Cover Crops for SFI (CSAM2)

What is a Cover Crop?

Cover crops are essentially non-cash crops that are grown to cover bare soil or stubbles between the harvest and establishment of main food crops. They are usually grown over a single winter, although in reality, the duration of the cover can last from a few weeks to months or even years depending on the objective of growing the crop and the plant variety.

Cover crops are so called because they are used to cover the soil between the main crop rotations.

The Advantages of Cover Crops

Cover crops can provide a range of advantages depending on what plant varieties you decide to sow, including reducing erosion, improving soil fertility and health, improving water retention, managing pests and diseases, increasing biodiversity, sequestering carbon, and reducing nutrient leaching.

Often, however, the precise mix of plants, and therefore economic and environmental benefits realised, will depend on what works with your standard farm practice, machinery, crop rotation, and soils.

Cover crop varieties fall into four main groups – legumes, cereals and grasses, brassicas and herbs – all of which have different impacts on your soil.

Legumes, for example, fix atmospheric nitrogen and add it to the soil, lessening the need to add inorganic fertiliser. They also attract beneficial pollinators, help control soil erosion, and increase soil organic matter.

Cereals and grasses can develop extensive root systems that scavenge soil nutrients and can deliver this nutrients to future crops once killed off. They also produce significant amounts of biomass, which means they add organic matter to soil, and they suppress weeds.

Brassicas are used to provide winter or rotational cover between vegetable and speciality crops. They are effective at breaking up soil compaction and suppressing weeds, and can double up as winter livestock fodder.

Herbs are excellent for cover cropping when there is a need to avoid rotational conflicts because they are unlikely to be related to any cash crop.

Common Cover Crops

There are a huge number of different cover crop varieties that make up the four categories listed above. Some of the most popular planted in the UK include:

• Buckwheat

  Buckwheat is favoured for its speedy growth – its seeds germinate just three to five days after sowing and leaves of up to three inches wide can develop is as little as a fortnight – as well as its weed suppressant qualities and its ability to scavenge phosphorus that would otherwise by unusable by subsequent crops.

  Buckwheat has a range of other advantages also; its roots leave topsoil loose and friable, it attracts pollinators and other useful insects, and it also requires light management.

  However, disadvantages include it is not frost or drought tolerant and it wilts under a hot sun.

• Mustard

  Mustard is another popular common cover crop for a number of good reasons. It is quick-growing, flowering in four to six weeks and reaching full maturity in 10 weeks.

  It produces large amounts of biomass, enabling it to sequester atmospheric carbon, and crucially, it holds nitrogen well, making it available to future crops and cutting the need for inorganic nitrogen applications.

  Although more frost-tolerant than buckwheat, mustard leaves begin to break down after a few mild frosts. It is also susceptible to flea beetle if sown in spring and like all brassicas, can suffer significant pigeon damage.

• Kale

  Kale is an excellent winter cover crop because of its hardiness and ability to withstand cold and frost. It is also high in protein, making it an excellent fodder crop for sheep and cattle.

  From a soil perspective, kale scavenges excess nitrogen, phosphorus and calcium from the soil to make it available to future crops, and its roots break up the top soil and protect it from erosion.

  Due to its leafy canopy, kale is also an excellent weed suppressor.

• Linseed

  Linseed, also known as flax, is a popular choice of spring-sown cover crops due to its ability to fight soil compaction and because it performs well in drought conditions.

  The plant’s root structure also means it is effective at preventing soil erosion and the leaching of key nutrients from a field.

  As well as a cover crop, flax is also popular as a game crop, and over-winter wild bird seed crop, and as an arable break crop to help control weed such as blackgrass.

• Phacelia

  Phacelia is another popular cover crop due to its ability to stabilise soils, and because it is can be withstand a broad range of pHs, from 6.4 to 8.6.

  It is known for its fast establishment, ability to suppress weeds, prevention of nitrogen leaching, and for its shallow root structure which is highly effective at conditioning the top three to four centimetres of soil.

  It produces eye-catching purple flowers, which are also very effective at attracting pollinators and other useful insects.

• Vetch

  As a legume, vetch is favoured for its nitrogen-fixing abilities which it then makes available for future crops.

  It is an excellent weed suppressor that produces a lot of above-ground biomass, sequestering large quantities of atmospheric carbon in the process. This can be grazed or used as mulch or compost.

