Species selection

The success of fertility building crops depends on a number of factors such as soil type, species characteristics i.e. establishment rate and growth habits, timing of planting, how they are integrated with other crops and environmental conditions

What do I need to consider?

  • Specific aims and circumstances i.e. soil type, farming system, previous cropping, future cropping plans and climate.
  • Fertility building crops can be subject to pests and diseases; consider therefore cropping history and previous pest and disease problems before selecting the crop, and ensure it is not of the same 'type' as the vegetable or arable cash crop in a rotation.
  • Some legumes are more suitable than others as annual build-up crops due to differences in establishment rate and growth. Grain legumes i.e. lupins, peas and beans provide cash income but tend to fix less N, so are best suited to short-term N boosts in a rotation.

Need something long term?

  • A mix of red and white clover with perennial ryegrass can improve soil fertility and structure. The mix should be grown for 1 year before incorporation.
  • Red and white clover can fix up to 300 kg N/ha which is released rapidly after incorporation. The ryegrass acts like a sponge holding the nitrogen and delaying its release.
  • For leys that will be in the ground for longer than 2 years, mixing cocksfoot (which is drought resistant) and clover will help improve soil structure and add organic matter.

Winter mixes

Combining a nitrogen holder i.e. grazing rye and a fixer i.e. vetch can help improve soil over winter. They can be sown from mid-September until mid-October, and incorporated from February until late April.

Summer mixes

  • Fast growing annual green manures can add organic matter, suppress weeds, hold surplus soil nitrogen and act as a break crop by interrupting pest and disease cycles.
  • Up to 4 or 5 crops can be mixed i.e. mustard, crimson, clover, phacelia and Persian clover, and should be planted from late spring onwards on bare ground or immediately after whole crop silage or an early cereal harvest. It should be ready for turning after 8-10 weeks and can be incorporated before a winter cash crop.

Matching green manures to the soil type

All green manures will add organic matter and some species with be better suited to certain soils. This is a quick guide:

Acidic Soil

Alkaline soil

Neutral soil

Free-draining soil

Most green manures will not grow well

Sainfoin and lucerne will not thrive

Most green manures will thrive

Deep rooting grasses i.e. cocksfoot and tap rooted legumes such as sainfoin and red clover should be selected

Adapted from Sort Out Your Soil; A Practical Guide to Green Manures

Legume LINK project

The nationwide Legume LINK project LK09106, funded by DEFRA, investigated combining different legume and grass species in mixtures, incorporating a number of slower growing species. Replicated field experiments were conducted over three years at multiple locations, testing the performance of 12 legume species and 4 grass species sown in monocultures, as well as in a mixture of 10 of the legumes and all 4 grasses (the All Species mix, ASM).

The ASM contained: red clover, white clover, crimson clover, alsike clover, black medic, sainfoin, meadow pea, lucerne, large birdsfoot trefoil, birdsfoot trefoil, timothy, meadow fescue, Italian ryegrass and perennial rye grass.

It revealed that:

  • No single species scored highly on all of the evaluation criteria;
  • white clover in particular was outscored by other legume species on parameters such as early development and resistance to decomposition;
  • in comparison with the monocultures, the ASM showed increased ground cover, increased above-ground biomass and reduced weed biomass;
  • benefits with regards to productivity increased over time;
  • the stability of biomass production across sites was greater in the ASM than in the legume monocultures;
  • and ecological modelling revealed that the three best multifunctional mixtures all contained black medic, lucerne and red clover.

Click here to read more.

Species profiles



Clover in swards

  • For a successful clover-based ley, it needs to cover the ground quickly, establish well in a range of environmental conditions and be highly persistent until incorporation into the soil.
  • The optimum build up period for white clover swards is about three years.
  • Clover competes poorly with grass for soil nutrients and therefore needs a plentiful supply of nutrients when grown in a mixture.
  • Different percentages of clover in a sward can release varying amounts of N depending on the age of the ley and the method by which the clover is incorporated.

