Managing soils to improve physical structure and chemical and biological activity has become a key trend on arable farms this decade.

Each of this season’s Arable Insights farmer panel are prioritising soil management as a tool in their overall strategy, with the use of reduced tillage and cover crops common across the farms.

However, implementing a soil first approach is not without its challenges, and there are some crops or situations where alternative practices are being trialled.

See also: Arable Insights Farmers’ strategies to optimise nitrogen use

Richard Anthony – Companion crops in maize

That’s particularly the case for Welsh farmer Richard Anthony when it comes to growing maize.

The spring-sown crop is an important part of the rotation, but it can be one that is more damaging to soils, especially at harvest, if managed poorly or the weather goes against you.

“It’s not just harvest,” Richard says. “It can also be when you try to get the next crop established in challenging conditions.”

Taking inspiration from the success of growing companion crops with oilseed rape, he’s planning to trial a similar approach in maize, albeit with slightly different objectives.

In this case the companion will help protect the soil between the maize rows, supporting the weight of harvesting machinery better, while also improving soil structure so it’s easier to drill the next crop, he says.

Broad-leaved companion crop

The plan is to trial mixing in some broad-leaved companion crop options and possibly a small-seeded rye to avoid any negative competition from the companion for the maize.

“Maize is a lazy plant and doesn’t like any competition, so it is a big challenge to find something that will work,” Richard notes.

After trying inter-row drilling with little success, he plans to sow the companion when applying a second pass of digestate through a dribble bar, when the maize crop is about 15-20cm tall.

“I don’t know if it will work, there are some practical challenges, but we’re going to have a go.”

Barney Tremaine – erosion

At Cowdray Home Farms in West Sussex, a similar plan to trial growing companions with maize is being considered by Barney Tremaine.

Forage maize for the dairy enterprise and grain maize have become key crops for the farm.

“Maize grown well does a lot of good for the soil, putting a lot back.”

But erosion is a risk on the farm’s sandy clay loams soils, which has led to a strip-till approach for maize establishment to reduce soil movement, plus making sure fields are drilled in the best direction to reduce risk.

“We’ve also put some flower strips in fields to reduce erosion risk,” he says.

Like Richard, he has experimented with under sowing companions, using an inter-row hoe with a seeder, but without a huge amount of success.

“I think running through with a hoe started to dry the soil out, and by the time the companions started to emerge, the maize was shading them out.”

But last year, where maize was drilled, albeit as a high seed rate, with sunflowers tickled in with a Horsch tine drill at the same time, showed some promise, with the maize not showing any signs of competition.

“They grew well together. In theory, they should boost the protein and oil content in the silage without degrading the maize too much.

“I’m going to do another field like that this year to get a representative sample to analyse the feed value.”

Beans

He also trialled a similar approach with beans. “You have to be careful not to go too thick with either beans or sunflowers. They can compete for moisture in a dry spring, so it is a balance.”

An alternative approach could be to use drones to sow seed in the standing maize crop.

Again, trials last season showed some promise with a companion mix of clover, Westerwold grass and radish, particularly where the standing crop was thinner.

“The maize was already quite tall in July when we did this, so I think if we go a lot earlier, it will work better.

“It’s a case of doing lots of trials and seeing what works,” Barney concludes.

Charles Paynter – legume companion trials

In Bedfordshire, Charles Paynter is involved in innovative companion crop trials involving Anglian Water, growing three different legumes – subterranean clover, red clover and lucerne.

Cover crops provide increased diversity within his fields – one of the key soil health principles that drives improved biological activity in soils.

They potentially help reduce nitrogen use in a high priority catchment for nitrate water contamination.

“Anglian Water is helping to fund alterations to my drill, so each coulter body has two separate coulters, which allows me to drill different crops in alternate rows,” Charles explains.

“In the autumn I established in alternate rows a cover crop and a legume species in three 9m bouts across the field.

“The idea is in the spring, if it works, I’ll drill through the cover crop with spring wheat, while lifting the coulter out of the ground where the legumes are.

“Then I’m going to try various ways to control the legumes within the spring wheat crop.”

That could be achieved in a couple of ways – either rolling when the legumes are at a vulnerable growth stage or mowing, although the latter looks technically difficult, as well as more expensive.

Chemical mowing with a herbicide is another option – but Charles is keen to avoid using that option if possible.

Year one of the three-year project is mostly a feasibility study, he stresses.

“Is it practically feasible with the equipment I have as it relies on very accurate guidance and do the modifications to the drill work in practice.”

Philip Metcalfe – ryegrass leys

Being open to change is another common thread within the group. Philip Metcalfe started managing his farm with soils as a priority in the early 1990s on return from agricultural college.

“I wanted more resilient soils which were more forgiving. Back then our soils were very difficult in the wrong conditions.”

Initially the important pillars were using a greater proportion of organic manures after observing the most successful farms in the local area had that in common, plus reducing tillage.

But in more recent years he has started using over wintered cover crops and extended the rotation from three crops to eight in total.

This including bringing in herbal leys as well as more traditional cereal and break crops, some of which can be used in the farm’s animal feed business.

The two-year Italian ryegrass leys, in particular, are being used to give land in need of an organic matter boost, Philip says.

