Guide to assessing development proposals on agricultural land

Updated 5 February 2021

Applies to England

1. Policies to protect agricultural land and soil

Developers and local planning authorities (LPAs) should refer to the following government policies and legislation when considering development proposals that affect agricultural land and soils. They aim to protect:

  • the best and most versatile (BMV) agricultural land from significant, inappropriate or unsustainable development proposals
  • all soils by managing them in a sustainable way

Natural England uses these policies to advise on development proposals as a statutory consultee in the planning process.

1.1 A Green Future: Our 25 Year Plan to improve the Environment 2018

A Green Future: Our 25 Year Plan to Improve the Environment sets out the government’s 25-year plan to improve the health of the environment by using natural resources more sustainably and efficiently. It plans to:

  • protect the best agricultural land
  • put a value on soils as part of our natural capital
  • manage soils in a sustainable way by 2030
  • restore and protect peatland

1.2 National Planning Policy Framework (NPPF)

LPAs should use the NPPF to make decisions about the natural and local environment to:

  • protect and enhance landscapes, biodiversity, geology and soils
  • recognise soils as a natural capital asset that provide important ecosystem services
  • consider the economic and other benefits of BMV agricultural land, and try to use areas of poorer quality land instead of higher quality land
  • prevent soil, air, water, or noise pollution, or land instability from new and existing development

Read Chapter 15: Conserving and enhancing the natural environment for full details.

1.3 Town and Country Planning (Development Management Procedure (England) Order) (DMPO) 2015

Planning authorities must consult Natural England on all non-agricultural applications that result in the loss of more than 20 hectares (ha) of BMV land if the land is not included in a development plan. For example, this includes the likely cumulative loss of BMV land from the proposed development if it’s part of a phased development.

This is required by schedule 4(y) of the Order.

1.4 Planning Practice Guidance for the Natural Environment

Paragraphs 001 and 002: Planning Practice Guidance for the Natural Environment explain why planning decisions should take account of the value of soils and agricultural land classification (ALC) to enable informed choices on the future use of agricultural land within the planning system.

2. LPAs: consult Natural England

You must consult Natural England for development proposals that are both:

  • likely to cause the loss (or likely cumulative loss) of 20ha or more of BMV land
  • not in accordance with an approved development plan

Natural England will advise you on the level of impact the proposal may have on BMV agricultural land. Natural England will take into account the type of development and its likely long-term effects.

Email or write to:

Natural England consultation service
Hornbeam House
Electra Way
Crewe Business Park

3. LPAs: how to use agricultural land classification (ALC)

You can use ALC to help inform decisions on the appropriate sustainable development of land.

ALC uses a grading system to enable you to assess and compare the quality of agricultural land in England and Wales.

A combination of climate, topography and soil characteristics and their unique interaction determines the limitation and grade of the land. These affect the:

  • range of crops that can be grown
  • yield of crop
  • consistency of yield
  • cost of producing the crop

4. About ALC grades

ALC is graded from 1 to 5.

The highest grade goes to land that:

  • gives a high yield or output
  • has the widest range and versatility of use
  • produces the most consistent yield
  • requires less input

BMV agricultural land is graded 1 to 3a.

4.1 Grade 1 – excellent quality agricultural land

Land with no or very minor limitations. A very wide range of agricultural and horticultural crops can be grown and commonly includes:

  • top fruit, for example tree fruit such as apples and pears
  • soft fruit, such as raspberries and blackberries
  • salad crops
  • winter harvested vegetables

Yields are high and less variable than on land of lower quality.

4.2 Grade 2 – very good quality agricultural land

Land with minor limitations that affect crop yield, cultivations or harvesting. A wide range of agricultural and horticultural crops can usually be grown. On some land in the grade there may be reduced flexibility due to difficulties with the production of the more demanding crops, such as winter harvested vegetables and arable root crops. The level of yield is generally high but may be lower or more variable than grade 1.

4.3 Grade 3 – good to moderate quality agricultural land

Land with moderate limitations that affect the choice of crops, timing and type of cultivation, harvesting or the level of yield. Where more demanding crops are grown yields are generally lower or more variable than on land in grades 1 and 2.

4.4 Subgrade 3a – good quality agricultural land

Land capable of consistently producing moderate to high yields of a narrow range of arable crops, especially cereals, or moderate yields of crops including:

  • cereals
  • grass
  • oilseed rape
  • potatoes
  • sugar beet
  • less demanding horticultural crops

4.5 Subgrade 3b – moderate quality agricultural land

Land capable of producing moderate yields of a narrow range of crops, principally:

  • cereals and grass
  • lower yields of a wider range of crops
  • high yields of grass which can be grazed or harvested over most of the year

4.6 Grade 4 – poor quality agricultural land

Land with severe limitations which significantly restrict the range of crops or level of yields. It is mainly suited to grass with occasional arable crops (for example cereals and forage crops) the yields of which are variable. In moist climates, yields of grass may be moderate to high but there may be difficulties using the land. The grade also includes arable land that is very dry because of drought.

4.7 Grade 5 – very poor quality agricultural land

Land with very severe limitations that restrict use to permanent pasture or rough grazing, except for occasional pioneer forage crops.

5. LPAs: carry out ALC assessments to support your planning decisions

For an overview of ALC use:

These maps are not at a scale suitable or accurate for assessment of individual fields or sites.

You can assess if a development proposal is likely to affect BMV agricultural land by using the post 1988 ALC Magic map and detailed site survey reports.

If no site survey reports are available, a new detailed survey may be necessary.

6. Use ALC to support your planning decisions

Use ALC survey data to assess the loss of land or quality of land from a proposed development. You should take account of smaller losses (under 20ha) if they’re significant when making your decision. Your decision should avoid unnecessary loss of BMV land.

6.1 Protect soil

You should make sure development proposals include plans to:

6.2 Carry out new surveys

If there’s not enough information from previous data, you may need to have a new field survey to plan for development or to inform a planning decision. You should use soil scientists or experienced soil specialists to carry out new surveys. They should be:

  • members of the British Society of Soil Science, the British Institute of Agricultural Consultants or similar professional body
  • knowledgeable about the ALC 1988 guidelines
  • experienced in soil description and ALC assessments

6.3 Survey requirements

For a detailed ALC assessment, a soil specialist should normally make boreholes:

  • every hectare on a regular grid on agricultural land in the proposed development area
  • up to 1.2m deep using a hand-held auger

They should:

  • dig small inspection pits by hand to a minimum depth of 1m to add supporting evidence to the borehole data
  • dig pits where there’s a change in main soil type and ALC grade to provide a good depiction of the site
  • combine the survey results with local climate and site data to plot on an Ordnance Survey (OS) base map
  • use a base map at an appropriate scale for detailed work, such as 1:10,000 scale

7. Developers: check if your proposal affects agricultural land

Use the post 1988 ALC Magic map and detailed site survey reports to help you assess whether a development proposal is likely to affect BMV agricultural land. If no suitable data exists, you may need to carry out a detailed survey to support your planning application.

7.1 Free and chargeable advice

Natural England offers advice for proposals. Some initial advice is free. More detailed advice is chargeable, for example if your proposal is 20ha or more and requires more detailed advice.