Are Cover Crops Worth It? Thoughtful Choices Deliver Returns

You can hardly go to an arable farming event without hearing about "cover crops" and "catch crops". But are they worth the space, time and investment?

Cards on the table, I am a fan. Having been part of the journey on the farm at home - from tentatively trying them years ago, to confidently increasing the coverage to 32% of the arable land this year, - I can say from experience that, when used properly and in the right context, they can really deliver for soil, biodiversity, water and the farm's bottom line.

They won’t transform your farm overnight, but some benefits (e.g. improved soil structure) can be observed after just a few weeks. And, to my mind at least, given the increasing volatility of our weather - I would rather have living plants in the soil at all times than not. On our farm, we view them as an insurance policy.

As with any other crop, there are pitfalls to navigate of course - Toby Simpson put it well in his Nuffield report on cover cropping opportunities in UK agriculture:

Cover crops can be everything and nothing.

Integrated thoughtfully, they can be everything - improve your soil, support your rotation, help cut costs and set you up for long-term success. Knowing what your aims are, and what you are looking for, is very important from the outset, and crucial to ensuring that your cover crops don't turn out to be nothing, or ever worse - negatively impact the following crops in the rotation.

What are the benefits of cover crops? A run-down.

Here’s what the evidence, and experience, tells us they can achieve:

1. Protect soil from weather erosion and heat

Bare soil is vulnerable. Rainfall alone can cause significant particulate erosion, washing away valuable topsoil, nutrients and contaminants into waterways. A well-chosen cover crop canopy shields the soil from heat, wind and rain, holding it where it belongs.

By introducing living roots into the soil shortly after harvesting a cash crop, cover crops continue to feed soil biology through the secretion of root exudates, maintaining soil function when it would otherwise be exposed to the elements.

Soil cover of 30% can reduce run-off by 50% and erosion by up to 80% (AHDB), although careful species selection is key to maximising the benefit.

SARE and the University of Missouri compiled studies that showed, on average, reduction in soil erosion from cover cropping of 20.8 t/acre on conventionally tilled fields, 6.5 t/acre on reduced-till fields and 1.2 t/acre on no-till fields.

If we do a better job of keeping all the soil in the field it started in, that will be a big step forward.

2. Improve water infiltration and soil structure

The root network of a diverse cover crop opens up the soil, improving porosity and helping air and water move through the profile. This also helps to alleviate surface compaction.

Root systems create channels that allow water to infiltrate deeply into the soil, where it can be stored for long periods and eventually replenish groundwater reserves. Poorly structured soils often lead to rapid surface runoff, reducing water reserves during dry periods and lowering water use efficiency. In contrast, well-structured soils, reinforced by cover crops, are less prone to erosion, which is particularly important on sloped land or during periods of prolonged wet weather. Improved water infiltration reduces pesticide and nutrient leaching, which can cause significant water pollution in poorly structured, bare soils.

3. Capture, retain and mobilise nutrients

Cover crops trap residual nitrogen and other nutrients, reducing leaching. Some species are especially effective at scavenging and mobilising nutrients, such as soil phosphorus (P) in forms with low bioavailability, which are then released when the cover crop is terminated. Buckwheat is one that's often talked about, but there are several others. And, of course, legumes fix nitrogen, accelerating residue mineralisation and benefiting subsequent crops.

Overwinter cover crops significantly reduce nitrate leaching compared to bare stubble, especially where species like oil radish are included.

Perhaps more importantly, destruction method and timing play a major role in how much nitrogen becomes available for the next crop.

In the Nitrogen Release from Cover Crops (NiCCs) projects, led by ADAS, chemical termination with glyphosate was consistently shown to improve spring nitrogen availability compared to mechanical destruction (such as rolling on a frost or mowing and incorporation). Trials also found that early termination in January increased the risk of nitrate loss due to the breakdown of residues and lack of ground cover. The best results came from chemical termination in late February, which led to the highest yields in a following spring oat crop - while also allowing growers to reduce nitrogen inputs by around 30 kg/ha without impacting yield.

This doesn't mean that late February destruction is always the right thing to do and guarantees higher yields - if only such simple prescriptions were possible in farming! - but trials such as these do illustrate what is possible, given careful management.

🧠 Did you know? A number of studies report that the majority of cover crop nitrogen is released within days of destruction.

While the amount made available to the following crop varies widely (anywhere from 0 to 120kg N/ha, depending on species, weather, and termination), the figure which appears most commonly observed is around 30kg N/ha.

4. Suppress weeds and pests

Fast-growing mixes shade out weeds and compete for space and resources, reducing pressure later. Some species also exhibit allelopathic properties and others have been used to suppress nematodes, but get in touch if you require guidance.

5. Build biomass, soil organic matter and support carbon sequestration

Green biomass returns organic matter to the soil, feeding microbial life and building long-term resilience. Greater diversity in the soil biota improves function and carbon cycling.

