Farmers in East Anglia are being encouraged to join a growing movement towards spring cropping as a means of battling black-grass – and they have been urged to measure the risks against the rewards.
The battle against black-grass has become a constant thorn in the side for many farmers – particularly as its resistance grows to a dwindling arsenal of weedkillers.
Moving from winter-sown to spring cereal crops is seen as one of the best ways to solve a runaway black-grass problem, by creating a window of opportunity to get grassweed seed banks under control.
But delegates at a farming seminar in Norfolk were told that while this approach can bring rewards, it also comes with the massive challenge of rushing the required water and nutrients into the crop in a much shorter growing season.
The subject was discussed at Frontier Agriculture's 3D Thinking conference, held at the John Innes Conference Centre on the Norwich Research Park.
After hearing how the company's trials site near Newark had proven how spring cropping had brought substantial improvements to fields infested with black-grass, delegates were told the extent of the task facing them if they wanted those crops to be successful.
Edward Downing, Frontier's crop nutrition and technical manager, said if farmers were aiming for a profitable yield of 8t/ha (tonnes per hectare) for spring barley and 8.5t/ha for spring wheat, their water requirement would be 267mm and 288mm respectively.
Given the 30-year average for that timescale in the region was less than 200mm, he said soil structure and root growth had to be the farmer's priorities.
'200mm of rain is only good enough for a crop of 6t/ha,' he said. 'So clearly if we are going to achieve yields of seven or eight tonnes that crop has got to access the rainfall of previous months.
'What this is all leading to is if we want to achieve high yields from spring crops we have to get the best roots we can, and have them proliferating as deeply as possible. We have got to have decent seed beds but most importantly we need excellent soil structure.
'It is always worth taking a spade out and checking the root depth of previous crops. 50mm less water that is not captured by your crop could mean 1.5t/ha is wiped off your yield.'
Mr Downing said the challenge was just as great for nutrient uptake. He said nearly all spring crops would benefit from a an application of fresh phosphate as a 'shot in the arm' to establish the root system quickly, while nitrogen and sulphur were the 'yield drivers'.
He said 252kg of nitrogen would be needed per hectare to achieve milling quality wheat at 8.5t/ha, and the timing of the applications was vital – with trials suggesting applying 30pc to the seedbed and splitting the rest across two separate growth stages could boost yield by almost 0.5t/ha.
'I want to get people thinking differently about spring cropping,' he said. 'The point I am trying to get across is that often we treat spring crops in the same way as winter crops. In terms of the quantity of nutrition uptake they are not dissimilar, but winter barley will already have a root system of a metre-plus established by Christmas, while the spring barley is still sat in a seed bag. They have got to take up the same amount, but this has all got to happen in an incredibly short time.
'So we have got to be even better at establishing a spring crop than a winter one. It is like a sprint rather than a marathon, so the condition of the soil for spring cropping have got to be much better.'
According to the Early Bird Survey published in November by the Agriculture and Horticulture Development Board (AHDB), the area planted to spring barley is predicted to be 17pc higher for harvest 2017 than harvest 2016.
Mr Downing said the main driver for the change was blackgrass-ridden farms in the Midlands and Lincolnshire, but there has also been a big switch from winter barley to spring barley across East Anglia.
'I would say in Norfolk and Suffolk there has not quite been the 17pc, but we have got farms which were historically 70-80pc winter cropping that are now more like 50/50,' he said.
'We don't have the same black-grass problem here that they have in Lincolnshire, so we are further away from the cliff. But we want to avoid getting nearer the edge of that cliff.
'We have always been good as an industry at delivering solutions to farmers' problems,. But now, whether it is because of regulation or pure cost, the industry is struggling to find those solutions quick enough. In the past there was too much reliance on there being a 'silver bullet', but we need to move farmers' attitudes and say there are a number of factors that can bring control.'
Risk versus reward
Spring cropping was just one of the options discussed at the conference as a means of combatting black-grass weeds.
David Robinson, Frontier's head of trials and innovation, outlined the results of trials conducted at Staunton near Newark, where unaltered cereal plots were compared against blocks with rotational ploughing, minimum tillage, direct drilling and growing rye as an energy crop.
He said all these methods had successfully reduced black-grass numbers.
'One thing that is clear is that change is essential if there is a black-grass problem,' he said. 'If someone is on a traditional winter rotation, doing nothing is not an option.
'The least you can do is to change the cultural methods you are using on the farm, and the most effective way to do that is to go to spring cropping. That for some people is quite a big step.
'The whole point of this is to give people the confidence that going into spring cropping is not financially difficult.
'There are two categories of people. There are those who are already doing it, and then those who I call 'reluctant adopters', who will always find excuses for why it wouldn't work.
'The main criticism is: What if it is a wet spring and I am delayed? We don't want to drill early because we want as long a break as possible to get as much germination of black-grass as possible (so it can be destroyed before the spring crop).
'If the weather dictates that the drilling is later than optimal, then your yields are likely to be less. But you need to focus on why you are doing it, and that is to go from an unsustainable level of black-grass to a sustainable farm, and you may need to be prepared to accept some short-term pain for long-term gain.'
Is your farm considering changing its rotation to combat black-grass? Contact chris.hill@archant.co.uk.
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