Finding a reliable break crop in the arable rotation is an ongoing challenge.

Sustainable Farming Incentive (SFI) actions, such as herbal leys or legume fallows could be an alternative, especially where livestock can be added to the rotation.

AHDB analysis has examined a set of farm scenarios where winter oilseed rape and winter beans are replaced with SFI actions herbal ley (SAM3, £382/ha) or legume fallow (NUM3, £593/ha).

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The analysis was modelled using the AHDB’s 455ha “virtual” arable farm.

The model farm was designed to be representative of “typical farms”, fitting within the middle- 50% of performing businesses.

The analysis assumed herbal leys were carried out as a rotational action (which would be expected if it was to replace oilseed rape or beans).

The modelling did not include additional income from livestock grazing.

Overall, the net profit of the farm falls over the three years, due to progressive reductions in direct payments. All other variables, such as prices, were kept constant over the three-year duration.

The analysis examined the effect on the farm’s net profit if the area used to grow 31.5ha of winter rapeseed and 36ha of winter beans was replaced with either a herbal ley (SAM3) or legume fallow (NUM3) action.

Three scenarios were assessed with varying break crop yields: average yields, below average and complete crop failure.

A price of price of £413/t was used for the oilseed rape, and £211/t for the winter beans in each scenario.

Winter oilseed rape

Scenario 1 – Average rapeseed yield of 3.28t/ha

In all three years of the agreement, the net profit of the farm was the highest when average-yielding winter rapeseed was grown.

The legume fallow was the next best option out of the three choices shown − herbal ley was the least profitable decision.

Scenario 2 – Below average yield of 1.5 t/ha

Under Scenario 2, the net profit of the arable farm was highest with an SFI legume fallow.

However, the increase was modest, at around 1%. If an SFI herbal ley was grown instead of winter rapeseed, the net profit of the farm would be around 4% lower.

Scenario 3 – crop failure

“In the event of a failed rapeseed crop, there is no doubt that the SFI legume fallow or herbal ley would be considerably better alternatives, as they would at least provide the farm with some income,” reports the AHDB.

The net profit of the arable farm would be around 9-10% higher if an SFI herbal ley replaced winter rapeseed over the three years.

If an SFI legume fallow was grown instead, the net profit would be around 14-17% higher.

Young oilseed rape plants damaged by flea beetles © Tim Scrivener

Winter beans

Scenario 1 – winter beans yield of 3.68 t/ha

Replacing a winter beans crop with either SFI herbal ley or legume fallow would reduce the net profit of the farm.

In this scenario, keeping winter beans in the rotation was the best option for the farm in terms of obtaining the highest net profit.

Scenario 2 – winter beans yield of 1.8 t/ha

Replacing a winter bean crop with an SFI legume fallow makes a negligible difference to the 455ha arable farm’s net profit.

Replacing winter beans with an SFI herbal ley would result in a 5-6% decline in the farm’s net profit.

Scenario 3 – winter beans crop failure

The AHDB states: “Unsurprisingly, as an alternative to a failed winter beans crop, both SFI herbal ley and legume fallow are better options.

“The 455ha arable farm’s net profit would be 6-7% better off with an SFI herbal ley compared with a failed winter beans crop and 12-14% better off with an SFI legume fallow.”

Is it worth replacing break crops with SFI actions?

If break crops consistently fail and offer little return, then SFI actions, such as a herbal ley or legume fallow, may offer a better alternative in terms of a source of “guaranteed” income.

Not only this, herbal ley options invites the possibility of introducing livestock into the arable rotation, which can bring in further revenue to the arable farm and opportunities for those looking to get on to the farming ladder with grazing lets.

Legume fallow (NUM3), however, cannot be grazed by livestock. This may have implications for grassweed control going forwards and other long-term issues if not managed appropriately, which should be taken into account.

The AHDB states its key findings from the analysis below:

• From a financial perspective, it is only worth replacing break crops with an SFI action of planting a herbal ley or legume fallow if they are prone to consistent crop failure
• Only replace break crops with herbal leys or legume fallows when they can be established effectively and have a positive effect on the wider farm
• Do not make decisions based on circumstances in one isolated year – an SFI agreement is for three years, so it is important to take a multi-year approach
• Price volatility is an inherent feature of agricultural commodity markets – the SFI can act as a stable component of farm business income and will be especially important under challenging market conditions.

Spring beans © Tim Scrivener