Keeping our soil healthy and productive


“… more carbon in New Zealand dairy systems will have multiple benefits...”

Professor Louis Schipper

Why have soil carbon levels declined in some soils over the past 30 years and can the trend be reversed?

Carbon makes up about 50% of soil organic matter and is critical not only for soil health but is a key factor in managing global climate change because the transfer of carbon dioxide through photosynthesis can decrease carbon dioxide in the atmosphere.

Professor Louis Schipper, Dr David Campbell and postdoctoral researcher Susanna Rutledge from the University of Waikato's Environmental Research Institute are part of a major research project to investigate whether carbon levels in soils can be increased.

"Carbon content in some soils appears to be below maximum capacity and our research is focused on whether that trend can be reversed and soil carbon levels brought back to their original levels or beyond," Professor Schipper says. 

With funding from the New Zealand Agricultural Greenhouse Gas Research Centre and working in collaboration with Crown Research Institutes Landcare Research, AgResearch and DairyNZ, the team is measuring carbon exchange at adjacent pasture areas at a dairy farm near Waharoa. 

Comparing results between pasture with a traditional ryegrass and clover mix with a more diverse range of pasture species including ryegrass, clover, chicory, plantain, prairie grass and others, the aim is to see if more diverse pasture species increases carbon soil inputs. 

"Farm management practices may hold the key but it's not a simple challenge," Professor Schipper says. "But more carbon in New Zealand dairy systems will have multiple benefits, including decreasing carbon dioxide concentrations in the atmosphere, improving soil structure, nutrient and water retention and providing food for the microorganisms that keep soil healthy."