The pictures below depict the visual differences between swards with 15%, 25-30% and 50% coverage.

15% clover content

25-30% clover content

50% clover content

Images supplied by IBERS

Farmers who attended the British Grassland Society's Nutrient Wise Demos project have been able to view results of five different methods of incorporating white clover in to swards in order to reduce fertiliser applications, with 30% coverage being the desired outcome. For more information please click here.

What are farmers doing?

Farmers are increasingly looking to include forage legumes in fertility building mixes, i.e. lucerne, which produces large quantities of high quality feed.

In Europe, organic farmers most frequently use grass and clover mixes, the most popular being white and red clover (Trifolium repens and T. pratense), and perennial and Italian ryegrass (Lolium perenne and L. multiflorum). The potential for N fixation by these leys is high but the establishment can be under-par due to the cool, moist conditions required by the clover species.

The current practice of using mixtures of red or white clover and ryegrass can lead to a lack of synchronisation between the release of nutrients following incorporation of the green manure and the demands of the following crop.

To view comments from individual famers that highlight the different considerations when using mixed crops for fertility building click here.

Click here for a quick guide to help you choose the most appropriate green manure crop. (Taken from Sort Out Your Soil; A Practical Guide to Green Manures)


Advisory Leaflet - Soil Fertility Building Crops in Organic Farming

Defra Project OF0316 - A review of leguminous fertility building crops with particular reference to Nitrogen fixation and utilisation

Using legume-based mixtures to enhance the nitrogen use efficiency and economic viability of cropping systems

Sort Out Your Soil; A Practical Guide to Green Manures

To find out more about the advantages and disadvantages of the main legume species please click here.

Considering your options for grassland reseeding? Click here to read the Nutrient Wise Demo Factsheet.

Record requirements

Where appropriate you should have already:

  • Recorded farm size
  • Started keeping records of livestock numbers
  • Any imports or exports of manure or slurry on or off your farm
  • The dates and locations of any field sites used for the storage of FYM
  • Calculated manure storage capacity
  • Completed a risk map

Annual Dates you need to know

Organic manure N field limit

  • Limit of 250kg N/ ha in 12 months
  • Only applied to livestock manure spread to land and other organic manures such as sewage sludge, compost or abattoir waste
  • PAS100 green composts will be changed to 1000kg N/ha over 4 years in specified circumstances (i.e. top fruit orchard) when applied as mulch, 500kg N/ha every two years when worked into the soil. Such applications still count towards the 250kg N/ha/12 month limit

Please click here to find out application rates or N content of other manure types, or click here to read more about field applications.

Livestock manure N farm limit

  • Limit of 170kg N/ha per calendar year
  • Only applies to manure from pigs, cattle, sheep, goats, deer, horses, and poultry
  • A derogation to 250kg N /ha can be applied for on farms with grazing livestock and at least 80% grassland
  • For more information please click here.

Storage and spreading of organic manures

  • Only high readily available N livestock manures need to be stored (such as slurry and poultry manure, not FYM)
  • 5 months storage for cattle (Oct-Feb)
  • 6 months storage for pigs and poultry (Oct-Mar)
  • Do not spread:
    • within 50m of a spring or borehole
    • within 10m* of a watercourse or ditch (* can be reduced to 6m if using precision application equipment)
    • on waterlogged, frozen, snow covered or flooded land
  • Avoid spreading if there is a risk of pollution. Think about slope, ground cover, weather, soil type and land drains. Refer to your risk map

For more information on storage please click here, and for spreading click here.

Closed periods for spreading

Closed periods for high readily available N organic manures

Closed periods for manufactured N fertiliser

Crops to which manufactured N can be applied in the closed period

N Max limits

  • only applied to N from manufactured fertiliser and crop-available N from livestock manure

For more information please click here.

Does my Slurry Store need planning permission?

Created by Susan Watters, Development Manager (West) Cornwall Council Planning.

Does my Slurry Store need planning permission?

Fertiliser Value

  • Fertiliser value of manures is influenced by manure type, DM content, application timing and technique, soil type and weather patterns
  • These factors will also influence N availability to the next crop grown
  • Cultivation using discs and tines is less likely to be effective than ploughing in minimising ammonia losses

Soil mineral N

  • When there is uncertainty about the level of residual mineral N present in the soil such as following long term manure use of where manures have been applied at unknown rates, sampling for soil mineral N (SMN) is recommended
  • SMN results will enable top up inorganic fertiliser N additions to be calculated for the next crop grown

Phosphate and potash

  • Manures are valuable sources of plant available P and K although short term availability can be lower than from water soluble P and K fertilisers
  • Where crop responses to P and K are expected or when responsive crops such as potatoes are grown, the available P and K content of the manure should be used to estimate manure P and K supply and any additional need for inorganic P and K fertiliser additions
  • Where P and K applications are for the maintenance of soil reserves, the total P and K content of the manure should be used. For most arable crops, typical manure application rates will supply all the P and K the crop needs
  • Over the crop rotation, manure P and K should be considered the same as inorganic P and K fertiliser in balance sheet calculations
  • At soil P index 3 or above, care is needed to ensure that the total phosphate inputs in organic manures do not exceed that removed in crops during the rotation

Key messages

  • Know the nutrient content of applied manures
  • Apply manures evenly at known rates
  • Rapidly incorporate manures, where appropriate or use an application technique that will minimise ammonia losses
  • Apply manures in spring where possible to reduce nitrate leaching losses
  • Take the nutrient supply from manures into account when calculating inorganic fertiliser additions

What are farmers doing?

  • Around 62% of holdings have a nutrient management plan (compared to 55% in 2009)
  • In 2011 23% of nutrient management plans were created by the farmer without professional advice, 49% were created between the farmer and a professional advisor, and 27% were created solely by a consultant. Of those who consulted someone, in 80% of cases advice was sought from fertiliser advisors or agronomists
  • Of those who have had a Nutrient Management Plan, 43% have seen a financial benefit, while 30% have seen an environmental benefit
  • 67% of holdings have a Nutrient Management Plan for their farm, a similar percentage to that seen in 2009. 65% of holdings update this every year
  • Over half of holdings calculate nutrient content of manure, whilst 22% test nutrient content by taking samples. 70% of holdings test the nutrient content of their soil regularly (at least every 5 years)
  • The region with the highest proportion of farmers who have plans is the East of England and the lowest proportion of holdings is the North East region
  • Taken from Defra Farm Practises Survey results source - http://www.defra.gov.uk/statistics/files/defra-stats-foodfarm-environ-fps-FPS2011-110801.pdf

What are farmers doing?

  • 83% of holdings spreading N based fertiliser on grassland or crops own at least 1 fertiliser spreader others use contractors
  • The Average age of fertiliser spreaders is 8 years old
  • Half of holdings gave their spreader a general check more than once a year
  • 27% check and calibrate the spread pattern of the spreader more than once a year, 56% check and correct for fertiliser type more than once per year
  • Grassland 52% of holdings spread their own fertiliser with 12% spread by contractor, and 37% spreading none at all. In arable systems 48% of holdings had fertiliser spreaders, 13% used contractors and 39% were not spreading fertiliser
  • Taken from Defra Farm Practises Survey results source - http://www.defra.gov.uk/statistics/files/defra-stats-foodfarm-environ-fps-FPS2011-110801.pdf

What are farmers doing?

