New Zealand's pastures: Carbon sinks or sieves?

Soil matters:  17 percent of our GDP depends on the top 15 centimetres of our soil.

Carbon or organic matter - is critical to maintaining soil quality, and may also help New Zealand meet its international obligations by removing CO2 out of the atmosphere. 

But little is known about the impacts of changing pasture management practices on the amounts of carbon stored in soil.

With colleagues from Landcare Research and GNS Science, University of Waikato Associate Professor Louis Schipper has been measuring soil carbon at more than 120 pastures sites around New Zealand, and comparing their information with data recorded from the same sites around 30 years ago.

This work is funded by the Ministry of Agriculture and Forestry and the Ministry of Science and Innovation, with support from DairyNZ, and is aimed at determining how different land management practices alter long-term stores of soil carbon.

In a related project, Dr Schipper and colleagues Dr Susanna Rutledge and Dr Dave Campbell are leading research at a DairyNZ farm to determine ways to increase soil carbon storage in pasture soils.

The researchers want to see if alternative pasture species – with greater root biomass and inputs of carbon into soils - can increase soil carbon storage. They aim to work with farmers to introduce a more diverse pasture sward into their farming systems.

Funded by the New Zealand Agricultural Greenhouse Gas Research Centre, the project aims to develop a “carbon balance sheet” so that farmers can compare the environmental and production consequences of their land management decisions.