Compaction is one of the biggest influencers on soil health. As such, reducing its impact on crop growth is of paramount importance to all growers. Geoff Ashcroft investigates several compaction-reducing techniques being employed on-farm.
There are many different aspects involved in managing soil compaction. Tyre choices, inflation pressures, the use of rubber tracks and the routes taken by in-field traffic, all have an impact on how soil responds to weight and pressure. In addition, cropping choices and tillage regimes all play their part when it comes to overall soil health.
Soil damage significantly reduces the uptake of essential nutrients, leading to run-off and, with it, erosion from heavy rain. In such situations, it becomes essential to aerate the soil, allowing water, nutrients and air to pass through the profile. Though, avoiding compaction in the first place can be far less costly than having to repair it.
To find out more, we spoke to three growers, all taking different approaches to managing and reducing compaction.
For one Somerset grower, the use of strip-tillage could hold the key to managing compaction, as a result of improving harvesting conditions in maize.
Dillington Estate near Illminster, Somerset, grows 200 hectares of maize within a 660ha rotation with potatoes, cereals and grass, to provide the high-energy forage crop for local AD and livestock customers.
“While the primary goal of strip-tillage is to seek a reduction in establishment costs, I can also see a benefit with compaction management too,” explains farm manager Ollie Blackburn. “And that is important with late season harvesting, when conditions under-foot can be less than ideal.”
Having trialled direct drilling to establish maize for the last four seasons, Mr Blackburn has now shifted the establishment process to strip-tillage, using a Kverneland Kultistrip.
“Our direct drilled maize approach revealed that we really do need to move some soil and carry out deep loosening in preparation for precision planting maize,” he adds. “But we do not want to move all the soil, and this is where strip-tillage can provide some tangible benefits for growing maize.
“This is only our second season with strip tillage, and we are currently running several different trials across the farm to find the most effective method of soil preparation for maize,” he says. “By not moving much ground, weed growth will stay suppressed and our cultivation costs could be reduced by up to 50%.”
The six-row, 4.5m hydraulic folding Kultistrip arrived at Dillington Estate for the 2020 season and gave opportunities to explore the principles of reduced cultivation. Working to 750mm row spacings, the machine moves a 150mm strip of soil, leaving 600mm of land untouched between the rows.
“By leaving strips of ground untouched will maintain a firm surface for the forager and trailers to run on. And that means less mud on the road and hopefully some easier harvesting conditions. In turn, I am expecting to see less of an impact on soil health and compaction in all our maize fields.
“We are also putting cover crops in after potatoes and ahead of maize, to keep soil biology alive,” he says. “Spring slurry goes on our maize ground, ahead of strip-tillage and drilling. And with glyphosate used in a pre-emergence tank mix, we can leave a mulch on the surface that helps to retain moisture.
“Depending on the season, if I have to make two or three repeat passes over the strips, it will still be a considerable cost saving compared to traditional deep cultivations,” says Mr Blackburn.
Running the Kultistrip at 280mm deep, soil is loosened and the surface is stripped clean ahead of being crumbled and firmed by rubber press wheels, ready for drilling. The farm’s older six-row mechanical drill is supplemented by contractor services with a wider eight-row unit, with GPS and auto-steering used to provide pass-to-pass accuracy.
“Working at 11-12kph on a 150hp tractor, we can soon cover a lot of ground with the Kultistrip,” he says. “There is a lot of untapped potential in this system, which could also help to establish maize after grass. This could be a huge benefit to growing this energy crop, without compromising on soil health.”
A mechanical approach to managing compaction is being taken by Michael Balls, arable manager at Albanwise Farming’s Hill Farm, Barton Bendish, who has switched from tracks to tyres to make the most of operational flexibility.
“We moved to a pair of Fendt 1050’s three years ago, replacing twin-track crawlers,” he says.
“While the tracks were always viewed positively for managing compaction, we have now eliminated scuffing on headlands by going back to tyres.”
He says that big improvements in tyre technology to handle higher horsepower, and the introduction of Fendt’s VarioGrip on-the-move central tyre inflation system, has been a revelation.
“VarioGrip is a game-changer,” says Mr Balls. “Though, we had to look at things differently and open our minds to the many different options available. Part of this process is having your operators on-board with you.”
He says that there are parameters built into the on-board computer system for weight and load, to help the team make the most of tyre performance, traction and power.
“We tend to use 1.6-1.8 bar for road transport and 0.9-1.1 bar for field work – though it all depends on the job being done, and how much ballast the tractor is carrying.”
He says it takes about 15 minutes to switch between road and field pressures, and to keep non-productive time to a minimum, the last pass around a field headland is an ideal opportunity to start the tyre inflation process.
“By the time the drill has been folded up and the tractor pulls out of the gateway, the tyres are inflated to operate at up to 60kph,” he adds.
The 3,600ha farming business handles a wide variety of crop types and uses the two Fendt 1050’s for frontline cultivation and drilling. Cultivation strategies are chosen to suit cropping, soil types and weather conditions.
“Had we stayed with rubber tracks we would have needed an extra tractor, to do the jobs where you would not want to use the crawler,” he says. “Putting a 500hp wheeled tractor on a trailer, is not such a big deal, nor is road work.”
Importantly, the farm has a wide range of weights available for its tractors, including 3,300kg front weights and 1,200kg wheel weights specifically for the two Fendts. Operating weight can be adjusted from 16 up to 22 tonnes.
“Swapping weights is easy and the tractor has surprised me with what it can do without any weight,” he says. “If conditions allow, we will try drilling without any front-end weight this season.
“It does mean we can be considerate when it comes to managing compaction, and when it is so easy to adjust pressures, the job gets done to a higher standard.”
In-field traffic management is something that Oxfordshire grower Ben Smith is increasingly aware of, with his fleet of high-capacity, high output kit. He runs on 40m tramlines, with 13.3m intermediate wheelings across the 2,000ha he farms from Manor Road Farm, Wantage.
In the last few years, he has noticed a positive change in soil texture, with the top 50mm becoming much more friable, and able to accept a more direct approach with cultivations and seed placement.
“Worm activity is impressive, soils are restructuring and we have not needed slug pellets since 2019,” he says. “Natural predators are working for us.”
Improvements seen from CTF and min-till practices from 2014-2018 encouraged the farm a step closer to direct drilling. And three years into using a Dale Drills Eco XL grain/fert no-till drill, he says there is no going back.
“We are now adding a Horsch Avatar, to provide a disc option for those areas that can take a reduction in soil movement compared to the Dale Drill’s tines.” he says.
When it comes to harvesting, trailers stick to tramlines and a pair of Lexion combines with 13.5m headers follow the wheelings of the drill.
“We are at a stage where the drill needs less and less power to pull because our soils are naturally repairing. We only sub-soil any deeply rutted tramlines and any compacted intermediate wheel marks ahead of drilling, on a field-by-field basis,” he says. “CTF has delivered huge improvements across the farm.”