Grass isn’t the most profitable crop on the farm, but having tested organic matter levels for SFI, which range from 2.5% to 4.5% on the arable fields, he’s targeting the leys at fields with the most challenging soils and lowest organic matter levels.

A neighbouring livestock farmer buys the forage, which helps the economics, but Philip is already seeing visible, physical improvements in soil structure where the leys have been grown.

This despite it being too early to know whether it has increased soil organic matter levels.

John Farrington – introducing sheep

Somerset farmer John Farrington has made more extensive changes to what used to be until recently an arable-only enterprise.

He has brought in sheep to integrate into a system geared to regenerate a sandy, silt loam soil that had been overworked for several years.

“We had quite a lot of capping on headlands when there was heavy rain on light, erosion-prone soils, and all our straw was sold, with no organic matter coming back for 10 years,” he explains.

“It was obvious we needed to do something different.”

Something different included buying a second-hand Horsch Sprinter drill with low disturbance points to enable cover crop drilling, which was previously an expensive additional operation for the contractor used to drill crops.

That led to direct drilling of crops, while targeted subsoiling helped deal with historic compaction.

Organic matter is now returned via straw for muck deals, and like with Philip, John is incorporating herbal leys to rejuvenate arable soils that need a proper break.

“Those fields are likely to remain in the herbal ley for four or five years,” he says.

“We’ve used a slightly more expensive mix, with a lower ryegrass percentage and higher amounts of herbs and legumes, to give different rooting depths helping soil structure.”

The reduced ryegrass percentage, combined with high intensity rotational grazing by a flock of 700 sheep, helps maintain the herbs for longer.

“We don’t apply any artificial fertiliser, just rely on rest periods giving enough grass growth.”

In winter the sheep graze over wintered cover crops, which has brought into sharper focus species choice to make sure there’s enough dry matter yield to negate any grazing on the herbal leys over winter.

“When it was someone else’s sheep, we didn’t need the yield, but it’s now much more important,” John says.

“It means the soil health side is fighting the sheep side.”

The result is a mix of cover crop mixes, ranging from mixed species with Westerwold grass to give the potential for two periods of grazing over winter, to mixes dominated by stubble turnips.

Direct drilling spring crops is easier following the mixed species cover crop, while a low disturbance subsoil cultivation is sometimes needed following stubble turnips, John says.

“It’s highlighted the need to be flexible when you look at soils. When I first started this approach, I wanted to rigid and stick to the soil health principles, but actually you need to be flexible and be prepared to change.”

Doug Christie – species choice

Fife farmer Doug Christie agrees that flexibility is important when implementing soil health principles.

“I follow the principles fairly loosely a lot of the time,” he says.

“You have to think for yourself rather than expecting a blueprint – there is no blueprint.”

For example, growing over wintered cover crops ahead of spring crops is “low-hanging fruit” for improving soils, along with direct drilling or at least reduced tillage, he says.

But the nuance is in what that means for species choice, especially in Scotland, where the opportunity to establish covers in the autumn is small.

“It doesn’t have to be a fancy mix,” Doug points out. “Anything growing, even if it is just a few centimetres high is better than nothing, as the roots are still doing the business.”

Look at what species will grow in those autumn months, he advises.

“Even if it’s spinning barley, oats, beans or mustard on with a fertiliser spreader, they will grow in September and October.

“Obviously the later you sow, the less chance of a big cover crop, but I’m a firm believer that growing them punches above their weight in improving soils.”

Quantifying the benefits of not just cover crops, but all the changes he has made over the past 25 years is complicated, he says.

“I wish I’d taken benchmark soil cores to be able to compare, but improving soil health has given me the opportunity to reduce machinery costs and inputs considerably.”

Colin Chappell – low disturbance establishment

If there is one thing Lincolnshire grower Colin Chappell wishes he’d known before starting it’s that going “cold turkey” and trying to direct-drill a new block of underperforming land was likely to fail.

Egged on by his AHDB Monitor Farm steering group, he direct-drilled the most difficult field on the farm and immediately crashed yields on the 62% clay soil.

Although by the end of the four-year Monitor Farm cycle yields had recovered.

“Going cold turkey was a mistake, but I was challenged to do it, and I like a challenge.”

In the process, with the help of Ian Robertson from Sustainable Soil Management, he learned that low disturbance establishment on heavy soils needed to be implemented alongside other practices such as growing cover and catch crops.

Applying gypsum to help correct magnesium and calcium imbalances and using organic amendments, such as manures and composts, and biological additives like humic and fulvic acid, fish hydrolysates and molasses, were all vital.  

“It’s all about getting nutrient cycling,” he says. “And by giving the microbes something to feed on, you help unlock that and everything falls into place.”

At a glance: who are the Arable Insights farmers?
Region	Name	Address	Farm size
North	Philip Metcalfe	Caldwell, North Yorkshire	680ha
Wales	Richard Anthony	Bridgend, Glamorgan	1,200ha
South Midlands	Charles Paynter	Yielden, Bedfordshire	221ha
South East	Barney Tremaine	Midhurst, Sussex	1,280ha
East Midlands	Colin Chappell	Brigg, Lincolnshire	690ha
Scotland	Doug Christie	Leven, Fife	576ha
South West	John Farrington	Wiveliscombe, Somerset	243ha