Putting agroecology practices in focus

Another focus is the use of ‘biologicals’ to build soil health and crop productivity. Mr Brown says there is much hype around their potential, but little reliable information about effectiveness in real-world situations, something the Helix team is addressing.

A field of mid-October-sown wheat – a home-saved blend of Crusoe, KWS Extase, Gleam and Costello – has been split in two, with one side as the untreated control, while the other half received biological additions at drilling. This took the form of a liquid inoculant, extracted from compost produced using a Johnson-Su Bioreactor, and applied either in-furrow on the drill, or as a seed coating.

Analysis of the compost showed it was high in beneficial microbes, protozoa, saprophytic and mycorrhizal fungi. “These are all things we’re trying to build in the soil, so we tried to create an effective inoculant,” explains Mr Brown.

Satellite imagery this spring identified that the untreated area actually had higher above ground biomass, while analysis of root biomass showed it was 78% greater where the biological treatments had been used.

Full and half-rate nitrogen trials across the same field also showed a positive response where the compost extract had been used.

“It’s still early days, but hopefully the biological treatment should produce more resilient plants and better yields, but we’ll see what happens at harvest,” Mr Brown says.

Cover cropping is crucial to the rotation on the light soils at Whitley Manor, with Mr Heath aiming to establish a cover or catch crop on every field each season.

While there is much focus on their value for building soil structure and preventing erosion, he is keen to better understand what cover crops can also deliver in terms of nutrition to following crops.

Plant nutritional assessments of one eight-way Maxi Cover mix by Mr Robertson last season showed it contained 107kg N/ha, and available nitrogen in the following crop of poppies was increased by around 30 kg N/ha, compared with an area of no cover.

“For a £40/ha cover crop cost, there is a clear financial benefit from nitrogen alone, before you even consider any other nutrients or soil health benefits.”

Mr Heath says greater use of cover/catch crops has also been the gateway to having more outdoor livestock on the farm, although he acknowledges more work is needed to identify the optimum timing and method of destruction. Grazing, rolling and crimping are all being considered as alternatives to glyphosate.

One of the big challenges at Whitley Manor Farm is resistant ryegrass, which initially migrated into one field from the margins, but gradually spread elsewhere. Controlling ryegrass now dictates many cropping and management decisions.

“Italian ryegrass is a real beast when it becomes resistant, and as populations become resistant to residual herbicides, it gets harder to control,” says Hutchinsons technical manager Dick Neale.

Testing ryegrass to determine what herbicide chemistry it is susceptible or resistant to should be a priority, and here commends doing multiple tests across the farm, as the resistance profile can vary from field to field.

“It’s important we do testing and only apply products we know will work,” agrees Mr Heath. “Although there are new options like Luximo (cinmethylin) available, we need to use them responsibly and can’t just jump in thinking they’re the saviour.”

Given the ability of ryegrass to grow in almost every month of the year, and a significant germination period from April to June, growing spring barley, as many do for black-grass management, is unlikely to be as effective for ryegrass, Mr Neale points out.

Minimising seed return is key, and with that in mind, last harvest Mr Heath tried using a chaff liner on the back of the combine to catch ryegrass seeds coming off the sieves and concentrate them into a narrow band behind the machine.

The relatively low-cost system proved effective in catching seed, with distinct bands of weed growth visible this spring.

However this extra competition did cause spring barley in the following barley/peas intercrop mix to struggle, whereas interestingly, the peas eventually dominated the ryegrass.

“By summer, there was hardly any ryegrass visible,” says Mr Neale. “It’s not entirely clear what’s happening, but maybe peas are more competitive than we think.”

Strict harvest biosecurity is also important, and Mr Heath ensures the combine is thoroughly blown down before moving fields to reduce the risk of spreading seed. Shallow ploughing has also been introduced to bury seed where there has been high return.

Maintaining a diverse rotation, that includes competitive catch and cover crop mixes, and six-row hybrid barley, is another tool to help suppress weeds, he notes.

All of Mr Heath’s winter wheat is sown as a four-way blend of home-saved Crusoe, KWS Extase, Gleam and Costello. These varieties were chosen to maximise genetic diversity as there is no shared parentage, notes Mr Brown.

“The blend might not necessarily beany cleaner than the latest variety, but it does provide more persistence from mixed genetics.”

Indeed, observations this spring suggest there was noticeably less Septoria in the blend, in what was a relatively high pressure season. It is hoped this will help the farm maintain average yields that are at, or above, the UK average, but from a relatively low input system.

Results from nine other farms growing wheat blends last year found on average, yield was 0.2 t/ha higher than with a single variety, and total fungicide spend was slightly less, albeit 2022 was a low disease year, Mr Brown notes.