Soil is a farmer’s greatest asset, with a single teaspoon containing more living organisms than there are people living on earth. Yet what actually constitutes healthy soil is still to be fully understood.
Phil Jarvis, a farm manager and member of the NFU Environment Forum, explains ‘soil is complicated’.
He says: “The interactions between physical, chemical and biology within the soil are well-researched, but more difficult to be completely understood.”
As we are understanding its importance, we are also asking our soils to provide not just food, but also biodiversity, flood protection and carbon storage.
Following stark warnings about soil erosion, Defra Secretary of State Michael Gove has warned the UK is 30-40 years away from the ‘fundamental eradication of soil fertility’.
In response, Mr Gove has committed to including targets for soil health in the Agriculture Bill, which will set in stone the UK’s new farm policy after it leaves the European Union and its Common Agricultural Policy.
A new farm policy, focused on paying farmers for delivering public goods, could incentivise farmers to improve soil management, says Mr Gove, for example, by using crop rotation.
Payments to farmers could also be linked to enhancing water quality, enabling carbon storage and mitigating against flooding. UK soils, for example, store an estimated 130 trillion litres of water, far more than is contained in all the UK’s lakes and rivers combined.
Independent ecologist and agronomist Marek Nowakowski, who advises a range of organisations including Defra and Natural England, says: “We have been robbing the soils and now it is time to pay them back.
“In the future, farmers will be paid for public goods. More stable soils, less soil erosion and carbon capture will be some of those goods.”
How Defra will actually measure soil health and quality is still unclear, but soil researchers say there are accepted principles, such as building organic matter and growing a diverse varied rotation.
Mr Nowakowski says: “The one that is most talked about is raising soil organic matter.”
More than one-third of farmers are already keeping a track of the organic matter content of soil, according to Defra’s most recent farm practices survey.
Mr Nowakowski says: “The higher that content, the more consistent and higher yields farmers are seeing and the less fertility he or she has to then buy out of a bag.”
One institution which has spent decades researching soil health is Rothamsted Research.
Agronomist Dr Stephan Haefele says alongside the ecosystem services healthy soils can provide, such as storing water in times of flooding, soil health has always been related to productivity for both arable and livestock farmers.
He also flags up examples of how soil health can be negatively impacted.
“A lot of farmers sell straw, which is an issue for the soil as it removes organic matter that would otherwise go into the soil.”
But there is a solution to this loss. Jonathan Booth at Ranby Hall, Market Rasen, Lincolnshire, has a muck and straw agreement with a pig unit which he sublets to tenants.
He says: “We supply straw into the unit and we get muck back. I am a big believer that if you take out, you put back in a greater amount.”
Mr Booth started the arrangement seven years ago, with his soils becoming noticeably unworkable, especially in summer, and his yields falling.
He says: “We have tried to rectify this and replenish as much as possible and it has definitely made a huge difference for us. With poor soils, we were up against it.”
While organic matter content was accepted as an important building block of healthy soils, there was, as yet, ‘no grand recipe’ farmers could use to improve soil health on-farm, says Dr Haefele.
Solutions required detailed knowledge of the specific conditions of individual farms, he adds.
However, the NFU says it has noted an increasing interest in, and adoption of, practices designed to protect and enhance soil quality by farmers.
These have included the use of reduced tillage technology, so soil is not overworked and damaged, cover cropping to reduce soil erosion and replenish nutrients essential for crop growth, and the use of low impact machinery to reduce soil compaction, which can improve root growth and make it easier for water to penetrate soil.
David Hanson, an agricultural specialist at NatWest, who works with Mr Booth as his relationship manager, says: “It is important to make that investment, as Jonathan has on his farm, to safeguard productivity and profitability in the long-term.”
Deciding whether that is worthwhile or not is a decision every farmer and land manager has to decide for themselves and their business, says Mr Nowakowski.
He says: “If you believe a healthy soil is a better soil, you should work towards improving it.”
Policy announcements from Mr Gove over the past two years have made it clear that Government policy is moving towards paying farmers for how they manage soil and outcomes linked to that.
Roddy McLean, director of agriculture at NatWest, says: “It is clearly going to become a material issue for the farming industry and one it needs to get its head around to capitalise on in the long-term.”
And paying farmers to improve soil health makes sense, says Dr Haefele.
“Farms have always been interested in soil health, but it just needs an incentive to work well. Often farmers want to maintain their land, but other competitive forces are pushing them in a different direction.”
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