How AH Worth is improving soil health for more sustainable farming
Award-winning Lincolnshire vegetable grower, AH Worth, has been striving to improve soil health, cut chemical use and protect biodiversity with support from Fera. Farm manager, Simon Day, and Senior Plant Nematologist at Fera's, Bex Lawson, explain how they have been working in partnership to assess regenerative agriculture practices using nematodes as biological soil health indicators.
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Key Farm Data
3400Ha of grade 1 fertile silt soils Producing over 350 ha of potatoes.
Land is also let for specialty salads, leeks, Kale. Some other crops grown: winter wheat, sugar beet, vining peas & maize
M&S supplier and one of the supermarkets indicator and innovation farms.
Leaf demonstration farm, regularly hosting visits for farmers, schools and interest groups.
What was AH Worth looking to achieve?
AH Worth has been moving towards more sustainable potato production by focusing on reducing greenhouse gases to help cut the carbon footprint of the farm business. To achieve this, they have been using regenerative principles such as reduced soil cultivation, cover crops and investments in soil biodiversity.
As part of Marks & Spencer's 'Farming with Nature’ campaign, the supermarket funded Fera to carry out research trials on cover crops and their impact on soil health. With establishment costs of £80/ha for some cover crops at AH Worth (as of 2021), the soil health data from these trials can prove this outlay is a worthwhile investment.
Simon has experimented with biofumigant cover crops and recently more traditional mixes, including vetch, phacelia and radish.
What we want is good ground cover to protect soil quality, but minimal management, he says.
To measure the impact of these changes and provide direction on soil management practices at AH Worth, Fera researchers were brought in.
Nematode populations are excellent bioindicator of soil health,” says Bex. Analysing and classifying nematode population dynamics within soil samples gives us an indication of soil biodiversity and a measure to access changes over time, this enables growers to monitor the impact of management changes.
It is important to understand the effects that different cover crop mixes have on soil and ensure growers are utilising these crops to best effect for their particular needs.
Solution & approach
Fera conducted Nematode Bio-Indicator analysis, which identifies, and analyses shifts in the nematode community to determine whether the chosen agricultural practice initiative is beneficial for good soil functioning over time.
Why Nematodes?
Nematodes are ecological indicators:
- Small, diverse, abundant and ubiquitous:
- They interact directly with soil (physical, water and chemistry)
- Resident within the soil food web
- Cover all the soil trophic groups within the food web.
2. Indicator of soil disturbance and impact on communities
- Constant soil disturbance does not allow enough time for nematodes groups with a longer life span and low fecundity to recover, this can eventually eradicate them, having an immediate effect on soil biodiversity.
3. IPM control
- Certain nematodes feed on insect larvae, other nematodes, slugs and snails, playing an important role on soil biological control and crop rotation strategies.
4. Stimulator of nutrient cycling
- By feeding on bacteria and fungi, it stimulates these populations to renew consistently, maintaining the release of nutrients.
5. Indicator of soil contamination
- Nematodes are very sensitive to pollutants, chemicals, and N fertilisers, being often used to evaluate soil toxicity and its effect on communities.
Project scope & methodology
Fera assessed cover crop establishment on grade one fertile silt land using nematodes as ecological indicators to measure the change in soil health.
Field margins were used as a baseline and control sample for field changes.
The project involved:
- Soil sampling pre, during and post cover crop establishment.
- Extraction of nematodes from soil using whitehead tray method.
- Taxonomic identification and counts of nematode genera / species, trophic groups assessment using dissection / compound image analysis microscopy.
- Assessment of nematode population dynamics using ecological indices.
Results and impact
Cover crops contributed to maintaining soil structure and supporting the soil ecosystem, even under challenging conditions.
Throughout the trial, the cover crop faced some challenges in establishing and developing a particularly dense canopy. However, nematode analysis revealed a positive shift from a disturbed to a maturing ecosystem as shown in the margins, highlighting the potential benefits of cover cropping in minimising soil disturbance and supporting ecosystem development.
By the final analysis, both the field and margins showed a return to a disturbed state. Changes in the nematode population further emphasised the dynamic nature of soil ecosystems and their sensitivity to environmental conditions. The presence of aquatic nematodes suggested a shift towards a wetter habitat, consistent with environmental data showing the wettest month on record, causing water erosion impact on grade 1 slit land.
Despite these extreme conditions, the fields with cover crops remained free of standing water and remained workable, underscoring their critical role in preserving soil structure during extreme weather patterns.
How has this sustainability project benefitted AH Worth and the wider Agricultural sector?
AH Worth have been using cover crops since 2021 at a cost of £80/ha. Fera’s soil health data results confirmed that establishing this management practice has been a worthwhile investment for the business. The analysis provided valuable insight into the positive impact the cover crop had on soil structure, its ecosystem, and its impact on reducing greenhouse gases to help cut the carbon footprint of the farm business.
Nematodes Bio-Indicator analysis can help farmers, such as Simon, with valuable insights into their soil ecosystem and its connection to agricultural practices providing a sound evidence-based approach to aid informed decision-making, for sustainable land use. Furthermore, identification and understanding of beneficial nematode populations ensures IPM strategies can be tailored for best effect. Pest host preferences can be considered during crop planning to help reduce crop damage.
The findings contribute to the wider agricultural sector by highlighting the power of ecological ecosystem assessments to enable growers to use ecosystem changes to monitor management decisions. This knowledge will help support growers in risk-based decision making to enable provision of more resilient soil management strategies, such as IPM strategies and reduction of the use of chemicals.
