Reducing nitrous oxide flux from animal wastes
Nitrous oxide (N2O) is a greenhouse gas that is generated from biological activity in the soil. N2O production is enhanced when animal effluent is added to the land--a current practice which is actively encouraged in New Zealand.
The influence of a nitrification inhibitor (dicyandiamide--DCD) on the rate of N2O being released from soils receiving effluent was determined in collaborative studies at the Institute of Grassland and Environmental Research in the United Kingdom. Dairy cattle effluents, which were amended with DCD, were applied to a field site in the autumn and in situ samples of gas were taken periodically. Compared with soil receiving unamended effluent, DCD significantly reduced N2O emissions from both dung and urine applications. Although such inhibitors had been reported to reduce N2O emissions from fertilizer-N application, their effect on effluent-N was previously unknown.
Using DCD therefore provides a potential means of limiting both the release of N2O into the atmosphere, and the movement of nitrates through soil into groundwater.
Funding: Funding for this work was provided by the Foundation for Research, Science and Technology and the New Zealand Dairy Research Institute (NZDRI)