Increasing the quantity of carbon stored in agricultural soils has the potential to offset emissions of greenhouse gases to the atmosphere, while soil carbon losses would further add to those emissions.
However, realising this mitigation potential is technically challenging when soil carbon stocks are already high (as they are in New Zealand), potential changes in soil carbon are small and spatial variability is high.
The current NZAGRC programme has three distinct components:
(1) testing specific management practices that may increase the long term soil carbon store in field situations;
(2) developing and using models to predict how a range of management practices may influence long and short tem soil carbon storage; and
(3) identifying those factors that influence the stability of current or newly added soil carbon.
We have also supported international work to map on farm soil carbon and will participate in the international research programme CIRCASA.
Dr David Whitehead, Manaaki Whenua - Landcare Research (2010-present)
Professor Frank Kelliher, AgResearch (2010-2017)
1550 Keith Goulding (Rothamsted Research, UK)
Keith provided an international perspective on nitrous oxide and soil carbon research. With respect to N2O, he highlighted work on investigating the genes related to nitrous oxide emissions and noted that there is one clear message for reducing nitrous oxide, avoid excess nitrogen.
The IPCC has recently indicated that biochar may have a part to play in reducing agricultural GHGs and a number of research groups are searching for natural nitrification inhibitors.
Keith indicated that soil carbon needs to be considered carefully. Data were published that could be interpreted to imply that grasslands could continue to sequester carbon indefinitely. However, this has been refuted and there is agreement that for a specific system there is an upper limit for carbon, and he noted the interesting work in New Zealand in this area. t been proven yet, but it appears that the deeper roots also reduce run off significantly and thus could offer multiple benefits.
Keith concluded with a warning that too much emphasis on soil carbon sequestration could risk taking our eyes off more important climate change threats, such as land clearance and wetland drainage. He also stressed that our priorities should be promotion of good land stewardship and integrated solutions that consider the whole system and do not merely “pollution swap”.
- 12_Goulding_1550_International perspectives.pdf (5.37MB)
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