University research has potential to reduce carbon emissions on 'million-tonne scale'

Geochemistry researcher for the University of Waikato, Dr Terry Isson, is leading the trial. Photo / Dominico Zapata, University of Waikato

Grinding rock and spreading it onto farmland doesn't seem like a viable way to fight carbon emissions, but a new research trial by the Earth-Life Interactions (ELI) research group based at the University of Waikato (Tauranga campus) and Ngāti Pūkenga is exploring a novel approach towards helping New Zealand to capture carbon dioxide.

Lead researcher Dr Terry Isson, together with Louis Schipper (also from the University of Waikato), has partnered with local iwi Ngāti Pūkenga and Ballance Agri-Nutrients to trial the use of finely-ground mafic rock on Bay of Plenty and Waikato farmland for carbon capture, which could have global implications.

"It is time for us to radically re-imagine the way we live life on Earth. Achieving the goal of being carbon neutral by 2050 is no easy feat… it's time for us to all be bold and creative," Isson says.

The trial is exploring whether spreading dunite (crushed dolomite rock) on pastures and crops can remove carbon dioxide from the atmosphere. Photo / Dominico Zapata, University of Waikato

"We are trying to speed up a natural Earth process that has been operating for billions of years. Very simply, rock types like dunite and basalt found in New Zealand, when ground up and spread onto soil such as agricultural land, have the power to draw down carbon directly out of the atmosphere.

"The chemical break-up of these minerals changes where the carbon wants to live, moving it from the air into water and eventually rock. This product has similar properties to lime in that it raises the pH of the soil, but has additional benefits like the addition of nutrients and, most importantly, the capture of carbon directly from the atmosphere."

Studies are being conducted on both pasture and crops on iwi-owned and managed farmland.

"Carbon capture research often focuses on point sources of emission, but these are uncommon in Aotearoa New Zealand, and this is the first large-scale attempt at diffused carbon capture directly from the atmosphere. If proven, the process will not only provide a pathway to carbon reduction, but will also provide farmers with a concrete way to offset their carbon footprint," Isson says.

From left: Geochemistry researcher Terry Isson, permaculture design consultant for Ngapeke, Rina Te Rehina Walker, and gardening consultant, Olegaro Gaspar. Photo / Dominico Zapata

Rina Te Rehina from Ngāti Pūkenga says the iwi wants to be part of the solution, putting things back into balance (Mauri ora).

"If there is anything at all we can do to help this global climate problem on our land, I don't see why we should not engage," Rina says.

"The world is still in a state of mauri noho (passive existence) and there are not enough of us taking action – it's 'all hui, no do-ee'. Through this proposal, we can achieve mauri oho (an awakening), and if successful, this will take us one step closer to achieving mauri ora (a state of thriving)."

Isson says recent modelling suggests the process has the potential to reduce Aotearoa's carbon emissions on the million-tonne scale, but the idea needs to be rigorously tested in the field.

Permaculture specialist Rina Walker has been collaborating with Terry Isson for a trial on Ngāti Pūkenga land - used for a food forest - in the Bay of Plenty. Photo / Dominico Zapata

"If this technology works, it has the potential to provide farmers and the agriculture industry with a method to actively lower emissions."

The research has received seed funding and feedstock from Ballance Agri-Nutrients, and there are ongoing discussions with the Ministry for Primary Industries (MPI) on the topic. If successful, large-scale rollout of the process could happen within the next decade.