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.
Dr David Whitehead, Manaaki Whenua - Landcare Research (2010-present) Professor Frank Kelliher, AgResearch (2010-2017)
Estimates of annual leaching losses of dissolved organic carbon from pastures on Allophanic Soils grazed by dairy cattle, Waikato, New Zealand
Sparling, G. P., E. J. Chibnall, et al. (2016). "Estimates of annual leaching losses of dissolved organic carbon from pastures on Allophanic Soils grazed by dairy cattle, Waikato, New Zealand." New Zealand Journal of Agricultural Research 59(1): 32-49.
Dissolved organic carbon (DOC) flux on a conventional New Zealand dairy farm was measured for 1 year to assess the contribution from DOC to the total farm C budget. Soil solution was collected using ceramic cups at 60 cm depth. Soil drainage was calculated from a water balance model using rainfall, evaporation and soil water storage data from two eddy covariance systems. Solution was collected approximately every 14 days. The DOC concentration was 5.7±15.6 µg C ml-1 (mean and standard deviation). No significant differences (P<0.05) in DOC concentrations were detected between the four soil types, the two sampling areas, nor date of sampling. The accumulative amount of DOC leached was obtained by combining the soil solution concentrations with the daily estimates of drainage. The mean annual amount of DOC leached was 13?29 kg C ha-1 y-1and the contributed 2?5% to the net farm annual carbon balance.