As featured in Arable Farming Magazine
An environmental route to a more stable rotation
by Arable Farming August 2020
Could taking whole fields for environmental stewardship de-risk some arable rotations, while providing returns comparable to some break crops? Mike Abram takes a look.
A desire to find alternative break crops to oilseed rape could provide the impetus for some growers to consider whole field environmental crops in the future.
Some options in the current Countryside Stewardship scheme stack up financially as well as poorer-performing oilseed rape and other break crops on some farms, suggests George Badger, a farming consultant and agronomist with
Strutt and Parker.
That could allow whole field environmental crops rather than confining stewardship measures to field edges.
“Bringing whole fields into arable rotations will increase the scale of environmental delivery on farms, while also giving a lower risk break crop for wheat,” he says.
What about black-grass control?
Some options also potentially allow growers the chance to reduce black-grass pressure.
AB15, for example, was designed to be used as part of a rotation to reduce blackgrass.
Within the five year scheme, you establish AB15 in year one of the scheme for two years before bringing the field back into the rotation, and then again in year three on a different field.
The legume fallow should be cut at least twice in its first year between March 1 and October 31 following sowing to stop black-grass heading. Cutting before the end of March in year two controls any remaining black-grass and it can then be sprayed off after August 15 before the area is cultivated for the following crop.
Other options are better in lower black-grass populations. Enhanced overwintered stubbles can be sprayed for black-grass and thistles after May 15, but the option is more beneficial for birds and insects where arable flora can set seed in late spring to early summer.
Four options (see table) could be suitable, he suggests, with AB15, a two-year sown legume ley, perhaps the most attractive.
“It provides the opportunity for a nitrogen-fixing ley in the rotation, so bringing soil health improvements to areas where livestock infrastructure or expertise no longer exists.”
Potentially, it could fit in a five-year rotation, with the two-year ley being followed by wheat, oats and wheat.
“Or to crop 80% of the farm, an alternative would be wheat, followed by an overwintered stubble [AB2], says Mr Badger, followed by a low input spring barley [AB14], then the enhanced overwintered stubble [AB6], followed by wheat then beans or oats.
“By preceding the enhanced overwintered stubble with spring barley, you should see a lower black-grass burden in the enhanced overwintered stubble.
“Deploying these options at a field-scale brings opportunities to create corridors of wildlife at a landscape scale between farms, but also a break crop for wheat.”
Any such decisions will need to stack up financially, he acknowledges. AHDB Farmbench oilseed rape gross margins from 2019 for the top 25%, the middle 50% and the bottom 25% of farms show the greatest range for any crop, highlighting the risk from growing the crop.
Mr Badger says: “So the Countryside Stewardship options of AB15 and AB6 have a comparable gross margin to the bottom 25% performance of oilseed rape, spring barley, winter beans, and to the middle 50% performance of a spring oats, linseed or spring beans crop.
“That said, if you are an above average performer for most break crops, then these options aren’t likely to give you a better gross margin, so these won’t suit all farms.”
However, the Countryside Stewardship option does offer increased consistency and a lower risk.
“These figures exclude any fixed costs savings, such as fuel or the opportunity cost of grain storage, or savings from collaboration with neighbouring farms, for example through combine sharing.
“But knowing your own costs and your own crop performance is key to making an educated decision about whether this will suit your farm,” Mr Badger says.
In the longer term, a farming system which delivers environmental and economic returns will be needed under the future Environmental Land Management
“So it makes sense to try and evaluate these options now under Countryside Stewardship to help make informed decisions in the future,” says Mr Badger.
Tool helps growers choose best environmental options on-farm
A tool to help growers choose between four environmental options on fields across Great Britain has been developed by the UK Centre for Ecology & Hydrology (CEH) as part of the Achieving Sustainable Agricultural Systems (ASSIST) project.
While many growers have access to precision map data for helping make crop production decisions, the same previously hasn’t been true for precise environmental data, says Prof Richard Pywell, science area head for biodiversity within CEH.
“The ASSIST e-planner is a simple, map-based tool which is designed to present the relative suitability of farmed land for different environmental interventions.
“It is free, web-based and covers Great Britain, and it is there to support farmer decisionmaking but not replace expert local knowledge of farms.”
The tool combines a range of factors, such as soil type, topography, habitat connectivity, watercourse proximity etc., that drive habitat restoration or intervention success.
“For example, if we want to create pollen and a nectar-rich habitat, it would work best on south-facing slopes on dry, freely draining soils, avoiding areas of
shade and where soils lie wet through winter,” says Prof Pywell.
These factors are translated into suitability maps for four environmental options – flower-rich pollinator habitat, water resource protection, woodland creating and sown winter bird food – which CEH believes will be important under the Environmental Land Management scheme.
To use the tool, Prof Pywell envisages farmers will begin by making an assessment of unproductive or difficult to farm land to take out of production, and then use the tool to compare the suitability of different environmental options.
It’s possible to either zoom in and draw a box around the farm area, or upload a GIS file of the farm’s fields. The data is then presented in four colour-coded
panels for each option as a heat map ranging from most to least suitable.
In addition, a traffic light system shows the regional priority for each option, he says.
“Once selected, the areas should be sense-checked for any local factors which the tool might not pick up on, and then monitored for success.”
A separate ASSIST e-surveyor app is being designed to help with the latter for sown pollinator or winter bird food mixes by using image recognition to identify whether species present are sown or weeds from a range of pre-loaded seed mixes.