Putting solid science into regenerative regimes

These are just some of the questions which the latest series of Green Horizons trials run by Agrii and key initiative partners with innovative growers across the country seeks to answer.

At Little Babraham just outside Cambridge, for instance, two very different feed wheats are being grown at scale with a variety of crop protection regimes in neighbouring light land fields under the extremes of cultivation practice; work that is being paralleled on heavier ground on the Bedfordshire border and Dorset downland.

Reduced tillage approaches

“Regen experience is growing in leaps and bounds as more growers explore reduced tillage approaches,” points out Agrii seed technical manager, John Miles (right) who is co-ordinating the work. “And escalating diesel, fertiliser and other costs are fuelling progressively wider interest, driven by economic as much as environmental sustainability imperatives.

“Much of today’s experience, however, comes from trial and error, is highly individual, and extremely anecdotal. This leaves those moving to more regenerative practices facing far too much risk for comfort in an increasingly uncertain world.

“Alongside our long-standing national and regional variety trials, we have set out to characterise any varietal behavioural differences and establish how to make the most of them in more regenerative regimes. That way, growers can do so with confidence and without having to find out for themselves the hard way,”  he says.

Variety behaviour

The variety behaviour trial at David White’s Hawk Mill Farm, on land in its seventh season of no-till management, and a neighbouring Wilbraham Farms field within a stone’s throw of it that continues to be ploughed annually, involves popular feed wheat Gleam and Graham successor, Fitzroy as third cereals.

With almost identical high pHs and sandy silt loam soil analyses, the two fields were sown with half hectare blocks of both varieties on the same day last October with drills suited to their particular conditions. While the traditionally-managed ground had a soil organic matter of just 2.9% and Lancrop Soil Assessment Score of 51, the regenerative field analysed at 4.2% organic matter with much higher biological activity levels, giving it a score of 70.

As well as its popularity, Gleam  was chosen as being representative of rather slower spring developing types with relative rust weaknesses. This contrasts with Fitzroy’s particularly vigorous growth habit and across-the-board disease strength.

A total of 20 different disease management regimes with established and new chemistry at full and reduced rates and a variety of promising biologicals are being applied across the fields and varieties to investigate both their overall and particular regime value.

Complete analysis of almost every aspect of crop growth, development, nutrition, disease from establishment through to harvest yield and quality are allowing all performance differences to be characterised in detail.

Single step from full- to no-till

Mr White, who switched his field’s cropping from spring oats to accommodate the trial, is no stranger to experimentation, having worked with his Agrii agronomist, Matt Clark (right) to investigate a whole host of regenerative options since making the switch from full to no-till in a single step in 2016.

“We’ve been able to improve our soil health, moisture holding capacity and workability well in this time by moving as little soil as possible, growing more spring crops, maintaining near to year-round green cover and improving our residue management, amongst other things,” he explains.

“A good £1,200 in diesel to fill up a big tractor is certainly concentrating the tillage minds of many more growers this season,” points out Mr Clark. “But shifting from a tried-and-tested establishment regime to a new approach involving little or no tillage isn’t all plain sailing. Especially on heavier ground, where grassweeds are problematic, and as far as residue management is concerned.

“On our own farm in Essex as well as with growers I work for across East Anglia, we find the most fundamental essential to success with reducing tillage is getting the drainage right first and keeping it right; even if this means a little metal at depth whenever necessary to get rid of compaction. Fail to do this on heavier ground or soils with much in the way of silt content and things can go badly wrong very quickly.”

Bringing elements together

Both Mr Clark and Joe Martin, field technical manager with key Green Horizons trial partner, Corteva routinely see some crops and varieties doing better than others under reduced tillage and lower input regimes. But they agree there is nowhere near enough understanding about which and, most importantly, why. Is it down to relative robustness, competitiveness, nutrient utilisation efficiency, disease and pest resistance or tolerance, or what?

“It will be fascinating to see the results of this and the other Agrii trials we’re involved in,”

Mr Martin says. “Ironically, perhaps, after years of focussing its attention on varieties that are most responsive to inputs, what farming really needs for a more sustainable future is those that are high-performing but least responsive to input reductions – whether intentional or as a result of climatic extremes.

“Cropping abilities here are, of course, bound-up with soil and plant health as well as genetics. And we’re exploring a growing range of nutritive and other bio-solutions in the trials, in addition to highly effective new fungicide chemistry like Questar (Inatreq).

“We want to know how to bring all these elements together in the most cost-effective variety-specific agronomy programmes for different regimes. What will work best, when and where. This is particularly important with biologicals which are noticeably less consistent in their activity than most crop protection chemistry in our climate.

“The Green Horizons studies are a hugely valuable resource in helping us fine-tune our contributions to a more sustainable future alongside those of the plant breeders, crop nutrition, tillage and soil specialists. There is so much more we all need to learn here.”