How to identify and maintain the 5 main soil types.
This guide provides information on how to identify the 5 main soil types, outlines the main characteristics of each soil type and how to maintain good soil structure. It also explains how to assess soil structure and organic content and protect soil from erosion, organic matter decline, compaction and contamination.
It introduces the cross compliance soil management standards you must comply with in order to protect the soil, and offers guidance on how to do this.
It gives you information and contact details for organisations that can advise and help you to protect the quality of your soil.
Identifying soil types and soil structure
As a farmer, you will need to know the differences between different soil types and structures. There are 5 main types of soil:
- sandy and light silty soils
- medium soils
- heavy soils
- chalk and limestone soils
- peaty soils
Assess the soil structure on your farm
To check the structure of your soil, you should dig a hole and examine the exposed soil, looking for the following characteristics:
Characteristics of well-structured and poorly structured soils
|Well structured||Plenty of spaces or pores between the aggregates. You can easily crumble moist soil clumps between your thumb and finger.||Larger blocks or clumps than the topsoil, with many vertical cracks or channels. It can easily be broken apart when moist.|
|Poorly structured||Dense aggregates of soil with few pores. You will find it hard to break the clumps apart even when the soil is moist.||Also dense and may form a hard pan with few pores or cracks in the soil. Below the pan, the soil structure may be satisfactory, or the compaction may go deeper into the subsoil.|
Good soil structure is very important for agriculture, as it can:
- increase crop yields
- improve the quality of crops and grassland
- reduce the risk of environmental damage - such as water pollution, risks of drought and flooding
If you have poorly structured soil on your land, this can also cause problems, including:
- patchy germination of grass or crops
- poor growth and greater vulnerability to disease
- poor drainage - which can lead to increased runoff, erosion and diffuse pollution of watercourses
- surface capping - which can make it hard for plants to grow and can also cause runoff and erosion
You can also find help on identifying soil issues on your farm in the Environment Agency’s ‘Think soils’ manual on soil assessment to avoid erosion and run off.
There may be events you can attend in your local area that will provide copies of ‘Think soils’, along with some useful advice. You can find out about local events by calling the Environment Agency helpline on 03708 506 506.
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Maintaining good soil structure
If you receive Single Payment Scheme (SPS) funding or other direct payments, you need to meet cross compliance requirements. The main cross compliance standards of good agricultural and environmental conditions (GAECs) for soil management are now incorporated into GAEC 1 and cover:
- the Soil Protection Review (SPR), which aims to maintain soil structure and organic matter, and to prevent erosion
- post-harvest management of land, which applies if you mechanically harvest combinable crops, and aims to protect post-harvest land from runoff and erosion
- waterlogged soil, which bans the use of tractors and other motor vehicles on waterlogged land, in order to maintain soil structure and prevent compaction
- burning of crop residues, which bans the burning of many combinable crop residues, in order to maintain soil organic matter and protect landscape features
GAEC standards also require you to protect your soils in order to maintain biodiversity in local habitats for wildlife and wild plants, as well as protecting landscape features.
You can find out more about cross compliance standards of GAECs for soil management in the guide on soil use.
Identify areas of your farm most at risk
Creating a map highlighting areas of your farm that are most vulnerable to soil erosion and soil runoff can help you to manage these soil problems. You can download a Department for Environment, Food and Rural Affairs (Defra) sample risk map in the Guidance for Farmers in Nitrate Vulnerable Zones (NVZ)
Measures to maintain good soil structure
The two main problems affecting the quality of your soil are compaction and capping.
Compaction is where the soil becomes squashed together, reducing the space within the soil for air and water, which makes it harder for plants to grow properly. You can reduce this by taking the following measures:
- avoid cultivating wet soil, where possible
- reduce the use of heavy vehicles on fields
- loosen the top soil regularly
- regularly conduct a check of the subsoil in your fields for signs of compaction, especially after wet weather and during cultivation or harvest
- remove any already compacted soil that you find
Capping takes place when the surface of the soil is broken up by prolonged, heavy rain. Once it dries, this forms a ‘cap’ or hard layer over the underlying soil. You can protect soil from erosion by taking the following measures:
- work across a sloped field whenever this is safe and possible, but beware of creating slope patterns that may channel runoff
- maintain crop cover in winter for as long as possible
- increase the amount of organic matter in your soil to bind it - within the permitted levels of use of farm waste
- avoid sowing late-harvested crops, eg potatoes or sugar beet, on fields that are more at risk of erosion and runoff, or ensure that you harvest them first in drier conditions
- plant trees, hedges or grass buffer strips to prevent soil erosion and runoff into rivers and roads
- manage livestock to avoid trampling of pasture into wet, muddy patches - this is known as ‘poached soil’
- avoid out-wintering livestock on slopes if runoff problems are likely to cause soil erosion
Managing sandy and light silty soils
Sandy and light silty soils naturally drain water well. However, sandy and light soil structure is often weak as it contains little clay or organic matter to bind it together, making it prone to erosion.
You will also need to manage other problems associated with this type of soil:
- capping - this is where the surface is easily broken up by rain and forms a ‘cap’ or hard layer over the underlying soil once it dries
- slumping - the topsoil may fall apart, causing the soil to slump; the soil may then set solid when it dries out
If you don’t protect these types of soil from such problems, they will be damaged by runoff, soil wash and erosion by wind and water.
