Nitrous Oxide Emissions from Perennial Grass Cropping Systems on a Boreal Mineral Soil

Agriculture is the main anthropogenic source of nitrous oxide (N2O). Cultivation of perennial crops is a potential way to reduce N2O emissions. We quantified multi-year N2O emissions from two perennial cropping systems, reed canary grass (RCG) and a mixture of timothy and meadow fescue (TIM), on a boreal mineral soil. Mean annual emissions from TIM and RCG were rather similar, 600 mg N2O m(-2) yr(-1) and 670 mg N2O m(-2) yr(-1), respectively. Compared to the median N2O emissions from cropping systems in mineral soils in northern Europe (230 mg N2O m(-2) yr(-1)), those in this study (720 mg N2O m(-2) yr(-1)) were higher. The higher annual emissions and the observed decrease in annual emissions in our study with time was likely associated with the use of organic fertilizer during the pre-trial period.