Agricultural Land Classification Map: How to Check Your Land Grade

Before a developer, an agent or a council discusses solar on your fields, the question that usually comes first is what grade the land is. This page is a lookup guide: which map to open, what each one can and cannot tell you, and when a map is not enough. For what the grades mean and how planning policy treats each one, read our full guide to agricultural land classification and solar. SEO Dons is an independent publisher, not a soil surveyor; a grade used in a planning decision has to come from a qualified field survey.

Which ALC map to use

Map or dataset	Covers	Detail	Shows 3a and 3b?	Best use
Predictive ALC map (Defra, April 2026)	All of England	Strategic, user scale 1:250,000	Yes	A first look at where you probably stand
Provisional ALC map (MAFF, 1967 to 1974)	England and Wales	1:250,000; five grades only	No: grade 3 is not split	Historic reference; replaced as the national overview in April 2026
Post-1988 detailed survey polygons (Natural England)	Only land that has been surveyed	Field by field	Yes	The strongest evidence where your fields fall inside a surveyed area
Wales Predictive ALC map (DataMapWales)	Wales	Predictive, strategic	See the Welsh Government page	Deciding whether a survey is needed
Land Capability for Agriculture (Scotland)	Scotland	James Hutton Institute dataset, seven classes	Different system	Scottish land grading; classes 1 to 3.1 are often called prime agricultural land

How to check your grade, step by step (England)

1. Open the Predictive ALC map. It is published through the Defra Data Services Platform and covers every field in England, including the 3a and 3b subgrades. Treat the result as a starting point.
2. Switch on the survey layers in MAGIC. Defra’s MAGIC map (magic.defra.gov.uk) can show the ALC post-1988 survey polygons. If your fields sit inside one, you will see a detailed grade rather than a prediction.
3. Look for a survey report. Natural England makes detailed ALC survey reports available through its publications site. A report shows where the borings were taken and which limitation set each grade.
4. Compare the sources. A field the predictive map calls grade 3 may sit inside a detailed survey that grades it 3a or 3b. Where they disagree, the detailed survey wins.
5. Decide whether you need a survey. If a ground-mounted scheme on grade 3 land is on the table, assume the council will ask for one.

How accurate is the Predictive ALC map?

It is modelled from national soils data using the standard 1988 methodology. Cranfield University’s final report to Defra (project RDE118) says about 60% of England’s land area has the same grade as on the provisional map once 3a and 3b are merged for the comparison, around 20% improved by one grade and less than 20% went down. That is a reasonable overview and a poor basis for a single field: Natural England’s planning guidance is clear that maps at that scale are not suitable or accurate enough to assess individual fields or sites. The government has also said that the format of ALC surveys can vary from project to project and that no accredited body oversees them, so if a developer hands you a survey, ask who did it, when, and whether the boring density matches the guidance.

When a map is not enough: what a survey involves

Natural England’s guidance sets the standard method: a soil specialist makes auger borings on a regular grid, about one per hectare, down to roughly 1.2 metres, backed up by inspection pits dug to at least a metre. Each boring is assessed for climate, site and soil limitations, and the land takes the grade of its single most limiting factor. The report maps the grade of each part of the site and names the limiting factor. For solar, a survey is usually commissioned for any ground-mounted array on grade 3 land, any site where the mapping hints at best and most versatile (BMV) land, and larger schemes. In Wales, Welsh Government guidance says applications should include survey evidence where they cover grade 1, 2 or 3a land.

What the grade means for a solar scheme

Best and most versatile land is grades 1, 2 and 3a under the National Planning Policy Framework. A scheme on BMV land carries a heavier burden of justification, and councils must consult Natural England where a proposal not in line with the development plan would lose 20 hectares or more of BMV land. Grade 3b, 4 and 5 land is not BMV and is the easier planning case. The line between 3a and 3b often comes down to soil wetness or droughtiness measured in a pit, which is why a map alone rarely settles it. Our guide to planning permission for ground-mounted solar on farmland explains what the council will ask next, and the solar farm land calculator shows how many acres a scheme might take and the planning flag that goes with your grade.

Next steps

If you have been approached by a developer, check the grade first, then read the solar farm land lease guide and our guide to solar farm developers before replying. For the bigger picture on options, see solar panels on farmland.

Frequently asked questions

Is there a map of agricultural land grades for my land?

Yes. In England the Predictive ALC map (Defra, April 2026) covers every field, including the 3a and 3b subgrades, and MAGIC shows detailed post-1988 survey polygons where land has been surveyed. Wales has its own Predictive ALC map, and Scotland uses Land Capability for Agriculture classes.

Can I use the Predictive ALC map in a planning application?

Not to prove the grade of a field. It is a strategic dataset at 1:250,000 scale, and Natural England’s guidance says maps at that scale are not suitable or accurate enough for individual fields or sites. Grade 3 land is normally graded by a field survey.

What is the difference between grade 3a and 3b?

Grade 3a is good quality land and counts as best and most versatile land; grade 3b is moderate quality and does not. The difference often rests on soil wetness or droughtiness assessed in a soil pit.

Sources

• Defra Predictive Agricultural Land Classification Map for England (April 2026): strategic 1:250,000 user scale; includes grade 3 subgrades
• Defra project RDE118 final report summary (Cranfield University): comparison with the provisional map
• Natural England: ALC grades, post-1988 survey polygons
• Natural England guidance on assessing development proposals on agricultural land (updated July 2026): survey method; consultation at 20 hectares of BMV land
• Welsh Government: Predictive ALC map on DataMapWales
• Land Capability for Agriculture (Scotland): James Hutton Institute dataset