on it can read as though the action has been left behind. The SFI26 documents do not read that way. The practical point is that the action page is where the requirements are set out in full, and the SFI26 documents are where the cap below comes from, so it is worth having both open rather than either one alone.

What it actually is

You take a cereal, oilseed rape or linseed crop off, and then you leave the ground alone. GOV.UK's stated aim is that there is a post-harvest stubble remaining during the autumn, winter, spring and summer months. The page sets that in the context of providing a winter food source for seed-eating farmland birds, and foraging and nesting habitat for farmland birds during the spring and summer months.

The stubble stays until around mid-summer the following year, and you must not apply a pre-harvest desiccant to the crop that produced it.

Source: GOV.UK, AHW7 action page, checked 02/08/2026.

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 6 hectares is an illustration.

Is it worth it on your ground?

Step one: what it costs to put in. Nothing. There is no seed, no input and no establishment operation, so the payment stands at its full value with nothing deducted from it. That makes this the simplest money question of any action on the site, and the only one where step one is a single word.

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.

Source: the payment rate at the top of this page set against the rotation averages in step two. The remaining figures are subtraction.

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.

What you are not spending is not in the table either. A gross margin has the variable costs taken out of it, but it does not have your establishment pass, your autumn fuel or your management time in it. On a stubble there is none of that to spend. Where that lands for you depends on your own costings, and it moves the gap in the action's favour rather than against it.

Where that leaves it. Against a rotation performing at national averages the crop is ahead by something in the region of £175 to £247 a hectare a year, which is the narrowest gap of any action on this site that takes ground out of production. Two things close it further, and neither is a number we can put in the table for you. The first is a field that returns below your own rotation average, which is the usual case for taking ground out. The second is the herbicide exception below, because on heavy ground with a grass weed problem, a year without a crop and a permitted spring graminicide is doing something other than feeding birds. What that is worth depends entirely on what your problem is and what you would otherwise do about it, and we have not found a published figure for it that we would put on a page about money.

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.

None of the work below is about AHW7 by name. It is about leaving crop stubbles standing over winter, and this action is one way of paying for that practice. One difference is worth holding onto while you read it. The practice that was assessed is defined as leaving stubbles until at least February or March. AHW7 runs to around mid-summer, so the action asks for a longer stubble than most of the studies were measuring.

The graded assessment. 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. Leaving overwinter stubbles comes out in their category Likely to be beneficial, on 20 studies. The expert scores behind that are 90 per cent for effectiveness, 50 per cent for certainty, and harms not assessed. Those two are not the same thing. Effectiveness scores only the size and direction of the effects that were reported, and certainty is the separate score for how many studies there are, how well built they are, and how much ground they cover. A high effectiveness score sitting next to a middling certainty score means the reported effects were large and the panel was less sure they carry across everywhere.

Source: Conservation Evidence, action 695, Leave overwinter stubbles, in the Farmland Conservation synopsis, checked 05/08/2026. Cite as Dicks et al. (2020), Farmland Conservation, pages 283 to 321 in What Works in Conservation 2020, Open Book Publishers.

What the studies found, both ways. Eighteen studies investigated the effects. Thirteen, from Finland, Switzerland and the UK, found evidence of some benefit to plants, insects, spiders, mammals or farmland birds, including higher densities of farmland birds in winter, increased grey partridge productivity, and increased cirl bunting numbers and territory density where stubbles were one of a group of conservation measures applied together. One replicated site comparison from the UK found inconsistent or no effects on farmland bird numbers. Three studies found only certain species responded: two found only skylark, or only skylark and linnet, out of 23 and 12 farmland bird species tested; one found only grey partridge and tree sparrow. Two UK studies found different bird species benefited from different stubble heights.

Source: Conservation Evidence, action 695, key messages, checked 05/08/2026.

At the strong end, a 2007 systematic review by Roberts and Pullin pulled together five papers from experiments run between 1992 and 2002 and found significantly higher densities of farmland birds in winter on fields with stubbles than on conventionally managed fields, seed-eating songbirds and crows in particular. A 2000 literature review by Aebischer and others recorded the UK cirl bunting population rising from between 118 and 132 pairs in 1989 to 453 pairs in 1998, with numbers on scheme fields up 70 per cent against a 2 per cent rise on neighbouring non-scheme land. Those schemes provided stubbles, grass margins, managed hedges and set-aside together, so that result belongs to the package rather than to the stubble. At the other end, Davey and others surveyed 2,046 one kilometre squares of lowland England in 2005 and again in 2008 and found no consistent association between stubbles and farmland bird numbers, with grey partridge and tree sparrow the only species showing a more positive population change, and that effect small. Field and others surveyed 75 fields in East Anglia and the West Midlands in the winter of 2007 to 2008 and found no difference in seed-eating birds or skylark between Environmental Stewardship stubbles and non-stewardship stubbles.

