Herefordshire-based Micron Group's latest Varidome S3 band sprayer, commercially launched earlier this year, means "we can now supply glyphosate between rows four inches wide", said Richardson. This is achieved thanks to novel spray shields that prevent the spray from coming into contact with the crop, he explained.
An electrical inter-row weeder is now under development by Ubiqutek, he added. The West Midlands-based developer has so far focused on amenity weed control but is now adapting the technology to agriculture as part of the EU's Horizon 2020 programme, it was announced last week.
With funding from AHDB Horticulture and the Government, Garford Farm Machinery of Peterborough has developed a vision-guided inter-row band spray combined with spot treatment for in-row weeds, said Richardson, who also co-ordinates a number of AHDB Horticulture industry projects.
Exhibiting at the show, Garford's export sales manager Chris Lunn told Horticulture Week that the company's latest all-electric weeder, due to be launched next season, "uses less energy per row and has a higher work rate of six plants per second", and explained: "Unlike valves, the electric activators work instantaneously, so in theory at unlimited speed."
But uptake of such technologies can only happen "when the market is ready", he said. "In general, farmers still have the chemicals in their armoury, especially for field vegetables. But as these disappear we have a solution ready that uses a fraction - around 10 per cent - of the chemicals they would otherwise use."
He added: "We can also use broad-spectrum herbicides like glyphosate in onions, leeks, carrots and parsnips - the regulators understand what we are doing. Unlike with selective herbicides, you are using low amounts of low-cost materials."
Harper Adams University head of engineering Professor Simon Blackmore, a long-standing proponent of on-farm automation, said at the conference: "A weeding robot to replace chemical spraying altogether will be a 'killer app' for field robotics. But it's frustrating that what we are doing isn't being picked up. It's a disruptive technology and that puts people off. It will benefit the industry but the industry has to go through a pain barrier first."
HAU, Syngenta, the University of Manchester and G's Fresh are currently in the middle of a three-year project to develop a system to visually recognise the growing tip of weeds and then apply either a laser shot or a "microdot" of herbicide.
Beyond this, he explained: "I am developing the concept of small, smart machines to make the whole crop production system more efficient. There's no point in just building one machine - you need a modular system to establish the crop, scout to detect agronomic needs, control weeds and then harvest it selectively."
A combination of such ultra-light machines and "controlled traffic farming" would eliminate the problem of field compaction caused by ever-larger machinery, he stressed. "If you don't need traction, you don't need weight. And if you leave the soil alone, the natural flora and fauna will create soil structure by themselves."
Jake Freeston, who runs a mixed farm on the Gloucestershire/Worcestershire border, said his Nuffield scholarship has enabled him to study no-till arable and vegetable growing systems elsewhere in the world, including a farmer in Oklahoma, USA, who has practised zero-tillage for 20 years and now has a soil structure and organic content completely different from that of neighbouring farms. "It was a light bulb moment," said Freeston. "Disturbed soil also allows weeds to germinate."
Even potatoes can be grown without soil disturbance, as examples in the US show that tubers will grow if left on the surface and covered with straw to prevent greening, he said, adding: "Imagine the cost savings."
Meanwhile, cover crops create drainage channels in the soil, while grass "is fantastic at removing shallow compaction", he said. He also urged growers to consider the benefits of crop rotations including grazing livestock on cover crops, saying: "You guys are in a strong position to increase crop rotation, including spring cropping."