Recent research has confirmed the potential for soils to store higher levels of carbon, specifically within a grassland scenario.
The organisations involved in the research were the Agri-Food and Biosciences Institute (AFBI) and Queen’s University Belfast (QUB).
The matter was discussed at the recent ARCZero open day, hosted by Thompson and Hugh Harbison. The father-and-son team milk 180 autumn-calving cows at Aghadowey in east Co. Derry.
ARCZero is a farmer-led European Innovation Project co-funded by the European Agricultural Fund for Rural Development (EAFRD) and Northern Ireland’s Department of Agriculture, Environment and Rural Affairs (DAERA).
As part of the ARCZero project, all of the soils on the Harbison farm have been carbon assessed. The same assessment work has been carried out on the other six farms involved with the project.
Soils and carbon
QUB scientist Dr. Paul Williams explained that the organic carbon-to-clay ratio can be used as a valuable indicator of soil health.
And this principle can be adapted to identify soils that have the potential to store higher levels of carbon. Moreover, sites of this nature can be identified at specific locations on every farm.
This was a point that was further expanded upon by ARCZero chairman, Prof. John Gilliland.
He said: “This most recent work is confirming that grassland soils have the potential to store additional carbon on an ongoing basis.
“The current Intergovernmental Panel on Climate Change [IPCC] perspective on the matter would indicate that grassland oils plateau off, in terms of their ability to sequester additional carbon, after 20 years.
“This is patently wrong. The results of the long-term slurry trial work at AFBI Hillsborough provided additional evidence of grassland soils’ ability to actively store carbon for up to 50 years.
“And this work is still ongoing,” he added.
pH value
Gilliland went on to confirm that pH value is a critical factor in determining a soil’s ability to store carbon.
“Where mineral soils are concerned, their ability to actively sequester carbon drops-off significantly if pH values fall much below a value of 6.0,” he explained.
“This is because the microbiome of the soil finds it very hard to remain healthy and active under very acidic conditions.
“Until recently, the principles of soil chemistry held sway when it comes to determining the health and quality of a soil. We now know that such is not the case. Feeding the microbiome is the real driver of soil health and productivity.
“We are fast moving from a world focused on soil chemistry, to one within which soil biology will deliver answers to the questions that we need to ask,” he concluded.
