Agricultural Land Classification and Solar: What Your Land Grade Means

Updated 8 October 2026 · SEO Dons Editorial

If you have been approached about a solar scheme on your land, or are thinking of putting panels on a field yourself, the grade of that land will come up early. Agricultural Land Classification (ALC) is the system planners in England and Wales use to judge how good farmland is, and the better the grade, the harder it is to justify covering it with a ground-mounted array. This guide explains how the grades work, how to find yours, what a survey involves and how current planning policy treats each grade. For the wider picture on siting panels in fields, start with our parent guide to solar panels on farmland.

What Agricultural Land Classification is

ALC grades land according to how far its physical or chemical characteristics impose long-term limits on agricultural use. It is the only approved system for grading farmland quality in England and Wales. The grading rules were set out by the old Ministry of Agriculture, Fisheries and Food (MAFF) in 1988. In December 2025 Defra and the Welsh Government published an updated edition of the guidelines (Natural England reference JP069), but it made no changes to the grading criteria or the reference climate data, so a survey done to the 1988 rules is graded on the same basis today.

A surveyor looks at three groups of factors:

Climate – temperature, rainfall, aspect, exposure and frost risk. Warmer, moderately wet, sheltered land grades better.
Site – gradient, micro-relief (uneven ground) and flood risk, all of which affect what machinery can do and which crops are safe to grow.
Soil – texture, structure, depth, stoniness and chemical limitations.

Climate, site and soil then interact to produce three further limitations: soil wetness (how far excess water restricts crop growth and the days you can work the land), droughtiness (how much water the soil profile can hold for a crop through summer) and erosion. The land takes the grade of its single most limiting factor. A good loam can still drop to subgrade 3b if a slowly permeable clay layer near the surface makes it wet.

The ALC grades at a glance

The definitions below follow the wording Natural England uses in its planning guidance. Grade 3 is split into subgrades 3a and 3b, and that split is the one that matters most for solar.

Grade	Quality	What it means in practice	Best and most versatile?
1	Excellent	No or very minor limitations; high, consistent yields across a wide range of crops, including top fruit, soft fruit and salad crops	Yes
2	Very good	Minor limitations affecting yield, cultivation or harvesting; generally high yields, sometimes below grade 1	Yes
3a	Good	Consistently moderate to high yields of a narrow range of arable crops, especially cereals	Yes
3b	Moderate	Moderate yields of a narrow range of crops, principally cereals and grass	No
4	Poor	Severe limitations that significantly restrict the range of crops or level of yields; mainly suited to grass	No
5	Very poor	Very severe limitations; restricted to permanent pasture or rough grazing	No
Non-agricultural	Not graded	Land shown on ALC maps as not in agricultural use, so no grade is given	No
Urban	Not graded	Built-up land, shown as a separate category on ALC maps	No

What "best and most versatile" land means

Best and most versatile (BMV) land is land in grades 1, 2 and 3a. That definition is written into the glossary of the National Planning Policy Framework (NPPF) for England and into Planning Policy Wales.

For a landowner, the practical line runs between 3a and 3b. A field of 3b, 4 or 5 is not BMV, and a solar application on it does not have to clear the policy tests that apply to BMV land. A field of 3a is BMV, even though it may look and farm very like the 3b field next to it. Because the difference often comes down to soil wetness or droughtiness measured in a pit, you usually cannot tell which side of the line you are on without a survey.

ALC maps: provisional, post-1988 and the new predictive map

There are three sources of ALC information for England, and they are not equally reliable.

The Provisional ALC map. MAFF mapped the whole of England and Wales between 1967 and 1974, publishing the results as regional maps; today it is used as a 1:250,000 national dataset. It shows only five grades because it predates the subdivision of grade 3, so it cannot tell you whether grade 3 land is 3a or 3b. Grade 3 covers around half of the farmland in England and Wales, so for many farms the provisional map leaves the key question open. It was only ever meant as strategic guidance, not as evidence for an individual field.
Post-1988 detailed surveys. Since 1988, sites surveyed to the revised guidelines have been graded field by field, including the 3a/3b split, and the results are held by Natural England. Coverage is patchy, because land is only surveyed in detail when something, usually a development proposal, prompts it.
The Predictive ALC map (April 2026). Defra published a new Predictive Agricultural Land Classification map for England in April 2026, replacing the provisional map as the national overview. It is modelled from national soils data using the standard 1988 methodology and does show subgrades 3a and 3b. The final report on the map, prepared by Cranfield University for Defra (project RDE118), says about 60% of England's land area has the same grade as on the provisional map (with 3a and 3b merged for the comparison), around 20% improved by one grade and less than 20% went down.

