Comprehensive four-year trials across 17 arable farms in southern England have revealed that nature-friendly farming methods can significantly boost biodiversity, beneficial insects and crop yields.

But, perhaps as importantly, the study led by the UK Centre for Ecology and Hydrology (UKCEH) and Rothamsted Research highlighted that it also needs some form of support through agri-environmental payments for it to remain as profitable as business-as-usual conventional farming.

Researchers worked with the farmers to co-develop trials to manage three fields on each farm using different management practices, explains project lead Dr Ben Woodcock, an ecologist for UKCEH.  

See also: Groundswell 2025: Regen farming learnings from Gabe Brown

“What we wanted to do was look at whether nature-orientated or regenerative management practices had a net benefit initially on biodiversity, then on the provision of ecosystem services, such as pest control and pollination, and then on yield and profitability.”

Control

The control field was business-as-usual management by the farmer, which was managed without any consideration for field margins or any other unusual practice.

“It fitted into what they historically did, so if they used min-tillage across the farm, that was used. We wanted [the nature-friendly farming] practices to be super-imposed over what the farmer did,” Ben says.

Second field

The second field was managed to enhance ecosystem services (enhancing-ES). That involved growing overwinter cover crops ahead of any spring crop in the rotation and putting in 6m wildflower field margins on at least 50% of the field boundaries.

© Lucy Hulmes

“These provide refuge habitat and resources for beneficial invertebrates over winter and during the year and allows them to migrate into the field.

“The cover crops provide organic matter for the field, and help reduce runoff and soil erosion,” he says.

Third field

The third field was managed to maximise ecosystem services (maximising-ES). In addition to the cover crops and field margins, organic matter in the form of farmyard manure was applied at 30t/ha to the field in year one, and 6m in-field flowering strips were established at approximately 90m or three boom widths apart.

© Lucy Hulmes

“Most fields had two of these strips,” Ben says. “The idea is they reduce the size of the field and provide runways to allow the beneficial insects into the middle of the field.”

Other than those management practice changes, the fields were treated in the same way on each farm, including the use of inorganic fertiliser and pesticides, he adds.

Numerous assessments and measurements were taken over the four-year period of the trials with the study finding increased populations of earthworms, pollinators such as bees and hoverflies, and natural crop predators like ladybirds, lacewings and spiders in the enhanced and maximised ecological systems.

“These are things that we would expect,” Ben says. “But did it have any impact on yield?”

To find out the researchers used a combination of hand-harvesting crops from 0.5 sqm quadrats in 16 locations per field and validated and corrected the data using precision yield data from GPS-linked combines, which were available on about one quarter of the farms.

Yield

That analysis showed, albeit with a lot of scatter and variation between fields, farms and systems, a significant trend for an increased net yield per unit area as more ecosystem services were introduced, Ben says.

Modelling by the researchers suggested that the enhancing-ES system increased yields by an average of 0.3t/ha across the crops in the rotation, with the maximising-ES system increased yields by 0.32t/ha.

Results from just the precision yield data from combines indicated the maximising-ES system increased yields by double (0.6 t/ha) that of the enhancing-ES system, however, which the researchers hypothesised could account for within-crop variability potentially missed by hand harvesting quadrats.

“Most studies stop at this finding,” Ben says. “But we wanted to find out what does that mean in practice for the profitability of these systems.

“And what we found is that we start to get a different picture when you start considering establishment costs and income foregone from putting in field margins and/or in-field strips that remove land from production.”

Economics

Using National Association of Agricultural Contractors rates to determine the costs of the various nature-friendly farming practices used, and grain prices sourced from the AHDB, the researchers calculated relative profitability for each management system without any additional agri-environment scheme funding.

That showed the enhancing-ES approach would lose on average about £80/ha compared with business-as-usual, and £240/ha for the maximising-ES system, mostly because the cost of farmyard manure was fully costed in, Ben says.

Adding in environmental scheme payments, such as those available through the Sustainable Farming Incentive for growing overwinter cover crops, flowering strips in fields or as margins helped push the enhancing-ES system to parity with conventional management.

“But the maximising-ES approach remained less profitable than the business-as-usual treatment,” he says.

Within the 17 farms, there was a lot of variability, with farms that had more experience with nature-friendly farming practices tending to perform slightly better. “Experience and training matters with these things.”

There was also nuance that couldn’t be incorporated into the research, such as mixed farms might have much lower costs for accessing farmyard manure helping improve profitability, whether input use could potentially be reduced when using nature-friendly practices, and does long-term use of such techniques have an additive effect, increasing viability.

Conclusions

But the analysis showed that overall, as the area taken out of production for use in environmental schemes increased, the harder it was for a farm to be as profitable as business-as-usual.

“It suggests that subsidies are critical if we want to help farmers transition to what long term are likely to be more sustainable farming systems that increase soil health, benefit biodiversity, deliver ecosystem services and potentially make agriculture more resilient.

“It’s not that these systems can’t be profitable without subsidies, it’s just harder to achieve as you are managing complex natural processes to maximise yields,” he concludes.