The increasing digital reach of the Nutrient Management Guide – RB209

Heather McCalman summarises the tools that can help you fine-tune crop nutrient management.

In 2015, we took on responsibility for RB209 from Defra. Since then, we’ve invested in numerous research projects and several revisions, which include the 2026 edition published in the spring.

It was the first update since the 2024 strategic review, which saw nearly 1,000 people tell us what RB209 does well, how it could be made better and the main nutrient management challenges.

The review identified a strong demand for better data to target crop nutrient requirements across a wide range of farming situations.

As digital options play an increasingly important role in this tailoring process, we’ve released several online tools in recent years.

In 2018, we published the first interactive maps to show excess winter rainfall, which categorises rainfall as either low, moderate or high across the UK.

We update the maps every year during winter and spring.

When used alongside RB209, the categories indicate the potential impact of nitrate losses on soil nitrogen supply.

Elevated fertiliser prices, especially since 2021, led to a new economic optimum, in terms of the point at which the value of extra grain/oilseed produced is no longer worth the cost of the extra nitrogen applied.

This calculator accounts for current fertiliser and grain/oilseed prices to guide adjustments to standard farm nitrogen rates.

We also developed a cost-benefit calculator for nitrogen fertiliser use on grassland.

Released in 2022, this Excel-based tool uses soil analysis results for core soil health indicators and compares them to typical benchmark ranges for UK soil types and climate regions.

In addition to extractable phosphorus, potassium and magnesium, the scorecard also considers pH, soil structure, earthworms and soil organic matter.

In 2025, we released our most recent tool, which uses RB209 and fertiliser price data to quantify the nutrient and monetary value of various organic materials in specific situations.

As part of RB209, we maintain a web-based application programming interface (API), which packages RB209 data for software solutions and is used by several commercial companies.

Defra also used it to underpin its free online nutrient management planning tool, which was released in February.

The tool already uses MANNER-NPK calculations to estimate crop available nitrogen, phosphate and potash supply from organic manure applications.

This month, a version of MANNER–NPK was added as a standalone tool to provide a quick estimate of nutrients from organic manures and their financial value without the need to complete a full nutrient management plan.

Developed with ADAS and RSK Business Solutions, the tool currently covers England and Wales.

There are plans to extend the tool to cover Scotland.

We also continue to invest in the interactive GB fertiliser price series dashboard to show price trends for key fertiliser products.

In response to the conflict in the Middle East, we increased the frequency of the price reporting from monthly to weekly.

We also continue to develop our Slurry Wizard, which was first released on CD rom in the early 2000s.

In addition to managing storage, the Excel-based tool calculates the total amount of nitrogen in stored slurry.

In the 2024 review, you asked us to improve evidence on the nutrients that enter and leave the system across the rotation.

Organic materials are a key part of the equation and Section 2 saw the most revisions in 2026.

It features better data on crop-available nutrients from various organic materials, including new tables on digestate nitrogen from food-based or farm-based sources.

We are also reviewing the typical nutrient values for organic materials for a wide range of sources commonly used on farms.

The review considers:

• Analyses of representative farm samples
• Accessible commercial and public-domain datasets
• Recent and active research
• Potential contaminants

We continue to invest in research on nutrient uptake and release from cover crops.

Around 150 farmers and advisors took part in an ADAS-led review of the topic last year, with most (86%) expressing a ‘great interest’ in having a practical cover crop nutrient management tool.

This year, we continued to work with Anglian Water, Southern Water, and Wessex Water to fund a simple decision support tree that accounts for key variables, such as soil type, dominant cover crop species and above-ground biomass at destruction.

Developed with potential users, we aim to release it this winter.

Investment in soil health, including soil nutrient availability, continues to be a top priority in our letterbox that captures research ideas from levy payers. It is why we will continue to develop RB209.

Most tools cited in this article can be accessed from our tools for cereals and oilseeds page.

Exceptions are: