Research review: Development of the Nutrient Management Guide (RB209) Section 3 Grass and forage 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, and 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 an invitation to tender for a project to collate and evaluate recent UK-relevant research and data on grassland and forage crop nutrient management, including diverse leys (grass and clover swards, herbal leys). The aim is to review existing data that can be used to support the development of guidance in Section 3 (Grass and forage crops) of the Nutrient Management Guide (RB209) and identify where further research is required to inform future updates to this section of the guide. No fieldwork is expected to be completed as part of this project. Analyses of existing datasets may be included.

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 section 10.

A full copy of the call can be found here:  Research review Development of RB209 Section 3 - call document October 2025 FINAL.pdf

2. Background

AHDB produces the Nutrient Management Guide (RB209), which is recognised as the industry standard for nutrient management information and guidance in England, Wales and Northern Ireland. Updates to the guide are made based on evidence provided by research.

In 2024 a strategic review of RB209 was undertaken to ensure that the guide remains relevant for current farming systems. Various areas for future development were highlighted in the findings, ranging from nutrient management planning, nutrient use efficiency, information to tailor recommendations for different farming systems, and improving the format of the publication.

The review findings also specifically highlighted a requirement to update RB209 Section 3 (Grass and forage crops), including the following feedback:

• Improving the grassland section to make it more straightforward to follow for all users

• Soil pH recommendations for grassland: optimum pH for grass, including systems with clover

• Soil analysis and interpretation in grassland systems to help guide decision making

o   Consideration of sampling depth (appropriate depth for different systems)

o   Interpretation of nutrient availability as provided through detailed soil analysis, particularly P inputs

• Nitrogen recommendations for grass: extend the information provided, for a range of different systems; better reflect typical farm practice

• Guidance on sward quality: recommendations for different types of sward, e.g. ryegrass dominant compared to diverse plant species  

• Guidance required for diverse leys: herbal leys, white clover/grass, red clover/grass

o   N rate and timings for diverse leys, to account for swards with varying levels of clover

o   N, P, K and pH recommendations for multispecies swards comprising grass, legumes and herbs

o   Importance of soil P and K fertility where clover species are included; P and K offtakes and application timings

• Guidance required for forage crops (fodder beet, lucerne, maize, rye, turnips)

o   Recommendations for forage crops to be grazed in situ (e.g. fodder beet) rather than assumed to be harvested 

o   Update nutrient requirements for forage maize

3. Related information

The last major technical review of RB209 Section 3 (Grass and forage crops) took place in 2016. RB209 Research Review - WP3 - Grass and forage crops.pdf

In recent years, research has been funded to update technical information in RB209 Section 4 (Arable crops), with additional updates being made to RB209 Sections 1 and 2.  However, fewer updates have been made to Section 3 since AHDB first published the Nutrient Management Guide (RB209) in 2017. A short project in 2022 looked at nitrogen recommendations for grassland, considering increased fertiliser prices.

4. Purpose of the tender

This is a call for a desk-study to synthesise and review evidence to inform updates to RB209 Section 3 (Grass and forage crops), as well as recommend future research to support development of this section of the guide. The output will be a final report, identifying where robust, quality data exist to inform updates to nutrient recommendations. Where appropriate, new data should be presented in a format consistent with the existing tables of RB209 Section 3, alongside contextual information, for consideration for publication. References and full data sources will be required. Any proposed updates to the current RB209 guidance as a result of this project will be reviewed by members of the Crop Nutrient Management Partnership.

Where robust data are lacking (i.e. insufficient evidence for nutrient recommendations for specific systems or crops), the review should provide a narrative summary of findings that can be used by AHDB for knowledge transfer activities on grassland and forage crop nutrient management.

A secondary aim for this project is to consider how existing (and new) information is presented in RB209 Section 3, to ensure guidance is clear, and the publication is straightforward to use (e.g. content order, format, layout, provision of worked examples etc).

The final report will detail the findings of the objectives set out below.

5. Tender Objectives

The objectives of the desk-study are as follows:

1. Critically review UK-relevant research to identify robust data to inform updates to current nutrient recommendations and technical content of RB209 Section 3
2. Identify and critically evaluate relevant existing datasets that could be used to provide guidance for grassland/forage systems where gaps have been identified in RB209 Section 3, e.g. guidance for nutrient management in diverse leys and forage crops. Temperate climates representative of the UK agro-climatic regions should be considered, where research has included replicated trials over multiple seasons.
3. Identify situations where there is a lack of robust research or trial data to provide nutrient recommendations for specific grassland/forage systems, and provide a summary of best available guidance for these situations
4. Provide recommendations for further research required to address evidence gaps
5. Evaluate options to improve the flow of information and ease of understanding for users of the RB209 Section 3 publication (e.g. content order, layout, user experience). Note that the guide will remain in landscape orientation for publication
6. Produce a final report
7. Optional: Provide examples or case studies to support farmers in understanding nutrient recommendations for their own grassland farming system

An interim project presentation will be required, to provide an update to the Grass & Forage Technical Working Group of the Crop Nutrient Management Partnership.

A final project report will be required along with participation in our annual project monitoring exercise. Further information and example templates for these reports can be found at AHDB Cereals & Oilseeds research report templates.  Please note that the final report template for this project will be adapted to reflect the cross-sector nature of the work.

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.  The scope covers all grassland systems and forage crops, with data relevant to UK agro-climatic conditions. Some analysis of existing data may be involved to support the development of content for RB209 Section 3 and/or supplementary material. The UK Crop Nutrient Management Partnership handbook Appendix 4 outlines ‘Guidelines for crop nutrient management field trials’, which should be considered in evaluating research or trials data to feed into proposed updates to guidance in RB209.

Other UK-relevant nutrient management guidance, such as the Scotland Technical notes, should also be considered.

7. Project Duration, Budget, and Collaboration

AHDB has set aside a maximum total budget of £40,000, inclusive of VAT, over four months.

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 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

Applicants should complete AHDB Research and KE Application Form - Full Proposal Small, referring to the guidance notes to aid completion. Applicants should also refer to Section 9 below for criteria used in evaluation of proposals, noting that this replaces the “Full project proposal assessment form” on page 12 of the full proposal document.

Completed application forms should be submitted to research@ahdb.org.uk no later than noon on 24^th November 2025.

The earliest date of commencement for work funded as a result of this call will be 5^th January 2026.

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 contracts” 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).

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.

An evaluation panel will assess submissions in line with the scoring criteria and weightings in section 9 to decide the best outcome for this research project. The selection will be an open and fair competition according to AHDB’s procurement policy, which complies with the UK’s international subsidy control commitments.

9. Evaluation and award of contract

All submitted proposals will be reviewed by cross-sector research representatives within AHDB, and members of the Research and Knowledge Exchange Committee. 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 the UK’s international subsidy control commitments.

Evaluation of proposals will be on the following basis:

10. Proposal submissions

Submissions to be made electronically:

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

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

Research and KE funding | AHDB terms and conditions shall apply to any contract awarded as a result of this request for quote.

If you have specific questions relating to this call, please email research@ahdb.org.uk. All Questions & Answers will be published.

As part of the open tender process, AHDB cannot discuss specific programme details prior to proposal submission.

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