Lessons still need to be learned about the efficiency and viability of using cover crops to improve soil health, retain nutrients and reduce pressure from weeds.

That was one of the messages for growers at an event which discussed the results of trials to assess the merits of reducing ploughing and growing cover crop mixes between commercial crops.

The farm walk was hosted by agricultural management firm Sentry at Hill House Farm in Hedenham, near Bungay, and included presentations from plant-breeding company DSV.

John Barrett, business manager for Sentry Norfolk, said part of one field had previously been planted with a fast-growing mix of buckwheat, sunflower, oat, phacelia, false flax, linseed, deep-till radish, Abyssinian mustard and bristle oat.

The aim was for the range of roots to improve the soil structure, allowing the following crop of spring beans to be drilled without the need for additional cultivation passes.

'But there was just too much biomass,' said Mr Barrett. 'The sheer volume meant we couldn't direct drill it, meaning we had to cultivate it and then drill it. It defeated the object of growing a cover crop.

'We are trying to reduce the need to plough and cultivate on what is a particularly nasty and heavy field. We know if we plough, it will come over very wet and shiny and it will be difficult to get a good seed bed.

'This year, the whole field has been covered with a black oats and vetch mix, which is about a third of the height and less 'woody'.

'We want to utilise our existing machinery to drill into that mix in the spring. It is coming into spring wheat and that will give us some flexibility in the timing.

'All of us are still very much learning about how we can make it (cover cropping) fit our own situations without having to go out and spend a lot of money on new machinery.'

Emma Bedford, of DSV, said cover crops needed to be seen as a long-term investment in soil health.

'You will not see the real benefit of it for at least five years,' she said. 'Before you put it in you need to think about what your objective is. Is it to improve soil humus? Is it have cover on your land over the winter? Is it to improve soil structure?

'The reduction in your black-grass is to do with spring cropping rather than the cover crop. The cover crop helps, but it is the spring cropping which is reducing black-grass.'

Is your farm working to improve soil health? Contact chris.hill@archant.co.uk.