Simple management changes can help make arable farming more sustainable – and often more profitable too, say analysts.

The environmental and financial performance of a typical 600ha arable unit (see “Farm facts”) was scrutinised by experts from Andersons Farm Business Consultants and farm software specialists Trinity AgTech.

Called Loam Farm, the hypothetical farm is located notionally somewhere in East Anglia.

As the name suggests, it has good loam soils and grows combinable crops. It has a working proprietor, one full-time employee and brings in casual staff at harvest.

Most day-to-day operations at Loam Farm are carried out in-house with minimal use of contractors. The farm is considered above average in terms of business performance, but would not be in the top quartile.

See also: Why regen farmer opted for a rotation with no break crops

“Loam Farm is a typical farm of its size,” says Richard King, partner with Andersons.

“The owners don’t have any goals as such – beyond perhaps being able to hand the business on to the next generation.

“Like many farmers, they don’t embrace or adhere to any particular farming system. Some people might describe them as doing what they have always done – and in that respect they are like a lot of farms.”

Analysts from Andersons and Trinity AgTech used Trinity’s Sandy software to assess Loam Farm’s sustainability – identifying four key areas for improvement, pinpointing potential ways to reach net zero and highlighting untapped opportunities.

1. Net carbon balance

• 2019 1,522t – 2.5t/ha
• 2020 1,197t – 2t/ha
• 2021 1,418t – 2.4t/ha

This metric measures the farm’s net carbon balance at a farm, field and product level. It is what we would expect for a farm with this sort of arable rotation, with average to low performance for crops of this type.

Yields are good for the soil type – and consistent, with average levels of fertiliser application. Spring beans are emitting less carbon than wheat and oilseed rape – because less nitrogen fertiliser is being applied.

Recommendations

Alasdair Sykes, Trinity AgTech

The farm has potential for more soil carbon sequestration. At the moment, most fields are sequestering about 50kg CO2e/ha, which could be improved. It is locking away some carbon, but the soil could do a lot more.

To achieve this, there are a number of options. I would recommend reduced and no-tillage. There is some reduced tillage already and expanding this across all crops would be a good thing.

No-till will give substantially more sequestration, but may be less practical.

The farm could also incorporate crop residues some seasons, rather than taking off straw year after year. It could also grow more cover crops and catch crops – and replace some of the fertiliser with organic manure, if doing so is possible.

A significant reduction in bagged fertiliser usage would be extremely beneficial – especially if yields can be maintained – or at least not reduced too drastically.

As an industry, we need to move beyond treating organic manure as a waste product. It should be seen as a valuable co-product.

Incorporating slurry and manure is soon going to be of significant value in terms of carbon credits.

Response

Richard King, Andersons

None of the recommendations are particularly scary. The farm has already reduced some tillage – there is much less ploughing now than 10-15 years ago.

But it is a gradual process rather than a matter of giving up the plough overnight.

Replacing bought-in fertiliser with manure is attractive but often harder than it sounds. It adds some complexity because of the variable nature of the product – manure isn’t always easy to come by in areas such as East Anglia.

The farm could retain more crop residue – but remember that selling straw is often a valuable source of farm income.

Whether the farm would be willing to relinquish that revenue would require some long and hard thinking.

2. Biodiversity

Biodiversity is a concept rather than a physical measure.

We score out of five, assessing the impact of farm practices across five key biodiversity types: farmland wildlife (1.5), conservation species (1.2), pollinators (1.2), natural enemies (3.2) and soil biodiversity (3).

The scores on Loam Farm are typical for a conventionally managed arable unit of this type with only a relatively small area of woodland.

At present, reduced tillage is about the only farming practice that is benefiting biodiversity to any extent.

Recommendations

Alasdair Sykes, Trinity AgTech

Reducing the amount of herbicides and pesticides would boost biodiversity.

This will increase the number of pollinators dramatically – depending on how widely any reduction in inputs is rolled out – and could even increase the pollinator score to 5. Both these recommendations will also help to reduce emissions.

Catch cropping, cover cropping and intercropping will increase biodiversity as well as having a positive effect on soil carbon.

Skylark and lapwing plots will boost the biodiversity score too, although without reducing emissions.

