Hold the front page! Mixed farming is the only long-established sustainable farming method on arable land.

The good news is, we don’t need to do any trials on this – 175 years of testing in sandy loam at Woburn experimental farm, connected to Rothamsted Research, has proved beyond any doubt the only way to avoid depletion of carbon in soil is three-year ley and three-year arable. Who knew?

Many thanks to Adam Christie, of Scottish Agronomy, for bringing this up during an excellent presentation at the SAOS conference, last week, which focused on carbon and climate change.

Couple that with observations from Mike Robinson, CEO of the Royal Geographical Society and co-chair of Farming for 1.5°, who pointed out that the proper metric for methane is not being used. It is being treated as a long-term gas when, in fact, it is a shorter term one in agriculture.

That doesn’t necessarily mean we get completely off the hook, but it left me thinking we are trying to build future rural policy on the wrong foundations.

If you’re a government who genuinely wants arable farming to meet its legal commitment to 31% reduction in greenhouse gas emissions from 2018 levels by 2032, what are the ways in which that might be achieved?

Firstly, regardless of the substantial fertility benefits, the only tried and tested way to maintain and soil organic matter, ie carbon, is to have grass and clover in your rotation. Cover crops and no-till/min-till can certainly help with nutrient retention, biodiversity and soil stabilisation, but they are just tinkering around the edges as far as locking up carbon is concerned.

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The Woburn trials clearly show that arable land without grass in the rotation is not ultimately sustainable, especially if you regard maintaining soil organic matter as important. This was made quite clear to all of us when we discussed all of the options in the Arable Climate Change Group in 2021.

Why is it not the first and last priority for arable land in policy discussions?

A century years ago, almost all arable farms would have had grass and livestock on them, but we have got out of the way of it. Once the cows went off a farm they were very unlikely to come back and government policy won’t support it because they are wedded to the wrong measurements for methane.

You could be forgiven for becoming a bit cynical about the whole process when the most sustainable method of arable farming there is gets zero recognition, or encouragement.

If Scotgov don’t want to maintain livestock numbers on arable land, shouldn’t set aside be considered as an option in future environmental schemes? I’m not thinking of bare land set aside as we used to see sometimes in the past – there would be an obligation to sow the land in grass and clover on a rotational basis.

There is little comfort in other areas where an arable farmer might want to improve their carbon footprint. My annual carbon audit showed my biggest impacts – after methane – were fertiliser, electricity and fuel, in that order.

My fertiliser carbon footprint is going to be significantly lower this year as we had good results using liquid digestate from a neighbouring AD plant on grass, combined with a purchase of a 24m boom by the contractor. Soaring fertiliser costs encouraged me to use it on our arable crops too.

It is not without its issues, but I am confident we can grow good crops with it. My carbon footprint might be lower as a result and technically if I wasn’t using pesticides, I could claim to be organic – but the person who grew the rye which produced the digestate will have to replace the nutrients lost, so the net effect on farming’s carbon footprint is presumably zero.

Returning to the SAOS conference, Alison Hester gave a fascinating report from the James Hutton Institute farm, at Glensaugh. Their HydroGlen project is looking to produce hydrogen from solar panels and wind turbines, and the hydrogen could be either burnt for heat, burnt in a combustion engine to power vehicles or used in fuel cells to provide electric power.

Glensaugh has no arable land, so unfortunately scientists are not looking at using the electricity to produce ammonia, which is a much more transportable product than hydrogen. It is also very easy to produce urea from it.

So effectively, although costs are still too high, it is now technically possible for every farm in the land to produce its own electricity, fuel and fertiliser from renewable energy. Yet, as it stands, there is no project looking at this on an arable farm, where the gains would be so much more as arable farms use much more energy and fertiliser.

As Andrew Moir pointed out last week, the infrastructure is poor and planning is a minefield. If I wanted to put in a wind turbine here at home, or a field of solar panels, SSE tell me the earliest I can get a grid connection will be 2032.

Leuchars, in Fife (no longer an airbase), won’t let me put up a wind turbine as I am in the line of sight for their radar – although hundreds of turbines are being built 15 miles offshore, not much further away.

Let’s not forget that 100 years ago, around 20% of all arable land was growing fuel in the form of hay and oats for the 'tractors' of the day, and a field of solar panels produces much more energy than a field of rye for an AD plant.

The technology to produce green energy and green hydrogen is already there, but frustratingly out of reach – we can see all the sweeties through the shop window, but we don’t have a penny for a Percy Pig.

If governments truly want the green revolution in arable farming they profess to want, it is technically achievable, but they are going to have to support it financially. I would start in the productive but high energy demanding arable land and also the Hebrides, where fuel is expensive but wind power abundant and it would have the most impact.

I can’t help thinking that the £17.5m Scotgov gave to Forest and Land Scotland to buy Glen Prosen to plant trees, might have been more productively spent elsewhere!