Source: Conservation Evidence, action 695, supporting evidence from individual studies, checked 05/08/2026.

Conservation Evidence say themselves that the studies are not directly comparable or of equal value, and that study size, design, reported metrics and relevance to your own situation matter more than "simply counting the number of studies that support a particular interpretation". The individual studies listed run from 2000 to 2010, so all of them predate this scheme and this action.

Source: Conservation Evidence, action 695, checked 05/08/2026, including the note under key messages.

What we have not found. We have not found published work measuring a stubble held to mid-summer rather than to February or March, which is the thing this action actually pays for. Nor anything that measures AHW7 itself, which is no surprise given how new it is.

What the sources say makes it work better. All of the following comes from the studies listed on that same Conservation Evidence page, and it is a description of what was found rather than advice from us.

Barley came out ahead of wheat twice. Moorcroft and others, across 122 stubble fields on 32 farms in central England in the winters of 1997 to 1999, found linnet, skylark, reed bunting and corn bunting more frequently on intensively farmed barley stubbles than on wheat, and recorded 51 per cent weed cover on those barley stubbles against 40 per cent on intensive wheat. A Defra-funded study of 205 stubble fields in south Devon in the winter of 2003 to 2004 found barley stubbles following low-input herbicide more beneficial to cirl bunting than wheat or conventionally managed stubbles, with roughly four times the seed abundance and broadleaved weed cover, and reported that seed-eating species generally preferred barley.

The same Devon study found that fields where stubbles were grazed over winter carried significantly lower densities of seed-eating birds.

On height the two UK studies disagree. Butler and others, on 20 split wheat fields across 12 farms in central England in the winter of 2003 to 2004, found seed-eating songbirds and invertebrate-feeding birds more abundant on stubble cut to about 6 cm, while skylark and partridges were more abundant on uncut stubble of about 14 cm. Whittingham and others, in central England the following winter, found seed-eaters and invertebrate feeders at higher densities on uncut stubble instead, along with skylark, partridges, pigeons and meadow pipit.

The Whittingham study also found skylarks and invertebrate feeders at higher densities on scarified, meaning lightly tilled, sections of fields than on unscarified control sections.

On what follows the stubble, a 2002 review by Evans and others of the Pilot Arable Stewardship Scheme found overwinter stubbles benefited plants, bumblebees and true bugs, and that this was especially so where the stubble was followed by a spring fallow.

On how much of it, Gillings and others in 2005 found national population trends of 16 out of 26 bird species were positively influenced by the presence of overwinter stubbles, and predicted ten-year population stability or growth for yellowhammer and skylark if stubble within a one kilometre square reached 15 and 20 hectares respectively.

Source: Conservation Evidence, action 695, background information and supporting evidence from individual studies, checked 05/08/2026.

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.

Three of them line up with what AHW7 already says. Grazing over winter is prohibited by the action, so the grazing finding and the requirement run the same way. Stubble height may never be a live question, because topping is prohibited too. And GOV.UK's own advice section suggests cultivating the stubble area in March, which is the same operation Whittingham's scarified plots amount to, though the page is explicit that this is advice rather than a requirement.

Two of them do not. The Gillings figure is a landscape prediction from a model rather than a measured outcome on one farm, and nothing in this action asks you to meet it. And the rest is really a decision about the crops either side of the stubble year rather than about the stubble itself: what you grow in front of it, how you spray that crop, what goes in behind it. What you are paid against is the GOV.UK page.

What you actually have to do

After harvest, leave the stubble from a cereal crop, oilseed rape or linseed until around mid-summer in the following year. Do not apply pre-harvest desiccants to the crop that produces that stubble. On the stubble itself: no topping, no grazing, no fertilisers, manures or lime, and no pesticides except herbicides to control grass weeds, sprayed on the affected area, from around mid-May.

