Nitrous oxide emissions from European agriculture – an analysis of variability and drivers of emissions from field experiments

Abstract

Abstract. Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot-based experiments. Arable experiments were conducted at Beano in Italy, El Encin in Spain, Foulum in Denmark, Logården in Sweden, Maulde in Belgium, Paulinenaue in Germany, and Tulloch in the UK. Grassland experiments were conducted at Crichton, Nafferton and Peaknaze in the UK, Gödöllö in Hungary, Rzecin in Poland, Zarnekow in Germany and Theix in France. Nitrous oxide emissions were measured at each site over a period of at least two years using static chambers. Emissions varied widely between sites and as a result of manipulation treatments. Average site emissions (throughout the study period) varied between 0.04 and 21.21 kg N2O-N ha−1 yr−1, with the largest fluxes and variability associated with the grassland sites. Total nitrogen addition was found to be the single most important determinant of emissions, accounting for 15% of the variance (using linear regression) in the data from the arable sites (p < 0.0001), and 77% in the grassland sites. The annual emissions from arable sites were significantly greater than those that would be predicted by IPCC default emission factors. Variability of N2O emissions within sites that occurred as a result of manipulation treatments was greater than that resulting from site-to-site and year-to-year variation, highlighting the importance of management interventions in contributing to greenhouse gas mitigation.

Policies for agricultural nitrogen management—trends, challenges and prospects for improved efficiency in Denmark

“…The reduction in fertilizer use and in losses of N therefore contributed to the reduction in estimated N 2 O emissions. It should be noted that the emission factors applied generally is slightly higher than found in experimental studies in Denmark (Chirinda et al 2010, Rees et al 2013.…”

Forest streams are important sources for nitrous oxide emissions

“…During leaching and transport in ground-and surface waters, transformation processes (e.g., denitrification) result in the production of N 2 O, which is water-soluble (Baggs & Philippot, 2011;Wrage et al, 2001). Hence, drainage networks (i.e., ditches and streams) are hotspots for N 2 O emissions (Reay et al, 2012;Rees et al, 2013). Studies on streams in the United States, France and Sweden have demonstrated that, although streams constitute only a small fraction of the total area in the landscape (~0.1%), they can have a disproportionately large impact on total N 2 O emissions from agriculture (3%-6%; Audet, Wallin, Kyllmar, Andersson, & Bishop, 2017;Beaulieu, Arango, Hamilton, & Tank, 2008;Grossel et al, 2016).…”

A Comparative Nitrogen Balance and Productivity Analysis of Legume and Non-legume Supported Cropping Systems: The Potential Role of Biological Nitrogen Fixation

“…Greenhouse gas emissions, for example, depend on the complex interaction of several different biotic and abiotic variables (Snyder et al, 2014). While legume supported crop systems may limit N and C losses (Drinkwater et al, 1998, maize-soybean), management per se is a major factor in achieving this (Rees et al, 2013), especially the use of cover crops, both legume and non-legume grown to accumulate N in the soil for potential incorporation by later crops and to reduce GHG emissions (Thorup-Kristensen et al, 2003; Li et al, 2015). …”