Changes in inputs, timings, tillage, crop-rotation including choice of crops are some of the important agricultural adaptation strategies to climate change. This research aim is to examine whether cropping rotations as adaptation options to climate change can reduce N₂O emissions. The rationale is that leguminous crops in a rotation fix atmospheric nitrogen and bind it in the soil, increasing fertility and reducing the need for synthetic fertilizers. Better management of nitrogen (N) inputs should act to reduce emissions from the grain growing industry.

Experimental measures of N₂O fluxes were used to parameterize DNDC, a process-based denitification-decomposition model to enable us to evaluate N₂O emissions from several crop rotation scenarios commonly practiced in the northwest NSW slopes and plains dryland grain-growing region. N inputs for cereals and oilseeds are via fertilizers, whereas N₂-fixation provides the N requirements for grain legume crops. Simulation results indicate that substituting a legume crop for a cereal or oilseed crop in a rotation significantly reduces the overall N₂O emissions from that rotation. Emissions of N₂O from dryland cropping soils can be significant when high levels of soil nitrate coincide with high soil-water contents. The reduction in N₂O emissions is proportional to the frequency of legume crops in the crop rotation cycle. The results provide the basis for developing low-N₂O-emission adaption strategy to climate change.