The predictive map is a strategic, national dataset (Defra gives its user scale as 1:250,000). Natural England's planning guidance is clear that maps at that scale are not suitable or accurate enough to assess individual fields or sites. Use it to see where you probably stand, not to prove a grade in a planning application.

How to find your land's grade

Check MAGIC. Defra's MAGIC map (magic.defra.gov.uk) lets you switch on ALC layers, including the post-1988 survey polygons. If your fields fall inside a surveyed area you will see a detailed grade.
Look up any survey report. Natural England makes detailed ALC survey reports available through its publications site. The report shows boring locations and the limitation behind each grade.
Check the Predictive ALC map. It is available through the Defra Data Services Platform and covers every field in England, including the 3a/3b split, at a strategic scale.
Commission a survey if the answer matters for a decision, which it will if a developer is proposing a ground-mounted scheme.

When an ALC survey is needed and what it involves

A detailed ALC survey is normally commissioned when a planning application would take agricultural land out of use and the existing information cannot settle the grade. For solar that usually means any ground-mounted array on grade 3 land, any site where the mapping hints at BMV land, and larger schemes where agricultural land is assessed as part of the environmental work. In Wales, Welsh Government guidance says planning applications should include survey evidence where they cover grade 1, 2 or 3a land.

Natural England's guidance sets out the standard method:

A soil specialist makes auger borings every hectare on a regular grid, down to about 1.2 m with a hand-held auger.
Borings are backed up by inspection pits dug to at least 1 m, to check soil structure, stone content and how freely the subsoil drains.
Each boring is assessed against the climate, site and soil limitations above; laboratory checks are sometimes used to confirm soil texture or stone content.
The report maps the grade of each part of the site, gives the area of each grade and names the limiting factor.

Natural England's older Technical Information Note TIN049 (second edition, 2012) covered the same ground, and the current gov.uk guidance on assessing development proposals on agricultural land, updated in July 2026, is now the working reference. Survey consistency has been questioned: in May 2024 the government said the format of ALC surveys could vary from project to project and that no accredited body oversaw them, and said it was exploring an independent certification scheme for surveyors. If a developer gives you a survey, ask who did it, when, and whether the boring density matches the guidance.

How planning policy treats BMV land for solar in England

National policy changed in 2026, so older articles on this are out of date. A revised NPPF was published on 17 August 2026 with a new numbered structure, and its policies are material considerations from the day of publication. The parts that matter for a ground-mounted scheme are:

Policy N2 1(b) says development proposals should take into account the quality of agricultural land, including whether it is BMV and its grade, and that if significant development of agricultural land is necessary, poorer quality land should be used where possible.
Policy N1 1(c) asks development plans to avoid higher quality agricultural land where poorer land is available when steering where development goes.
Policy W3 says substantial weight should be given to the energy security, economic and net zero benefits of renewable and low carbon energy, and that applicants should not be required to demonstrate a need for it.

The May 2024 written ministerial statement "Solar and protecting our Food Security and Best and Most Versatile (BMV) Land" said large solar schemes should avoid BMV land in favour of brownfield, contaminated, industrial and lower-quality agricultural land, and asked councils to weigh the cumulative impact of several schemes in one area. The 2026 NPPF lists that statement in Annex A as one whose content has been fully or partially incorporated into the Framework or no longer represents up-to-date government policy. At least one council has already acted on this: a West Lindsey officer report in August 2026 treated the statement as no longer a material consideration. The 2026 policy on agricultural land quality, N2, does not mention food production; it asks for grade and BMV status to be taken into account and for poorer land to be used where possible.

Planning Practice Guidance on renewable and low carbon energy still lists the considerations for large ground-mounted solar farms. They include focusing schemes on previously developed and non-agricultural land; where greenfield land is involved, showing that using agricultural land is necessary and that poorer quality land has been used in preference to higher quality land; allowing continued agricultural use or biodiversity improvements around the arrays; and using conditions to make sure panels are removed and the land restored when the scheme ends.

When Natural England is consulted

Natural England is a statutory consultee on agricultural land. Councils must consult it on non-agricultural applications that would lead to the loss (or cumulative loss) of 20 hectares or more of BMV land and that are not in line with an approved development plan. Below that threshold the council weighs land quality itself, using whatever survey evidence the applicant provides.

What your grade means for a ground-mounted scheme

Your land	What to expect at planning
Grade 1 or 2	BMV. The applicant should expect to show why agricultural land is needed and why poorer land was not used. Expect close scrutiny, and a Natural England consultation if 20 ha or more of BMV land would be lost outside the development plan.
Subgrade 3a	BMV, with the same policy tests. A detailed survey is essential, because the boundary with 3b is often decided by wetness or droughtiness found in the pit.
Subgrade 3b	Not BMV. Land quality still has to be taken into account, but the BMV tests do not apply.
Grade 4 or 5	Poorer quality land, which national policy and guidance point schemes towards. Other issues such as landscape, heritage, flood risk and grid access usually decide the outcome.

