Four rules to get the best SFI actions for your farm

A trials site open day sheds light on the best options for farmers

Farmers looking for the most suitable Sustainable Farming Incentive (SFI) options found help at hand during an autumn open day in Cambridgeshire.

More than 100 options are available under the expanded 2024 SFI offer – so choosing what works best can be tricky. Hence the Hutchinsons Environmental trial site demonstration kindly hosted by PF England & Son, near Warboys.

The theme of the day was “right option, right place” – highlighting the importance of targeting SFI options to individual farms and fields, rather than focusing solely on income.

Farmers were urged to look beyond the headline-grabbing payments on offer – some of which exceed £800/ha. Instead  careful planning can optimise benefits to the farm business – and mitigate any potential risks.

Rule 1 • Start with soil

Fully understanding soil health is an important first step in targeting the most appropriate SFI actions. This is especially so for soil management options, says soils services specialist Jade Prince.

“It’s only by looking at the bigger picture across the three pillars of soil health – physics, chemistry and biology – that we can identify any issues, then decide how to address them.”

While phosphate levels were generally high on the heavy clay soil at Warboys, much of that was being locked up and unavailable to plants because of a high pH – typically 7.5-8, according to a Terramap Gold analysis.

“We could use a cover crop containing buckwheat, which is a good scavenger of phosphorus in high pH soils, to help release some of that for following crops to utilise,” says Ms Prince.

Analysis also showed high magnesium content was causing a tight soil structure that was difficult to work. That was being rectified through the application of gypsum, SFI cover crops, and cultivations.

“If you don’t take time to understand what a soil needs and how it wants to be treated, that’s when trouble starts.”

Rule 2 • Select mixes carefully

Cover crops should be carefully selected, says agronomist and regional technical support manager Alice Cannon. Multi-species mixes should be chosen that best address specific needs.

The management and termination of covers also warrants careful consideration when deciding what to grow, she adds.

“White mustard, for example, is cheap, and can do a great job for soil structure given its deep tap root.

“But it has a high carbon:nitrogen ratio, which means that if it’s not managed correctly, there can sometimes be a yield loss in the following spring cereal as so much nitrogen is used by the soil biology to breakdown all that carbon.”

Every species has its pros and cons, says Ms Cannon. This means growers need to understand what is good and what isn’t to  fully to deliver any desirable benefits – both above and below ground.

Rule 3 • Super-charge soil biology

Trials at Warboys have highlighted another important consideration around multi-year stewardship mixes which contain a high proportion of legumes.

Work by Hutchinsons suggests that the sudden release of natural nitrogen which builds up in root nodules over a four-year AB15 grass-free legume fallow can act as a “super food” for soil biology, says technical manager Dick Neale.

A stewardship mix containing vetch, clover, sainfoin, lucerne and others, for example, prompted a spike in consumption of organic matter, that in turn, caused soil aggregates to collapse.

“Soil aggregates form around organic matter, so when that is consumed, the structure collapses, causing soil to become tight,” says Mr  Neale.

“The soil’s not compacted, and is still in good condition, full of roots, with decent infiltration, but it needs to be managed carefully to open that structure back up.”

At Warboys, that was done with gypsum application. “High mag soils are prone to becoming tight, but the issue we’ve seen with nitrogen release and organic matter consumption, seems to affect all soil types.”

Interestingly, no such structural issue was observed after the four-year AB15 mix containing grass, as the grass utilised nitrogen throughout the cover period, meaning no sudden spike in availability when it ended.

“You wouldn’t want to introduce something like ryegrass into an arable rotation, but, as many growers are utilising CNUM3 legume fallow on a one year basis, it may be that including wheat, barley, or triticale, within a legume fallow mix could help utilise nitrogen better and maintain good soil structure.”

Rule 4 • Consider weed burdens

Winter bird food on arable land (CAHL2) is  of the highest payments on offer under the SFI. It is worth £853/ha/year for three years.

“It is one of the best-paying options, but be really careful when deciding whether it will work on your farm,” says environmental services specialist Hannah Joy.

The option can be very effective on field margins, awkward corners, or as a spring-sown option on areas where crops had failed, but caution was needed when considering it on a field scale, particularly on more weedy sites, she says.

“Once you’ve drilled the mix, there’s little or nothing you can do in terms of weed control, so you need to be really careful it doesn’t create a mess that needs tidying up before that land can go back into crop production. Recognise the risks and do what you can to manage them.”

The same applies to other options, such as the legume fallow (CNUM3), which despite being badged by Defra as a way of helping to control grassweeds, is likely to do very little in that respect.

It can even exacerbate problems if not used appropriately, adds Hutchinsons tehchnical director Dick Neale.

“A lot of growers looked at the one-year fallow [in SFI 2023] as an alternative break to oilseed rape, but again, you need to recognise that once a legume mix is drilled, you’re locking yourself out of using any grassweed chemistry.

“The guidance suggests mowing can help control black-grass, but in reality, we often find it just sets heads a lot lower down, so still returns seed.”

Mr Neale insists that legume fallows can deliver many benefits to the soil and biodiversity. But he says the risks must be considered – and options targeted to individual situations.