Arable farmers advised to hold their nerve to beat black-grass

The yield-killing weed has become a constant headache on many farms, as the majority of black-grass plants now emerge within the growing cereal and oilseed rape crops, making it more difficult to destroy them.

Delaying the autumn drilling date allows more weed to germinate and be sprayed off before sowing, and is also thought to make residual pre-emergence herbicides up to 30pc more effective, and any remaining black-grass less competitive.

But it is a gamble – as conditions deteriorate in the autumn, many farmers would prefer to take advantage of good weather and drill earlier rather than risk leaving it too late to establish a viable winter crop.

Andrew Melton, regional sales manager at Frontier Agriculture, said farmers shouldn't be tempted by a false sense of security – recommending his clients wait until this week to drill their worst-affected fields, with a good spring crop a better fallback option than a weed-ridden winter crop.

'There has been a lot of talk about the issue of blackgrass and how we are going to manage it,' he said. 'This year has brought us to a bit of a watershed moment where people who have got an increasing problem just couldn't carry on with what they were doing.

'Most people have realised the key to all this is rotation, rotation, rotation... with more rotation on top of that. That is not just in terms of cropping, it is ploughing, primary establishment regime and nutrition.

'We had a good dry summer, which allowed us the opportunity to rectify some drainage issues. That gives you the ability to get on earlier in the spring and stay on land later in the autumn and make the most of the opportunity to drill things in the right conditions, rather than forcing it.

'The first zone of the soil is not super-saturated and anaerobic, which means wheat and barley would grow particularly well. But the thing that puts the dampeners on it is that black-grass enjoys it too.

'It had delayed dormancy and started to come up three or four weeks ago, and get a bit of a run.

'Later drilling has advantages and disadvantage. The advantage should be that you are getting more moisture and better establishment and you get the performance from your residual chemicals. The disadvantage is that the weather goes against you and you cannot get the crop in.

'If you have identified you have a nasty blackgrass problem and you are at the last chance saloon, my plan is to drill from October 17 onwards. Maybe you do the less problematic fields earlier, but if you have got really bad fields you leave them late. This is when the big impact will be on black-grass.

'It is a difficult decision. But if they cannot establish it in the right soil conditions in the next couple of weeks, then after that we can look at other options like spring wheat and spring barley. It is no good crowing about having drilled in September if it's swamped with black-grass.

'I had one chap who said he could not afford to grow spring beans. I said you cannot afford not to grow spring beans. It is about changing the way people think.'

Take a holistic appproach

Farmers have been advised that the control of blackgrass should be part of a holistic approach to farm management, costings, rotation and nutrition – with the health of the soil central to everything.

Edward Downing, fertiliser technical manager for Frontier Agriculture, said: 'It is all about marginal gains. Nothing on its own will work.

'People are expecting someone to come out with some fantastic new chemical. We all want that silver bullet but it is not there. So you need to look at the basics to get it right.

'A healthier soil will have a crop that establishes better. In a dry spell it will hold water and in a wet spell it will drain better. The better that growing medium is, the better buffer you have against the weather and the better flexibility to deal with difficulties like black-grass. If you have got a better structured healthy soil with good organic matter and great drainage you can drill later because you can get on the land later than if you had poorly structured soil. So the whole ethos has to be around creating and improving good soil structures.

'Farmers should view black-grass as a fixed cost. No individual crop should have to pay for black-grass control. The farm should pay for it. Then you have a different attitude, you understand some crops will suffer and some crops will win.'

Five things learned about blackgrass this season

- Take advantage of the quick harvest to resolve drainage issues.

- Rotate everything: cropping, establishment, culture, nutrition, machinery.

- Get the seed bed right, and get the seed rate up.

- Delay drilling – hold your nerve.

- Don't be deterred from spring cropping by chasing a perceived gross margin.