You also have to identify the land as not being at risk of soil erosion or surface runoff, and keep written evidence that you have.

The window is expressed in seasons rather than dates. If the start date makes it too late in the first year, start within 12 months of the action's start date. In the final year, run until around mid-summer or the end date, whichever comes first.

Source: GOV.UK, AHW7 action page, checked 02/08/2026.

What you cannot do on it

No pre-harvest desiccant on the crop. No topping, no grazing. No fertiliser, manure or lime. No pesticides, with the single exception of herbicides to control grass weeds, sprayed on the affected area, from around mid-May.

GOV.UK's advice section suggests cultivating the stubble area in March to create bare ground nesting plots and encourage spring-germinating rare arable flora. That advice is explicitly not part of the requirements.

Source: GOV.UK, AHW7 action page, checked 02/08/2026.

Where it can go, and the cap

Agricultural land below the moorland line, on arable land used to grow cereals other than maize or sorghum, oilseed rape or linseed, and identified by you as not being at risk of soil erosion or surface runoff. SSSIs need consent first. Land with historic or archaeological features needs an SFI HEFER first. It is rotational, so it moves within your crop rotation in years two and three. Total or part of a parcel.

Source: GOV.UK, AHW7 action page, checked 02/08/2026.

AHW7 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, AHW9 and AHW11. How the 25 per cent limit works.

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

What you can stack it with

The compatibility lists are on the GOV.UK action page, set out separately for actions on the same area and actions on the rest of the parcel. CIPM4, no use of insecticide, appears on the same-area list. CIPM4 requires the action to be done on at least one crop sown in each of its three years, and its eligible land covers exclude fallow land and temporary grassland.

Source: combinations, GOV.UK AHW7 action page, checked 02/08/2026. CIPM4 sown crop timing requirement and land cover exclusions, GOV.UK CIPM4 action page, checked 02/08/2026.

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.

The desiccant rule looks backwards in time. The prohibition is on the crop that produces the stubble, not on the stubble. So the decision that determines whether a field can go into this action is made at the end of the previous crop, before the action's ground is even a stubble. It lands with whoever plans the pre-harvest spray rather than with whoever manages the stubble.

"Around mid-May" and "around mid-summer" are the wording, not a paraphrase. GOV.UK gives no calendar dates for this action. 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 herbicide exception is narrow in three ways at once. Grass weeds only, sprayed on the affected area only, from around mid-May only. A broadleaf problem in March does not fit any of the three.

Rotational means it moves. Years two and three go somewhere else in the rotation. That is a planning constraint on the whole cropping plan rather than on one field, and it is easier to agree to in the application than to honour in the third year.

The 25 per cent cap is shared, not per action. AHW7 draws on the same limited area allowance as CAHL2, winter bird food, which is the action most likely to be sitting next to it in an arable application. Whatever goes into one is not available to the other, so the two are worth totalling together before the form is filled in rather than decided separately.

The not-at-risk assessment is yours to make and yours to write down. The requirement is that you identify the land as not at risk of soil erosion or surface runoff and keep written evidence of it. That is a document that has to exist, made by you, before the action rather than after.

A full cropping year, not a winter. The word overwinter in the title undersells the length of it. The stubble stands from harvest to around mid-summer the following year, which is why the comparison above is against a cropping year rather than against a cover crop.

Keeping the evidence

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

Two separate records. First, the erosion and runoff assessment, which GOV.UK explicitly says you must keep in writing and which it says can come out of the soil management plan produced for CSAM1 or SAM1. Second, evidence of what you have done, with field operations at parcel level and their invoices, and photographs or other documentation, given as the examples.

Source: GOV.UK, AHW7 action page, checked 02/08/2026.

The awkward thing about showing you have done this action is that it is largely an action of not doing things, and there is no invoice for a pass you did not make. What that suggests to us is that the useful record here is the negative one: a spray and operations record for the parcel that runs across the whole period and shows what went on it, which happens also to be the record that shows the desiccant did not. Dated photographs across the winter and spring are the other half, since a stubble in September and a stubble in June look nothing alike.

The part only your own ground can answer

The gap above is worked on national averages, and the whole case for this action rests on the block being one that returns below your own rotation average. Which block that is, and by how much, sits in your own yield records rather than in a national survey. Tilth keeps them field by field alongside the operations record that shows what did not go on the stubble. Request an invite.