Response

Richard King, Andersons

We would like to be convinced of any financial benefits. Changing pesticide use is one thing – but we have an agronomy system that works for Loam Farm and we would be resistant to making wholesale changes.

Cover crops are a good idea, but again they are not without cost. They will be more attractive if they are eligible for payments under Defra’s forthcoming Sustainable Farming Incentive scheme.

It is the same for skylark plots, field margins and field corners. Like many farmers, we are open to introducing all these kind of things, but it is important we are adequately compensated for doing so.

3. Nitrate leaching

This measures the amount of excess nitrate that leaches from the subsoil and enters underground fresh water. At a farm level, Loam Farm is leaching 100kg/ha of nitrate.

We would consider this a little high, although there are no national figures to compare this figure against because it is a complex metric.

For any farm, it will be influenced by their location, soil type and the weather.

In terms of crop performance, spring beans are doing well at 80kg/ha, although winter wheat is less good at 129kg/ha.

Recommendations

Milad Toolabi, Trinity AgTech

Lots of mitigation options are available. But the most important way of mitigating leaching is optimising the timing and quantity of applications because crops require different amounts of nitrogen at different stages.

Farmers who use multiple applications rather than applying fertiliser in two or three bigger amounts will experience less leaching.

Organic fertiliser ensures the crop takes smaller amounts of nitrogen over a longer period which consequently can help in reducing nitrate leaching. Only some of its nitrogen is immediately available to the crop with the rest released over time.

It is well known that cover crops help reduce leaching. They are of increasing interest – including among water companies who are working with farmers to reduce pollution in watercourses.

So too is reduced tillage because less soil is disturbed.

Reducing leaching has a financial benefit – the more you reduce leaching, the more money can be saved.

Response

Richard King, Andersons

It’s a simple cost v benefit analysis. High prices mean everyone is looking more sharply at their fertiliser practices. Nobody wants to see fertiliser going down the ditch when it costs £600/t or more.

Timing applications properly to benefit the crop is important. But you have to fit that around the weather and the amount of land that you need to cover – so you are never going to hit the perfect spot every time on every single field.

That said, many farmers – and Loam Farm is probably one of them – look too closely at the calendar and not enough at the growth stage of the plant. I think that is an area where we should all pay more attention.

4. Nitrogen uptake efficiency

This metric measures the ratio of the nitrogen taken up by the crop to the total nitrogen available in the soil. Higher values mean a better job has been done in terms of optimising fertiliser applications. The range here is 21% to 72%.

Recommendation

Milad Toolabi, Trinity AgTech

Many of the recommendations to reduce nitrate leaching will also improve nitrogen uptake efficiency. The two metrics run in tandem.

A good example is using multiple applications at the right time, rather than applying larger amounts less frequently.

Incorporating fertiliser in the topsoil is also beneficial. Studies show that putting fertiliser where the crop needs it increases nitrogen uptake efficiency as well as reducing leaching – which again saves money.

Response

Richard King, Andersons

Using organic fertiliser rather than purchased ammonium nitrate is a good recommendation – provided that you can get hold of a good, consistent product. Availability and cost are key issues.

All these ideas are good. None of them are terrifying – it is more a case of them being good reminders of what we should be doing.

Marginal gains add up and that is what we are trying to achieve.

Conclusions

It is always helpful to put numbers on things – and this has been a useful exercise,” says Richard King of Andersons.

“The owners of Loam Farm are like all of us – they want to do their bit for the environment and reduce their carbon footprint.

“This will help them do that – and prioritise actions. Like a lot of challenges, it can be difficult to know where to start.

“You can’t do everything at once, so it is important to know where you can get the biggest bang for your buck.”

Many farms are too confused to know which direction to go – and Loam Farm is no exception, says Mr King.

There are many carbon calculators out there and so many different sources of advice that it is difficult to decide which is best.

Sandy measures more than just carbon, water and biodiversity, and the financial consequences of actions taken to mitigate emissions, says Alasdair Sykes of Trinity AgTech.

Increasing nitrogen use efficiency, using organic manure and introducing cover crops can make a big difference too.

“Those measures will take Loam Farm from being close to average to being a farm to be proud of – a beacon of excellence in terms of carbon sequestration and biodiversity – and good nitrogen practice, too.”