HOW MANY cereal farmers does it take to increase wheat yields across the UK? Only 20, but 15 of them are still needed from the western Midlands, Yorkshire and southern Scotland.

Scientists from Rothamsted Research are looking for 20 farms spread across the UK to provide research access for four years to two wheat fields, working on a rotation. They have found five farms in south eastern England, but still need 15 more in Hereford, Worcester and the Welsh border; south eastern Scotland and northern Northumberland; and Yorkshire.

“We’re after two average-sized fields per farm, from 4 to 15 hectares,” said Ian Shield, an agronomist at Rothamsted. “Ideally, we’d like one that the farmer describes as ‘always good’ and another described perhaps as ‘I never know what to expect’.”

Three or four researchers would visit the fields about four times a year when crops have been sown. They would take soil measurements, recording texture and penetration, for instance, and analyse samples for their chemistry. Weed and disease pressures would be assessed. They would also observe crop architecture.

Real data collected from the ground and imaging recorded from space promise a wealth of detail that will enable the researchers to compare their findings against predictions by mathematical models to rate the factors that influence production yields.

“Farmers can have all the information relating to their own farms and, of course, access to our results,” said Mr Shield. “We would also need management records from farmers and any historical yield maps for the fields involved. And we can anonymise locations and data, if required.”

At Rothamsted, Mr Shield is investigating the 'Biophysical Limitations on Crop Productivity' as part of one of the institute’s five strategic programmes to 2022, Achieving Sustainable Agricultural Systems. The programme is jointly led with the Centre for Ecology and Hydrology.

The regions chosen for the productivity study reflect the variety of conditions, from topography to climate, that UK farmers manage on a day-to-day basis. The aim is to discover what factors influence yields and how they change under different conditions.

The study comes in the wake of Defra Secretary Michael Gove signalling a post-Brexit policy focus on encouraging greater productivity and environmental stewardship in farming.