Accounting for the utilization of a N₂O mitigation tool in the IPCC inventory methodology for agricultural soils

Abstract

In this study we review recent studies where dicyandiamide was used as a nitrification inhibitor to reduce both N₂O emissions from urine patches and nitrate leaching from pasture systems, and which led to the development of a commercial product for use on farmland. On average, emissions of N₂O and nitrate leaching were reduced by 72% and 61%, respectively. This study then demonstrates how a mitigation tool can be accounted for in the Intergovernmental Panel on Climate Change's inventory methodology when constructing an inventory of New Zealand's agricultural soil N₂O emissions. The current New Zealand specific emission factors for EF1 (0.01), EF3PRP (0.01) and FracLEACH (0.07) are amended to values of 0.0058, 0.0058 and 0.0455. Examples are also given, based on OVERSEER TM models, of the implications of farm management scenarios on N₂O inventories and total greenhouse gas production when using a N₂O mitigation tool; CO₂ equivalents kg⁻¹ milk solid decreased from 14.2 to as little as 11.7, depending on the management scenario modelled.