Decision tree for nutrient management following cover crops

1. Introduction

The Agriculture and Horticulture Development Board (AHDB) is a non-departmental Government body, funded by levy income from farmers, growers and others in the supply chain, and managed as an independent organisation (independent of both commercial industry and of Government). The role of the AHDB is to help improve the efficiency and competitiveness of various agriculture sectors within the UK. Our purpose is to help our farmers, growers and industry to succeed in a rapidly changing world.

As AHDB is funded in this manner, value for money is paramount, we welcome suppliers who can offer innovative and cost-efficient solutions to meet our needs, whilst also offering superlative service that will enable us to create a world-class food and farming industry. Solutions should look to help us not only reduce costs but increase business flexibility, lift productivity, bring people together to collaborate, innovate and drive change throughout. Further information about AHDB can be found here: https://ahdb.org.uk/

This document is a request for quotations for a co-funded initiative between AHDB, Anglian Water, Southern Water and Wessex Water, to develop a practical and robust decision support tree to guide farmers and advisors on the measurements/assessments they could take to understand the likely level of fertiliser reduction/requirements following their cover crop.

Submissions should be based on the information contained within this document and in the format outlined in section 8. Deadlines and submission instructions are contained in sections 10 to 12.

2. Background

The widespread interest in cover crops across the UK agriculture industry is clear, with potential benefits both to crop production and to the wider environment reported across a disparate pool of knowledge arising from industry trials and scientific literature. It is also well recognised that harnessing the benefits of cover crops is case specific with species mixes, timing, soil type and condition, as well as local environment, included as factors influencing the outcomes.

AHDB and our industry partners on this initiative; Anglian Water, Southern Water and Wessex Water have all supported trials and research on UK cover crops and have a keen interest in ensuring farmers are equipped to make sound decisions on the integration of cover crops into their farming systems. The current funding opportunity builds upon a recent desk study that scoped the feasibility of creating a decision support tool to help UK farmers predict nutrient release from cover crops to the following crop. As part of the recent desk study nutrient release measurements were identified within scientific and grey literature dating back to 2010. However, the published literature contained a limited amount of data. Making wider use of industry data sets would be beneficial to strengthen the contextual data.

The study also surveyed farmers and advisors on the relevance, use and nature of a nutrient release decision support tool. Eighty six percent of respondents (n=150) showed great interest in using a decision support tool to guide nutrient management planning following cover cropping.

The project went on to recommend development options for decision support tools. It is these recommendations that this current funding opportunity seeks to pursue. In particular, the development of a farmer/adviser-facing decision support tree that is based on data that already exists for the UK (beyond that found in the recent desk-study), with supplementation from temperate-climate data where UK data is lacking.

3. Related information

4. Purpose of the tender

This is a call for a desk-study to identify and review existing evidence to develop a simple, practical and robust decision support tree to guide farmers and advisors on the likely level of nutrient adjustments following cover crops. This will be developed using the measurements collated by the recent desk-study project and strengthened by wider industry data (to be sourced), including data from UK water companies.

5. Tender objectives

The objectives of the desk-study are as follows:

• Collate a sufficient amount of good quality nutrient release data to generate robust decision tree guidance on likley nutrient adjustments following cover crops
  • Identify and connect with industry stakeholders that hold data on the amount and timing of nutrients released from cover crops with the aim to use their data in an anonymised form
  • Assess and critically analyse the collated measurements
  • Provide a collated dataset for future development purposes, including a more detailed decision support tool
• Produce a decision tree for use on a webpage and within publications to guide farmers and advisors on the likely level of nutrient adjustments following cover crops
  • Include nutrient release factors such as (but not limited to): soil type, weather conditions, timing of planting, cover crop establishment/growth, destruction method and timing, previous and following crop and cover crop species. All inclusions should be justified.
  • Identify crop and soil etc measurements and assessments that will help guide farmers and advisors through the decision-making process
  • Indicate the level of confidence in the data to guide the decision-making process
  • Ensure that current and emerging UK cover crop practices are included as well as any likely to develop in the future
  • Ensure the decision tree meets the need of farmers and advisors through adequate end-user-testing
  • Link to cover crop resources that could support users of the decision tree with general cover crop guidance beyond nutrient management
• Provide recommendations on how the decision tree can be improved where underlying data is currently lacking and where additional measurement or management factors could usefully be added when data becomes available.
• Produce a final report

6. Scope and Approach

There is no expectation of field work for this call and work will be carried out primarily as a desk-study.

Collated data should reflect UK farming conditions as well as current and emerging cover crop practices. In the first instance, data from the UK is to be used. However, where UK evidence is weak, evidence from temperate regions of northern Europe can be brought in.

Nutrient release data should include the amount and timing of nutrients released from single and multi-species cover crops grown at any time of year. Data sources do not have to include all of the listed measurements to be considered within this project.

Final project reports will be required along with participation in our annual project monitoring exercise. Further information and templates for these reports can be found at AHDB Cereals & Oilseeds research report templates. 

7. Project Duration, Budget and Collaboration

The budget for delivery of this desk study is £40,000, inclusive of VAT.

Additional budget of up to £15,000, inclusive of VAT, is also available for further work that will add value to the project outcomes (see Section 9).

Joint proposals from two or more contractors are acceptable and encouraged where there is added value. AHDB may, if it is deemed desirable, request applicants to form a consortium to work together. There should be one organisation designated as the lead organisation for the Research Partnership which is responsible for sub-contracting partners, project management and delivery. The group size should be manageable. Prospective partnerships can comprise both research institutes and industrial partners, be multi-disciplinary, and draw on a range of research experience for a number of crops. Therefore, the group does not necessarily need to have a history of working together previously. Further, priority will be given to the applicants with in-kind and or cash funding from the industry.

8. 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.

9. Evaluation and award of contract

All submitted proposals will be reviewed by relevant representatives within AHDB and the co-funding organisations. If required, external peer reviewers may be sought. The selection will be an open and fair competition according to AHDB’s procurement policy, which complies with EU state aid rules.

AHDB reserves the right to not proceed with any application.  

Evaluation of proposals will be on evidence provided against the following criteria: 

10. Tender submissions

Quotes must be received by noon on 10 February 2026. Submissions must be made electronically to research@ahdb.org.uk quoting the reference 'Decision tree for nutrient management following cover crops.'

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

On submitting a proposal, please ensure you have read and accepted our terms and conditions, these are available on our website here under the “Standard agreements” heading. Any organisation receiving funding from AHDB shall comply with the terms and conditions specified in the Research Funding Agreement. AHDB will not be held responsible for any expenses or losses incurred by applicants in the preparation of an application(s). 

11. Timetable

Please note these timescales are approximate and may change.

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

12. 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:

If you would like to download this Invitation to Tender as a pdf document, click here

Questions and Answers

Question: We note that the work should build “upon a recent desk study that scoped the feasibility of creating a decision support tool to help UK farmers predict nutrient release from cover crops to the following crop”; however, we have been unable to find a copy of the report that came out of that work. In order to properly produce a tender that builds on the previous work it would be very useful to see a copy of the report produced for that work; so, we were wondering whether this could be made available to those tendering for the new project?

Answer: The reports for the Nutrient release from cover crops desk study can be found here: Nutrient release from cover crops (desk study) | AHDB