Farmers were urged today to sow flowers such as knapweed, yarrow and bird’s-foot trefoil in field margins after research showed wild areas with flowering plants provided the best boost for wildlife.

Flower-rich edges in arable fields are better for wildlife than grass alone as they increase the number of insects, which are attracted to the nectar in the flowers.

Boosting the insect life in the field margins provides more food sources for farmland birds, which have seen major falls in numbers in recent decades and help to counteract the effects of pesticides.

Following the research, published in the journal Agriculture, Ecosystems and Environment, the RSPB urged farmers to consider incorporating flowers into margins they sowed this autumn.

While grasses supply seeds for birds to eat, insects provide an additional food source for many species, including “red listed” birds which are most under threat, such as linnets, yellowhammers and skylarks.

According to the study, field margins could provide food more cost-effectively than “whole farm practices” such as organic farming, but a variety of margins needs to be managed well to provide food all year round.

And hedgerows need to be provided alongside the margins to maximise nesting opportunities for birds and habitat for insects.

Richard Winspear, the charity’s senior agricultural advisor, said: “Grass margins are a popular option and they do have wildlife benefits, such as boosting predatory insects and small mammals and providing hunting areas for barn owls and kestrels.

“However, if farmers are planting margins, then there are significant benefits to adding flowers to the mix. Flower-rich margins hold the greatest variety and abundance of insects of any margin type.”