Scorecard tracks soil health at Monitor Farm

The soil health scorecard is underpinning an evidence-based approach to management at Wainfleet Monitor Farm. Joe Martlew looks at the results and how they can influence the farm’s direction of travel.

When Wainfleet Monitor Farm (Primrose Farm) joined the network in 2020, Gary and Debbie Willoughby (pictured) wanted to improve the farm’s soils.

Together, they oversee 75 hectares of owned land (as well as some tenanted and contracted land) on the Lincolnshire farm, just inland from Skegness.

Mainly sited on clay loams (with some siltier soils towards the southern end of the farm), the arable rotation includes wheat, barley, oilseed rape, linseed, beans and peas.

In 2020, the couple was near the start of the farm’s journey away from the plough towards less intensive cultivation approaches.

They embraced the soil health scorecard to baseline the condition of seven combinable crop sites across the farm.

In 2023, new scorecards helped unveil the impact of management.

The scorecard uses assessment results for soil health indicators and compares them to typical ranges for UK soil types, climate regions and farming systems.

The ranges act as benchmarks and can help reveal if the soil is healthy or if assessment results are outside of what is typical, which may need investigating.

• Visual evaluation of soil structure (VESS)
• Soil organic matter
• pH
• Extractable nutrients (phosphorus, potassium and magnesium)
• Earthworms

After being populated with assessment data, the online scorecard tool assigns a status to each soil health indicator:

• Investigate (red)
• Review (amber)
• Monitor (green)

The initial VESS results in 2020 showed plenty of room for improvement, with the assessors finding very firm soil structures that lacked porosity.

However, recent management actions are paying dividends. In the 2023 assessments, the VESS results shifted from mainly investigate (red) to mainly review (amber).

Adding organic matter, minimising cultivations, retaining crop residues and incorporating cover have helped to visibly improve the top 10 to 30 cm of soil over this relatively short period of time.

Roots and earthworms now move better through the soil, helping to break up the previously firm structure.

However, the direct drilling system has potentially introduced a new issue.

The use of the tine drill to incorporate organic materials and drill crops has resulted in a shallow compacted layer at 10 cm depth, which slowed water movement through the soil.

Example soil profiles used for VESS

The pictured soil received a VESS score of 3.5 in 2023 (where 5 is poor and 1 is good). It shows the relatively loose soil in the top few centimetres compared to the denser soil beneath it.

Gary and Debbie will continue to monitor this compacted layer. It may be necessary to reduce the number of passes or to mix the depth/type of shallow movement to improve the soil.

In the sites with the most challenging structural conditions, they may also need to consider timely low-disturbance subsoiling, followed by cultural options, such as the use of well-established cover crops.

At the Monitor Farm, soil organic matter (SOM) levels were strong from the outset.

Although levels dropped slightly in the 2023 assessments, this may not be a concern.

Organic materials had been freshly applied prior to the 2020 assessments, which would have boosted the SOM levels recorded.

Differences in laboratory methods may have also played a role. Using different laboratories for soil sample analyses can introduce variability. This can add ‘noise’ to the data, making it harder to interpret.

Importantly, SOM levels were still good in the 2023 assessments.

However, these experiences highlight the importance of making good notes during the assessments, which can be used later to interpret the results.

Although soil pH levels were not concerning at the farm, pH was slightly high or low at some sites.

The optimum availability of most plant nutrients occurs over a small range of soil pH values, so it is important to try to keep soils close to the optimum pH.

The AHDB website features guidance on the optimum (and target) pH for soils and how to tailor liming plans to meet specific site needs.

Phosphorus (P) and potassium (K) levels were generally good at this site (at both assessment timings).

Slightly high magnesium (Mg) levels were observed at several sites in 2023. Such levels may affect plant availability of other cations, such as potassium (K) and calcium (Ca). A good rotational magnesium management plan would help reduce and maintain soil reserves without compromising crop productivity.

The farm recorded a relatively large increase in earthworm numbers between 2020 and 2023.

The move towards less intensive cultivations would have contributed to this rise. However, the application of organic materials, incorporation of cover crops and maintaining good rotational diversity are also likely to have contributed to the success.

There are three ecological groups of earthworms (epigeic, endogeic and anecic). The diversity of ecotypes in the final assessments was also good. This is important, as each group delivers its own unique and important function in soils.

The soil health scorecard is revealing the condition of the land and directing an evidence-based approach to management at Wainfleet Monitor Farm.

The soils are in a transition period, as Gary and Debbie move from a high-intensity to a low-intensity cultivation system.

They will continue to monitor their soils and adapt management to help them farm more sustainably.

To access the scorecard and instructions, visit ahdb.org.uk/scorecard