  Its extensive root system prevents nutrient leaching and soil erosion.

  In the UK, vetch is generally considered a spring crop, but some varieties such as hairy vetch can be used as a winter cover crop.
  
  
  

Cover Crops and SFI

Unsurprisingly given the environmental benefits cover crops can achieve, there are a number of SFI actions dedicated to growing them. These include:

• SAM2/CSAM2
• SOH2
• SOH3

SAM2/CSAM2

SAM2/CSAM2 is listed under the soil health SFI actions and consists of growing a multi-species winter cover crop. The action attracts a payment of £129 per hectare and lasts for a duration of three years.

To qualify, the crop must be established in the winter months (December, January and February), must be sown and must include a minimum of two plant species from two of the plant families brassicas, legumes, cereals and grasses, and herbs.

This action is both rotational and static, meaning its location can be moved for the second or third years of the SFI agreement, or it can remain in the same place for each of the three years.

SOH2

SOH2 is the spring cover crop version of CSAM2, although it attracts a higher payment of £163 per hectare.

As per CSAM2, it lasts for three years, is rotational and static, and must include a minimum of two species from plants from the four plant families.

However, in the case of SOH2, grasses can only make up a maximum of 25% of the seed mix by weight.

Cover crops grown under SOH2 must be established in the spring months (March, April and May).

SOH3

SOH3 is the action of growing a multi-species summer cover crop, established in June, July, or August.

Unlike CSAM2 and SOH2, SOH3 requires you to use a rapid-growing seed mix with at least four different species of plant from two or more of the four plant families.

As with SOH2, under SO H3 grass varieties must make up a maximum of 25% of the seed mix by weight.

SOH3 attracts a payment of £163 per hectare and has a duration of three years.

Cover Cropping Through the Seasons

As the SFI actions demonstrate, cover cropping takes place throughout the year. But what is the best season to plant cover crops, and what are the benefits of cover cropping at different times of year?

Spring Cover Cropping

Cover crops grown at any time of the year result in a number of benefits including reduced soil erosion, nutrient leaching, better water filtration and retention, better soil structure and increased organic matter, reduced compaction, weed, pest, and disease management, and a host of other gains.

But growing them at certain times of the year can add extra benefits to your farm.

Spring cover cropping, for example, is an excellent way to improve or restore land after a difficult and wet winter, where winter crops have failed and establishing combinable spring crops is impossible.

Sowing cover crops in these circumstances can help absorb excess moisture from the land, restore the land in time for autumn drilling, help control weeds such as blackgrass, catch and fix nitrogen into the soil, add organic matter and ultimately give soil the lift it needs to produce profitable cash crops later in the year.

Summer Cover Cropping

Summer cover crops benefit from long hours of daylight and (usually) sunlight and warmth. As a result, they grow quickly, sequestering large amounts of atmospheric carbon which boosts soil organic matter.

This, in turn, improves soil structure, increases water filtration and holding capacity, nutrient holding capacity, and increases beneficial earth worms and soil microbes.

However, where summer cover crops have the potential to show particular value is in combatting soil erosion. Summer is generally the driest season of the year when bare top soil can easily be eroded by the wind. Flashing flooding and weather events that have become more frequent over recent years also take their toll.

A summer cover crop will prevent much of this, leaving your all important top soil where it should be – on your field.

Winter Cover Cropping

Winter cover cropping is largely about protecting your soil from the harshest elements of the weather. Having a roots in the soil at this time of year helps fix the top soil in place and reduce erosion either from strong winds or from rain water run-off. This in turn reduces nutrient leaching from the soil.

The improved soil structure that results from cover cropping also helps the soil to absorb and hold water more effectively, leading to less flooding or waterlogged fields.

Another major advantage of winter cover crops is that they can be grazed by out-wintered livestock as part of an integrated farm management approach, which means as well as creating agronomic benefits, winter cover crops can also lead to favourable economic outcomes.

Summary

Cover cropping is growing in popularity as a way of protecting and regenerating soil, managing pests, weeds, and diseases, and reducing the amount of crop inputs needed to realise the same cash crop yield and quality.

So effect are they are achieving these aims, cover cropping has been recognised in the Sustainable Farming Incentive (SFI) scheme, with three SFI actions having been dedicated to it.

Including these actions in your SFI agreement would mean getting paid for generating significant improvement in your farm’s soils, which in turn will benefit all future farming activities, including your bottom line.