Diverse roots revealed at cover crop champion site in Essex

Our first post-emergence video shows clear evidence of diverse rooting of a multi-species cover crop mix at a farm site in Essex.

The farm in East Anglia is one in a network of eight cover crop champions set up by AHDB Cereals & Oilseeds to provide practical case studies on the impact of cover crop approaches.

Following on-farm trial design principles, each of the champions has established a cover crop ahead of various cash crops for harvest 2025.

Jonathan and Jane Clarke’s farm (Bury Farm) is in Great Canfield, Essex.

Trial approach

The farm’s rotation provides plenty of opportunities for short-term cover ahead of spring crops.

As cover crops are only being grown on the farm for the second time, they are still experimenting to identify what works best in their system. This year, the Clarkes are testing three establishment techniques:

1. Direct drilled into stubble.
2. Broadcast followed by harrowing over the top (lightly scratching under the stubble).
3. Broadcast with a light cultivation.

They have opted for a six species cover crop mix that contains buckwheat, crimson clover, hairy vetch, linseed, phacelia and a specialist fodder radish (Smart Radish).

The cover crops were sown in late August, with the plants established via broadcast methods slower to get going, due to poorer seed-to-soil contact.

Early assessments

Harry Moffat, from Oakbank Game & Conservation Ltd (which part-funded the trial), dug up samples on 4 October and placed them side by side (on a spade) to reveal the rooting characteristics:

• The buckwheat was already going deep
• The radish had long, thick roots
• The linseed had long, thin roots
• The vetch had many thin roots, which were reluctant to let go of the soil
• The phacelia was just getting going

At the time of assessment, clover was sparse, with no good samples available for sampling.

Interestingly, the most impressive roots were from volunteer borage. Borage was cropped in the field two years ago, with its offspring taking up residence in the field’s seedbank.

Compared to the cover crops, it had a head start and featured the thickest roots of the bunch. Jonathan isn’t too concerned as it all adds roots to the mix and it should be knocked back by the first hard frosts.

Although not unexpected, where the land was lightly cultivated, borage’s growth was clearly subdued – unlike where the cover crop was direct drilled into the stubble of the previous crop, where borage was already waist height.

The presence of diverse roots should help maximise the benefits of the cover. For example, it will improve the overall structure of the soil and mine nutrients deep within the soil profile. The legumes will also fix nitrogen (with nodulation already visible on the vetch).

The buckwheat is already flowering, which is offering something for the pollinators too. Once again, it should break down at the first good frost.

We will now assess the development of the cover crop’s biomass before terminating it and establishing a spring cereal crop next year.

Cover crop roots on display

Above: Plants from the cover crop trial field in Essex showing diverse rooting characteristics. Left to right: volunteer borage, radish, linseed, phacelia, vetch and buckwheat.

Unlike the other crop crop champions, Anthony is using more year-round cover crops. The soil is mainly very heavy Wealden clay, which can go from too wet to too dry quickly. He uses diverse cover to improve the soil’s resilience, with long tap roots helping to break soil pans naturally.

Ready for bed? Need something to send you off? Try my latest instalment of the @TheAHDB cover crop trial I’m running… guaranteed to have your eye shut in seconds. Unless like me and @cereals_se you really like the role cover crops can play in making your soil a better place for… pic.twitter.com/zxp89DUIto

— AnthonyBecvar (@anthonybecvar) November 13, 2024

About the cover crop champions

First pioneered in the USA, cover crop champions tackle the complexity associated with cover cropping and share their experiences with other farmers.

Supported by AHDB, the champions will record core measurements and observations to help assess the impact of their varied approaches.

We plan to release post-establishment updates for all champions over the next few weeks.

You can follow their journeys on the cover crop champions web page.