Soil carbon restored – Crop Production Magazine
The conclusion of a nationwide survey suggests UK farmers have reversed the trend of failing carbon levels in arable soils, potentially reducing their impact on climate change ...
Sceptics said it was impossible, others that it’d take many years, but against all the apparent odds soil carbon levels look to be increasing and experts suggest positive, on-farm actions are the likely explanation. While there are no laurels to rest upon just yet, the good news is that UK soils appear to be more sustainable and in better shape as a result.
Furthermore, in research published in the European Journal of Soil Science, it suggests that after prolonged, historic decline, soil carbon levels are starting to increase. Looking in more detail, initial analyses since the start of a survey some 40 years ago showed that soil organic carbon (SOC) was being lost at a rate of 0.16t/ha every year. However, during the 15 years to 2022, cropland soils have annually accrued 0.17t/ha of SOC on average – that’s equivalent to 0.74 mega tonnes of carbon across the UK every year.
According to Dr Laura Bentley, the environmental scientist who fronted the work, this data clearly demonstrates that topsoil properties can be restored. “It offers real hope that a concerted effort by land managers can halt, and potentially reverse, SOC loss from cropland soil,” she says.
Hutchinsons’ Dick Neale supports the view that the recent on-farm adoption of soil improvement measures could explain the increase in soil carbon found in the survey.
“The results don’t surprise me in the slightest, but it’s heartening to have data to prove that the positive efforts taken during the past 10-12 years have worked on a national scale.
“Soils and soil improvement is very much at the forefront of our engagement on farm, and have been ever since we launched our healthy soils assessment service back in 2015. One of the first courses any new entrant to our business goes on is soils, and we now have an on- going training cycle that updates all our agronomists on management, nutrition and microbiology.”
Dick believes farmers have responded positively and wholeheartedly to the focus on better soil husbandry. “You only have to look at the fact that attendance figures at Groundswell are now 10- fold what they were 12 years ago.
“While you can, see, feel and smell the improvements in soil condition during the past decade, the problem has been to quantify these changes. This Countryside Survey goes some way towards doing that.”
And like Laura, he believes that no single management change is responsible, rather a mix of techniques. “Incorporating straw, reducing ploughing and mixing up cultivations have all made a significant impact, but anything that adds organic matter or boosts natural soil recovery processes will play a part.
“Other improvements have come from forced changes where we’ve had to use stale seedbeds and shallow tillage to halt blackgrass, and the use of cover crops has meant less carbon is burned-off and more is introduced to the system,” he comments.
According to Dick, while no-one wants to ban the plough as there are times when it’s required, systems should never go back to deep inversion wholesale. “I’d advise continuing to add carbon to the soil, sometimes removing but other times leaving straw, and using digestate and other materials appropriately.
“You can visibly see the benefits on farm over time and data such as this confirms trends have been reversed and that we’re bringing soil back to life.”
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