Updating guidance on cover crops (scoping review)

1. Introduction

This document is an invitation to participate in a request for quotation for a scoping review to update AHDB guidance on cover crops.  Submissions should be based on the information contained within this document and in the format outlined in section 5.  Deadlines and submission instructions are contained in section 7.

2. Background

Cover crops are grown for a variety of reasons, and the use of cover crops is widespread on arable cropping farms (Storr et al, 2019; Magistrali et al, 2022). The Sustainable Farming Incentive (SFI) scheme includes several actions for the use of multi-species cover crops and it is likely that the use of cover crops will continue to increase in the UK.

The SFI scheme includes:

• Multi-species winter cover crop (SAM2: https://www.gov.uk/government/publications/sfi-handbook-for-the-sfi-2023-offer CSAM2: https://www.gov.uk/find-funding-for-land-or-farms/csam2-multi-species-winter-cover-crop) which are well established over the winter months and present between harvesting a cash crop and establishing the next cash crop.
• Multi-species spring-sown cover crop (SOH2 SOH2: Multi-species spring-sown cover crop - GOV.UK (www.gov.uk)) which are established in the spring months (usually between March and May) after a cash crop or winter cover crop until the next cash crop is grown. But it must not be harvested as a ‘cash crop’.
• Multi-species summer-sown cover crop (SOH3: SOH3: Multi-species summer-sown cover crop - GOV.UK (www.gov.uk)) which are established in the summer months (usually between June and August) after harvesting a cash crop and before the next cash crop is sown or a winter cover crop is sown.

AHDB provides information on cover crops on its website (An introduction to cover crops | AHDB) and curates the ‘Cover Crops Guide’ platform, which was developed in partnership with the Farmer Scientist Network, David Purdy Soils, Kings Crops / Frontier, Newcastle University and UK farmers.

As well as providing information online, AHDB’s Strategic Farm and Monitor Farm network has explored the use of cover crops in a variety of situations on-farm, disseminating knowledge more widely at events. For example, see How Strategic Cereal Farms evaluate cover crops | AHDB

However, there remains a need for updated and independent information on cover crops. AHDB Cereals & Oilseeds is commissioning a scoping review to update the guidance that is available to UK farmers, specifically focussing on cover crop destruction and the long-term soil health benefits of using cover crops. The findings of the scoping review will be used to update AHDB guidance and information.

3. Service requirement

The scoping review requirements are split into two parts: 1) cover crop destruction, and 2) long-term soil health benefits of using cover crops. Further details are provided below.  The two parts should be costed separately and delivered as two separate review documents.  If there is strong justification for delivery as a single review, please explain this in your bid.  Note that a single supplier is required to deliver both parts.  An indicative budget to cover both parts of the requirement is provided in section 4.

The scoping review(s) should collate evidence from published research and grey literature, building on existing information provided by AHDB and the ‘Cover Crops Guide’.  The focus should be on UK arable cropping systems (including grazing cover crops) and temperate climates as far as possible, and include UK case studies as appropriate.

1) Cover crop destruction

Timely and effective termination of cover crops is critical for preventing competition with the following crops, limiting carry-over of cover crop species as weeds in the following cash crop, and managing nutrient dynamics (e.g. lock up).

This part of the scoping review should include:

• Information relevant to winter cover crops, spring-sown cover crops, and summer-sown cover crops.
• Cover crop destruction methods
  • Detail on the ease of termination, and/or challenges, associated with specific cover crop types, according to destruction method
  • Impact on following crop establishment - or other issues arising – according to cover crop destruction method
  • Impact on following crop establishment - other issues arising – according to timing of cover crop destruction
  • Influence of soil types on cover crop destruction (timing and method), and establishment of the following crop
• Challenges of breakdown of biomass when destroying cover crops
• Cover crops becoming a weed burden in the following crop, highlighting specific cover crop species and in which crop they can be an issue
• Summary of findings presented in practical terms to update existing AHDB guidance on cover crop destruction
• Knowledge gaps and recommendations for further research

Out of scope of the cover crop destruction review:

• Cover crops as a green bridge for pests and disease
• Cover crops for biofumigation
• Information on cover crop species/types, for example pros and cons of growing them, other than outlined above

2) Long-term soil health benefits of growing cover crops

Cover crops are grown for a variety of reasons, but the long-term impact of their use on soil health is equivocal. This may be due to a lack of data collected on-farm, as well as site-specific responses to growing cover crops.  However, long-term research and demonstration platforms in the UK have included cover crops as part of an arable rotation - these studies are a valuable source of information that can be used to update guidance for wider uptake. In the context of this scoping review, soil health benefits include improvements to soil structure, water infiltration, drainage, soil biodiversity and functioning, and increased levels of soil organic matter.  