Grade is one factor among many. A scheme on grade 4 land can still fail on landscape or heritage grounds, and one on BMV land is not automatically refused. If you are weighing an offer from a developer, our solar farm land lease guide covers rents, terms and what to check in heads of terms. Where a developer proposes grazing or cropping under the panels, see our note on agrivoltaics.

Wales: the Predictive ALC Map and Planning Policy Wales

Wales uses the same ALC grades and the same 2025 guidelines, published jointly with Defra. The Welsh Government publishes its own Predictive ALC Map on DataMapWales, which shows the likely grade of land and is meant to help decide whether a survey is needed. BMV land (grades 1 to 3a) makes up only about 10 to 15% of land in Wales.

Policy in Wales is firmer than in England. Planning Policy Wales (paragraphs 3.58 and 3.59) says BMV land should be conserved as a finite resource for the future and that considerable weight should be given to protecting it. Grades 1, 2 and 3a should only be developed if there is an overriding need and previously developed or lower-grade land is unavailable, and where land of different grades is available, development should go to the lowest grade. Welsh Government guidance says planning applications covering grade 1, 2 or 3a land should include survey evidence.

Scotland: Land Capability for Agriculture

Scotland does not use ALC. It uses the Land Capability for Agriculture (LCA) system, originally developed by the Macaulay Institute and now held by the James Hutton Institute. Land is ranked into seven classes, from class 1 to class 7, according to how far soil, climate and relief limit its agricultural use and cropping flexibility. Classes 1 and 2 have no divisions, while some lower classes are split; class 3, for example, divides into 3.1 and 3.2. The national map is at 1:250,000, with larger-scale mapping for the main farming areas.

Classes 1, 2 and 3.1 are often referred to as prime agricultural land. Under Policy 5 of National Planning Framework 4 (NPF4), development on prime agricultural land is only supported for a short list of purposes, which includes renewable energy generation where secure provision is made for restoring the land, and the layout and design must keep the amount of protected land used to a minimum.

Rooftop solar: land grade does not apply

ALC is about land. Panels on the roof of a barn, grain store or livestock shed take no farmland out of use, so the grade of the surrounding fields is irrelevant. In England, rooftop solar on non-domestic buildings, including farm buildings, is generally permitted development under Part 14 Class J of the General Permitted Development Order, with no capacity cap; systems over 50 kW need prior approval from the council on design and external appearance, particularly glare. Listed buildings and scheduled monuments are excluded. If your best land is BMV, putting panels on roofs first and keeping fields in production avoids the land-quality question altogether. Our comparison of ground-mount vs rooftop solar sets out the trade-offs, and the main guide to solar panels for agriculture covers sizing and grid connection.

Next steps

Find your likely grade on MAGIC or the Predictive ALC map, then decide whether you need a detailed survey before you agree anything with a developer. Compare indicative figures with our cost guide and savings calculator, and check the current position on support in our grants and funding guide. If you are considering panels for your own use, send an enquiry through the form below: SEO Dons passes it to an installer covering your area, who can look at your buildings and land and quote. For a land lease or a developer's offer, take independent land-agent and legal advice before signing.

Frequently asked questions

Can I challenge the grade shown on a map for my land?

Yes, in practice. Neither the old provisional map nor the 2026 predictive map is accurate enough to grade an individual field, so the evidence that counts at planning is a detailed survey carried out to the published ALC guidelines. If a map or a developer's report puts your land in a grade you doubt, you can commission your own survey from a soil specialist and put that evidence forward.

Does a solar farm permanently lower the grade of my land?

ALC grades land on its physical characteristics, such as climate, slope and soil, not on its current use. Planning guidance describes solar farms as normally temporary structures and says conditions can be used to make sure panels are removed and the land restored when the scheme ends. Check the restoration and decommissioning terms in any lease carefully.

Is all grade 3 land classed as best and most versatile?

No. Only subgrade 3a is best and most versatile; subgrade 3b is not. Older maps that show plain grade 3 cannot tell you which subgrade applies, which is why so many solar sites need a detailed survey.

Who carries out an ALC survey?

ALC surveys are carried out by soil specialists, often commissioned through land agents or environmental consultancies. In May 2024 the government noted that the format of ALC surveys could vary between projects and that no accredited body oversaw them, and said it was exploring a certification scheme. Ask for the surveyor's experience, the survey date and the boring density before relying on a report.

Does the land grade matter if a developer leases my land rather than me building a scheme?

Yes. The developer's planning application will be judged partly on land quality, so a BMV site carries more planning risk and needs stronger justification. Our solar farm land lease guide covers what to check in an offer, and you should take independent land-agent and legal advice before signing.

Sources

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