  • Two thirds of farmers can store solid manure in temporary heaps in fields while almost half have storage facilities for solid manure on a solid base
  • Most popular storage facility for slurry is the tank with 18% of holdings having these stores
  • Of those who have facilities to store manure of slurry, no more than 15% of these are covered
  • Average age of storage facilities is 15 years old
  • Approximately 14% of farmers plan to enlarge, upgrade or reconstruct their storage facilities and of these 42% plan to make these changes in the next 12 months
  • 3% of farms have a slurry separator
  • 14% export manure or slurry off their farm (of which 89% is manure to a neighbouring farm and 16% export slurry to neighbouring farms.
  • Taken from Defra Farm Practises Survey results source - http://www.defra.gov.uk/statistics/files/defra-stats-foodfarm-environ-fps-FPS2011-110801.pdf

Cattle slurry

Cattle slurry

Cattle slurry

Pig Slurry

Pig Slurry

Pig Slurry

Cattle Slurry

Cattle Slurry

Cattle Slurry

Pig Slurry

Pig Slurry

Pig Slurry

Pig Slurry


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The NVZ regulations form part of the Nitrates Directive, an EC law aimed at reducing the amount of N entering the watercourse as a result of agricultural related operations. Certain farming operations on livestock farms within the designated NVZ areas will be governed by the regulations. These include being able to demonstrate adequate slurry storage capacity relative to livestock enterprise size and type and restrictions over the times of year when slurry and farm animal waste can be applied to land.

For more information on NVZs and to download good practice guides please click here, or to complete the NVZ self assessment tool to assess your farming practises against the requirements of legislation please click here.

Catchment Sensitive Farming

CSF aims to reduce the level of diffuse pollution in rivers, groundwater, and other aquatic habitats caused by farming operations. Catchment Sensitive Farming delivers practical solutions and targeted support to enable farmers and land managers to take voluntary actions to reduce diffuse water pollution from agriculture to protect water bodies and the environment.

For more information on the grant scheme, events, guidance notes, and locations of catchments please click here, or if you are in a catchment and you would like to contact your local officer, please click here.

Soils for Profit

The Soils for Profit project looks at delivering on farm practical advice to help farmers make the most of their manures and nutrients. If you are interested in receiving a free visit please visit the Soils for Profit page.

Tried and Tested

The Tried and Tested Nutrient Management Plan helps make nutrient management planning and recording practical and simple for your farm. The system deals with planning fertiliser and manure use, meeting regulatory demands and protecting the environment.

For more information please click here.

RB209 The Fertiliser Manual

Using the fertiliser manual will help farmers and land managers better assess fertiliser requirements for the range of crops grown by suggesting what level of nutrients are required to provide the best financial return for the farm business.

To access RB209 please click here.


A nutrient management software tool that is freely available for farmers to use. It allows for field level record keeping, recommendations allowing for organic manure nutrients, and nutrient application plans.

To access PLANET please click here.


Organic manures are a valuable source of plant available nitrogen (N). However, using either too much or too little N can adversely affect crop yields and quality. By integrating manure and inorganic fertiliser N additions, crop yields and quality will be optimised and pollution risks reduced.

MANNER is a decision support system that can be used to accurately predict the fertiliser nitrogen value of organic manures on a field specific basis. MANNER has been developed using results from the latest research, funded by DEFRA, on organic manure utilisation on agricultural land.

To access MANNER please click here.

Slurry Storage

For regulations on slurry storage developed by the Environment Agency, including the capacity, design and construction requirements and good practise guidelines please click here.

For information on the regulations concerning spreading slurries and manures on land please click here.

Slurry Wizard

Developed by Dairy Co, the main aim of the Slurry Wizard is to identify whether there is adequate slurry storage and to allow for different strategies to be explored.

The wizard has three key components; to calculate the existing slurry capacity; to calculate the existing slurry production; and the production of a report to look at the monthly production compared to the existing storage.

For more information or to order your copy please click here.

Water Framework Directive

The Water Framework Directive came into force in Decemer 2000 and became part of EU law in Dec 2003. It claims to protect and enhance the quality of surface freshwater, ground waters, groundwater dependent ecosystems, estuaries and coastal waters out to one mile from low water. For more information on the Water Framework Directive from the Environment Agency, please click here.

Water notes are intended to give an introduction and overview of key aspects of implementation of the Water Framework Directive.