This part of the scoping review should include:

• Information relevant to winter cover crops, spring-sown cover crops, and summer-sown cover crops.
• Information relevant to cover crops grown more than once in a rotation
• Findings from long-term UK experiments where cover cropping has been used as part of the system and soil health indicators have been measured (for example, indicators that are used in the AHDB soil health scorecard: The soil health scorecard | AHDB)
• Findings from on-farm or academic research where cover crops have been grown repeatedly (on a rotational basis) and soil health indicators have been measured
• Which cover crop species impact on soil biodiversity, including changes to beneficial soil biology and plant pathogens
• Evidence on the rotational impacts of different cover crops species or mixtures, where soil health has been measured in some way
• Summary of findings presented in practical terms to update existing AHDB guidance on long-term soil health benefits
• Knowledge gaps and recommendations for further research

Out of scope of the review on long-term soil health benefits of cover crops:

• Yield benefits
• Establishment and destruction methods
• Nutrient release to following crop

4. Budget

The maximum budget for delivery of both parts of this work is £30,000 (inclusive of VAT).  

5. Structure/format of submission

There is no specific application form required for your submission.

You may use the AHDB R&KE full proposal form if you wish, but note that the scoring criteria for this request for quotation is different to the one outlined in the AHDB R&KE full proposal form: AHDBResearchApplicationForm-FullProposalSmall - Amended April 2023.docx (live.com).

An evaluation panel will assess submissions in line with the scoring criteria and weightings in section 6 to decide the best outcome for these services.

Your quote should include:

• How you intend to address the project objectives and deliverables.
• Timelines and milestones, including a start-up discussion meeting and a review discussion following delivery of a draft review with AHDB.
• Details and the capabilities of the team that will complete the work.
• Details of any subcontractors/other organisations you will work with to achieve deliverables.
• Evidence you or your team have completed similar or related work.
• Proposed budget, including a breakdown of payment schedule expectations.
• Your contact details.

Joint applications from two or more organisations are acceptable and encouraged where there is added value. AHDB reserves the right to not proceed with any application or, if appropriate, to request applicants to form a consortium to work together to deliver a programme of activities.

6. Evaluation and award of contract

Evaluation of tenders will be on the following basis:

Bids will be scored against the criteria shown in the table below (continued overleaf):

7. Tender submissions

Submissions to be made electronically:

Submissions will remain unopened until after the closing date and time has passed

8. Timetable

Please note these timescales are approximate and may change.

A project initiation meeting will be held between the successful bidder and AHDB at the commencement of the contract.  Additional meetings will be held as required for progress updates.

9. Terms/conditions of participation

AHDB Terms and Conditions for the supply of goods and services shall apply to any contract awarded as a result of this request for quote.

If you have any questions relating to this tender please contact:

Annex – AHDB resources and links

Previous research funded by AHDB on cover crops includes the following:

A review of the benefits, optimal crop management practices and knowledge gaps associated with different cover crop species | AHDB

Maximising the benefits from cover crops through species selection and crop management (Maxi-Cover crop) | AHDB

Fostering populations of arbuscular mycorrhizal (AM) fungi through cover crop choices and soil management (PhD) | AHDB

Cover cropping was included as part of the following research programmes:

AHDB Rotations Partnership

AHDB-BBRO Soil Biology and Soil Health Partnership

Questions and Answers 

If you have a specific question related to this call please email research@ahdb.org.uk.  As part of the open tender process AHDB cannot discuss specific project details prior to submission of a proposal. All responses to questions will be anonymised and published.

Question: In your information about what you need for the "Updating guidance on cover crops (scoping review), You state that the content of this review should cover:

'1) Cover crop destruction - Timely and effective termination of cover crops...'

'2) Long-term soil health benefits of growing cover crops - Cover crops are grown for a variety of reasons... '
Then you state that ;

Out of scope of the review on long-term soil health benefits of cover crops:

• Establishment and destruction methods

We are slightly confused about this component of the advice, when the destruction method is detailed as a major component above. Are you saying that you are not interested in the choice of cover crop destruction method as it impacts long term soil health? This does not quite make sense in the context of the whole call. Clarification would be very useful thanks.

Answer: The scoping review requirements are split into two parts: 1) cover crop destruction, and 2) long-term soil health benefits of using cover crops. For 2) long-term soil health benefits of using cover crops establishment and destruction methods (i.e. the description of the methodology of the different establishment or destruction methods) should not be included. This part of the review (Part 2) can include how establishment or destruction of cover crops can impact on the long-term soil health benefits, where key soil health indicators have been measured. This is so the different reviews do not contain matching information, but some detail may still be relevant for both.