You can protect sandy and light silty soils by taking the following measures:
- sow winter cereals early to achieve good crop cover before winter
- harvest potatoes, vegetables and forage crops by ploughing deeper than usual when the weather is suitable
- avoid direct drilling because these soils tend to slump and will need regular loosening
- avoid growing potatoes, vegetables, maize and other forage crops on slopes if runoff is likely to cause soil erosion
- sow nurse crops (plants that assist the growth of the main crop) such as barley to prevent wind erosion, particularly in vegetable crops or sugar beet grown on unsheltered land that is exposed to strong winds
Managing medium soils
You can manage medium soils on your farmland by using key elements of organic soil management, including:
- ploughing and cultivating at the correct time, to minimise nutrient losses through leaching
- liming to provide the optimum pH for nutrient release
- avoiding bare ground over winter, to reduce leaching
- regular use of a ‘shakerator’ or ‘subsoiler’ to break up soil pans and improve drainage
You can also protect your medium soils by taking the following measures:
- cultivate and harvest in dry weather where possible, to avoid soil compaction
- examine the soil structure (especially after late harvesting of crops) and remedy any damage when weather permits
- if tramlines cause runoff, loosen them with a tine or ‘subsoiler’ when weather and soil condition permits - the soil should be friable
Managing heavy soils
Heavy soils contain clay, which helps bind soil particles together into clumps or aggregates. Well-structured heavy soil will crumble easily in your hand, but poorly structured heavy soil will not. The structure of heavy soil is determined mainly by the amount of organic matter in the soil. Organic matter helps to keep the clay particles apart, so there is space for air and water.
Without an adequate supply of organic matter, heavy soil is likely to become compacted. It will not retain moisture or be able to drain. Compacted heavy soil will easily become waterlogged, and suffer from ponding, runoff and soil wash.
You can protect heavy soils by taking the following measures:
- avoid crops that are harvested or grazed in late autumn or winter - or crops that need ploughing or other primary cultivation in the spring, when subsoils are still wet
- drain your land - however, to comply with GAEC 5 - environmental impact assessment - you must not drain natural wetlands unless you have consent under the Environmental Impact Regulations - see the guide on Environmental Impact Assessments (EIA)
- use moling, draining or subsoiling as secondary treatments over pipe drains that have a permeable backfill
- regularly maintain field drains
- clean your ditches and cut their banks in rotation only in autumn or early winter
- each spring and autumn, inspect any heavy soils for poor structure and compaction, and plan to subsoil by ploughing the layer beneath the topsoil
- reseed pasture which has been made wet and muddy (poached) or loosen the compact topsoil - but avoid bringing soil with low organic matter to the surface
- avoid spreading manure and slurry when the soil is wet, especially if there is a risk of runoff and pollution
Managing chalk and limestone soils
Limestone and chalk soils often have a shallow layer of topsoil over the rock below. These soils usually have a good structure and are free draining, but if you cultivate these soils on hillsides, there is a risk of tillage creep. This is where the soil gradually slides down the hill, exposing the rock. These soils are also liable to runoff and erosion on slopes, particularly from compacted headlands and tramlines.
You can protect chalk and limestone soils by taking the following measures:
- avoid deep ploughing, especially into the rock
- work and sow crops across a slope where possible
- turn soil up the slope when ploughing, where possible
- loosen tramlines to increase infiltration of water
- subsoil compacted gateways and headlands, during dry enough weather
- carry out only minimum cultivation on thin chalk and limestone soils
Managing peaty soils
To protect and manage any peaty soil on your land, you should:
- sow a ‘nurse crop’ to provide shelter for spring crops before drilling - this will prevent wind erosion of your fenland soils
- reduce wind erosion with shelterbelts - a plantation of trees or shrubs that act as a wind break
- follow environmental impact assessment regulations if you want to bring undrained lowland and upland peat bogs into intensive agricultural production - see the guide on EIA
- minimise damage to plant cover on upland or lowland peat soil by complying with GAEC 9 on overgrazing and unsuitable supplementary feeding - see the guide on hill farming.
- ensure you protect your heathland soils from erosion when carrying out controlled burning - see the guide on heather and grass burning
Organic soil management
Correct soil management is crucial on an organic farm. The soil must provide most of the nutrients for crop and grass growth.
Sources of nutrients
Soil - and the rock minerals and organic matter contained in it - provide many of the nutrients for plant growth on an organic farm.
Leguminous plants - particularly clovers - are an important source of organic matter and soil fertility. Nodules on their roots convert nitrogen in the air into soluble nitrate ‘fertiliser’ which passes into the surrounding soil.
Farmyard manures, composts and slurries also provide organic nutrients for soil - including phosphate, potash and other nutrients.
If you are applying any organic or inorganic waste materials to your land you must comply with the relevant waste exemption or permit, which can be obtained from the Environment Agency.
If you are using high-quality, source-separated green compost on your farm, you may be able to use The Compost Quality Protocol which removes the need for regulatory controls. You can download compost quality protocol guidance
You should always store your manure and slurry in a way that prevents loss of nutrients. (Manure should be stored in field heaps and slurry in a sealed tank.) You can also compost manures, which makes the product more stable.
As well as increasing and protecting the organic matter in your soil, there are several other key elements of organic soil management, including:
- timing your ploughing and cultivation correctly to prevent losing your soil’s nutrients from leaching or from being released in to the atmosphere
- liming your soil to provide the optimum pH for nutrient release
- reducing leaching of nutrients by keeping ground cover on your soil over winter
- regular cultivation such as subsoiling, lifting or ploughing, or by using a shakerator, to break up soil pans and improve drainage
Environment Agency Agricultural Waste helpline 0845 603 3113
Environment Agency helpline 03708 506 506
Soil Association Farmers’ and Growers’ enquiries 0117 914 2400
Environment Agency Incident hotline 0800 80 70 60
Natural England Enquiry Service 0845 600 3078
RPA Customer Service Centre 0845 603 7777
Defra helpline 08459 33 55 77
Cross Compliance helpline 0845 345 1302
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Download the ‘Think soils’ manual
Download Defra’s NVZ guidelines for farmers
Download compost quality protocol guidance