Evidence suggests that more active soil biology and increased necromass contribute to higher soil carbon levels over time (Poeplau & Don (2015) found consistent increases in soil organic carbon from cover crop use.)

6. Provide forage and habitat

Livestock grazing on cover crops can offset costs while improving soil health, although it's essential to assess nutrient loss and soil compaction risks, grazing timings and species composition carefully.

For example, Smart Radish is a unique type of forage radish that has been bred specifically for forage and soil health. It produces significantly more palatable forage in the same time period as alternative radishes and makes a very good substitute for turnips, etc. in a slightly later sowing slot.

Flowering species like phacelia, buckwheat and vetch benefit pollinators, farmland birds and mammals. However, some species, are not compatible with grazing. If you are planning to graze cover crops you haven’t used before, or you are not sure about compatibility or how species or growing conditions might affect forage quality, give us a call.

🐑 Our Smart Graze cover crop seed mix and the Soils and Stock grazing cover crop mix are especially formulated for mixed farming systems, and can be extended with additional straights to suit your particular requirements and soil type.

---

Case study: grazing cover crops boosts resilience in Kent

Harry Moffat visited a friend farming in Kent, where the family has started planning for greater farm resilience. They’ve been using strip tillage for 15 years but never felt the need to try cover cropping... until now. With George preparing to return home to eventually take over the day-to-day running of the business, he began exploring diversification options.

Through his father’s involvement in a farm cluster and a Landscape Recovery pilot, George became aware that grant funding might be available to help establish a cattle herd. That, in turn, led him to trial cover crops for the first time.

They planted the Oakbank Soils and Stock winter cover crop seed mix, which has delivered dual benefits - providing fodder for the cattle and improving soil structure. This seven-species mix includes black oats, crimson clover, forage rape, forage rye, spring vetch, stubble turnip and sunflower. The diversity of species ensures a variety of root systems working together: some rooting shallowly to stabilise the surface, and others growing deeper to open up the soil.

A multi-species mix also offers insurance - if one species fails, others can take up the slack. That’s exactly what George found. In some areas, the stubble turnips struggled, likely due to flea beetle or unfavourable growing conditions, but the kale rape and forage rye established well, delivering ground cover and grazing for the herd.

Biomass is critical for fodder and walking the fields showed just how important establishment timing is. Of two adjacent fields, drilled just a week apart in mid to late-August, we found almost half the biomass in the later-drilled field. A valuable lesson: drill cover crops as early as possible to maximise growth and return on investment.

---

Why quality and advice matter

There is no “one-size-fits-all” approach to cover cropping and not all cover crops are created equal. To get meaningful results, you need the right mix of species and cultivars for your soils, climate, rotation and goals, backed by agronomic expertise and up-to-date breeding and research. A “cheap and cheerful” mix chosen without thought often delivers poor establishment, weak biomass and limited benefits.

Understand your context

What are your objectives? Grazing, carbon capture, ecosystem services and/or nutrient efficiency.

Species and variety selection

Diversity is key, but not all varieties are equal.

What are your weed and disease profile, rotation and agronomic limitations?

Establishment, management and termination

Getting all three right is key to realising the benefits of cover crops.

What about the economics?

Some benefits, like improved soil structure, become visible quickly. Others, like improved organic matter and resilience, take time. You may not see immediate financial returns, which is why schemes like SFI and private initiatives (e.g. LENS, Soil Association Exchange and water company funding) can help support the transition.

Recent research results from the NiCCs project demonstrated that with SFI funding (e.g. CSAM1) factored in, a late-destruction approach to cover crops enabled a confident reduction in N fertiliser in the following crop and improved net margins by up to 25%, fully offsetting the cost of growing the cover.

With livestock, extending forage availability and potentially improving its quality through grazing of cover crops in the arable rotation can lead to relatively quick returns, both in terms of liveweight gains and reducing the need for supplementary feeding. It can also be a good way of "trying out" the concept of incorporating a herbal ley, without the longer time commitment.

A healthy soil is a business asset. The direction of travel is clear: as farmers, we are being paid for public goods like clean water, carbon storage and biodiversity - and cover crops are a proven way to deliver these outcomes cost-effectively while increasing business resilience.

Start small, but start

Cover crops won’t suit every field, every year. But introducing more diversity into your rotation is no longer just desirable, it’s essential. Cover crops offer a low-cost way to begin, without drastic changes to your system.

Start small, monitor results, and build confidence. Our experience is that farmers who start with a trial often expand year on year as they see tangible improvements: better structure, more earthworms, reduced waterlogging and compaction, and healthier soils overall.

Speak to the experts

If you’re considering cover crops, short-term summer catch crops, or multi-year herbal leys, talk to our team. We’ll help you:

• Choose the right cover crop mix of species and cultivars for your system

• Design a quality mix that delivers measurable benefits

• Make the most of funding options to offset costs

📞 Call us on 01480 890686 or speak to your advisor today.