On-farm trials at Strategic Cereal Farm Scotland (2020–2024)

Host farmer: David Aglen

Location: Balbirnie Home Farms, Fife

Duration: 2020–2024

AHDB Strategic Cereal Farms put cutting-edge research and innovation into practice on commercial farms around the UK. Each farm hosts field-scale and farm-scale demonstrations, with experiences shared via on-farm and online events to the wider farming community.

Strategic Cereal Farms

Reducing artificial inputs is a long-term goal for Strategic Cereal Farm Scotland.

This page features a summary of information published in the latest annual report.

Cover crops ahead of direct drilled spring barley

This work established a cover crop (oats, peas and beans) ahead of a spring cash crop and quantified the benefits, including the potential to reduce inputs.

Three cover crop treatments were established in each field (Midbank and Trough Park):

• No cover crop
• Cover crop destroyed with glyphosate (sprayed)
• Cover crop destroyed with sheep (grazed)

The trial also explored three drill dates:

• Standard local practice (mid-April)
• Standard local practice minus 7–10 days (early April)
• Standard local practice plus 7–10 days (late-April)

The impact of cover crop treatments on establishment, growth and yield of direct drilled spring barley was assessed. The impact on soil (chemistry and structure), natural enemies, pests, weeds and diseases were also assessed.

Headlines (harvest 2024)

• Good cover crop establishment at Midbank
• Poor cover crop establishment at Trough Park 
• Crop establishment and yield were generally better in 2024
• No yield penalty was associated with the cover crop management options trialled 
• Weed burdens were similar in the cover crop treatments, indicating that neither cover crops, nor their destruction method impacted weed burdens
• The main spring barley diseases recorded were rhynchosporium and ramularia
• There was no significant link between cover crop management treatment and crop disease
• There was a strong link between drilling date and disease: as later drilled plots (in both fields) senesced later, ramularia was higher in these plots, which was an artifact of having more green leaf
• In Trough Park, spring barley yields were 0.5t/ha more in grazed cover crops, compared to sprayed-off cover crop or no cover crop treatments
• In Midbank, yields were higher than Trough Park and there were no significant differences in yield across treatments
• The result potentially reflects that the benefits of cover crops were greatest in Trough Park, possibly due to a slightly poorer soil structure
• Soil chemistry and structure differed between fields but differences between cover crop treatment within the same field were not seen
• The impact of cover crop treatment on natural enemies varied between fields making it difficult to draw definitive conclusions. This could be due to differences in establishment or other inherent differences in the two fields (e.g. soil properties)  
• Mobile natural enemies could have redistributed following cover crop destruction making it difficult to see treatment effects in these small plot trials  
• Aphids were rarely observed early in the season and there was no evidence that the cover crop acted as a green bridge 
• Slugs and slug damage were also low across field and cover crop treatments
• Burning off the cover crop with glyphosate after drilling the spring barley crop resulted in poorer crop establishment and reduced yield in the first three years of trials but grazing cover had a positive impact on harvest 2024 yields in one field

Action points

• Assess Soil pH regularly and use lime to maintain an optimum soil pH (low pH can affect efficiency of key nutrients, including phosphorus) 
• Increased traffic and stock use can cause soil structural problems but cover crops can help alleviate these
• Visual soil health scorecards can highlight problems early 
• Read practical guidance for Scottish farmers to help value soil

Optimising crop nutrition

This work aimed to determine whether in-crop monitoring, including growth and development and tissue testing, can be used to amend crop nutrition, while considering the economic benefit on crop health, yield and grain quality. This winter wheat trial used in-crop measurements to tailor nitrogen applications from the farm standard AN rate (160 kg/ha).

Another multi-season winter wheat trial examined the use of various nitrogen products/strategies:

• Farm standard ammonium nitrate (AN) rate (160 kg/ha)
• AN (80 kg/ha) followed by liquid urea fertiliser (UAN) to give a total N of 160 kg/ha
• UAN (80 kg/ha) followed by followed by four to five applications of 10–15 kg/ha of foliar urea (and three application of trace elements) to give a total N of 140 kg/ha

Headlines (harvest 2024)

• Harvest 2024 trials were associated with slow spring crop development but better field uniformity compared to previous seasons
• Early leaf canopy differences were attributed to minor field variations in nitrogen supply
• Despite some striping along tramlines, the crops showed no nutrient deficiencies, though monitoring for nutrients like manganese (Mn) was recommended
• The results indicated how some crop measures, like the Green Area Index (GAI) and SPAD (leaf chlorophyll/nitrogen status), can help monitor crop health and inform management
• The use of BRIX and leaf SAP measurements for crop health (e.g. to measures plant sugar status) remains uncertain
• Liquid plus foliar nitrogen management may be more efficient than the standard ammonium nitrate plus foliar treatment

Action points

• Tailored nitrogen treatments (to reduce total nitrogen applied by 20–30 kg/ha) show promise to improve nitrogen efficiency without sacrificing crop health
• The value of BRIX and leaf SAP measurements for crop health is still uncertain (further testing is needed to establish their relationship with crop performance)
• Continue to use GAI and SPAD for early crop assessments to guide nitrogen management
• The combined use of GAI, SPAD, and crop nitrogen pool (GAI x SPAD) are reliable indicators of crop potential and nitrogen needs
• Monitor key nutrients, such as manganese (Mn), especially when they are in the intermediate range for optimal crop growth
• Consider further adjusting tailored agronomy treatments to fine-tune nitrogen levels for improved efficiency in future seasons
• Incorporate remote sensing (e.g. drone flights and yield maps) and representative sampling zones to monitor crop health, soil moisture, and identify management needs for different field zones

Impact of regenerative management on pests and natural enemies

Researchers used simple survey techniques to collect baseline biodiversity data, based on natural enemies and key pests, in May 2021.

Six fields and their margins were assessed: three conventional and three regenerative.

The regenerative fields featured cover crops, livestock, reduced inorganic fertilisers and improved hedgerow management.  

Follow-up surveys were conducted in these fields in May 2024.

Headlines (harvest 2024)

• Ground beetles, rove beetles and parasitic wasps generally increased. However, it was difficult to determine if this was due to natural fluctuations or regenerative agricultural practices
• Regenerative agriculture practices could potentially reduce natural enemies in field margins. For example, livestock grazing could reduce overwintering habitats (e.g. dense tussocky grass). However, more research is required to draw firm conclusions
• Solitary bees are rare at this farm. Increasing early season resources, such as willow, hawthorn and fruit trees, near potential nesting sites (e.g. solitary bee hotels, stone walls or earth banks) could help promote these important but often overlooked pollinators 
• Slugs and aphids were rarely found in the fields, although slugs were common in field margins
• There was no clear evidence that adoption of more regenerative practices impacted on pest risk
• Natural enemies generally increased between the 2021 and 2024 assessments. As invertebrate populations fluctuate annually, it is difficult to determine if this was due to environmental improvements or annual fluctuations  
• As with any change, it is important to continuously monitor fields to detect emerging issues early

Action points

• Do not disturb tussocky field margins, as many natural enemies overwinter in them (this includes protecting field margins from grazing)
• Both aphids and slugs were rarely present in the fields early in the season
• The in-field trends did not indicate an increased pest risk associated with regenerative practices
• Some practices may increase risk (e.g. reduced tillage, cover crops), so it is important to conduct regular monitoring to detect issues early