Simulation of soil nitrogen, nitrous oxide emissions and mitigation scenarios at 3 European cropland sites using the ECOSSE model

Abstract

The global warming potential of nitrous oxide (N 2 O) and its long atmospheric lifetime mean its presence in the atmosphere is of major concern, and that methods are required to measure and reduce emissions. Large spatial and temporal variations means, however, that simple extrapolation of measured data is inappropriate, and that other methods of quantification are required. Although process-based models have been developed to simulate these emissions, they often require a large amount of input data that is not available at a regional scale, making regional and global emission estimates difficult to achieve. The spatial extent of organic soils means that quantification of emissions from these soil types is also required, but will not be achievable using a process-based model that has not been developed to simulate soil water contents above field capacity or organic soils. The ECOSSE model was developed to overcome these limitations, and with a requirement for only input data that is readily available at a regional scale, it can be used to quantify regional emissions and directly inform land-use change decisions. ECOSSE includes the major processes of nitrogen (N) turnover, with material being exchanged between pools of SOM at rates modified by temperature, soil moisture, soil pH and crop cover. Evaluation of its performance at sitescale is presented to demonstrate its ability to adequately simulate soil N contents and N 2 O emissions from cropland soils in Europe. Mitigation scenarios and sensitivity analyses are also presented to demonstrate how ECOSSE can be used to estimate the impact of future climate and land-use change on N 2 O emissions. C max A constant (set at 50 kg N ha -1 ) that adjusts the maximum rate of nitrification possible [this occurs at high levels of NH 4 ? and will be dependent on soil composition (Parton et al. 1996)] D p Potential denitrification rate (kg N ha -1 layer -1 day -1 ) k nitrif A rate constant for nitrification [set at 0.6 (Bradbury et al. (1993)] m b Biological activity rate modifier m NO 3 Modifies the amount of denitrification depending on soil NO 3 -content m pH A rate modifier due to soil pH m t A rate modifier due to soil temperature m w Soil water rate modifier for decomposition m w0 Soil water rate modifier for decomposition at permanent wilting point and saturation = 0.2 m 0 w Soil water rate modifier for denitrification N d The amount of N emitted from the soil during denitrification (kg N ha -1 layer -1 ) N d;N 2The amount of N 2 gas lost by denitrification (kg N ha -1 day -1 ) N d;N 2 O The amount of N 2 O gas lost by denitrification (kg N ha -1 day -1 ) N d50The soil nitrate content at which denitrification is 50% of its full potential (kg N ha -1 layer -1 ) N FERT N in NH 4 ? and urea in the added fertiliser (kg N ha -1 ) N n Nitrification rate (kg N ha -1 layer -1 ) N n;N 2 O The amount of N 2 O gas released during nitrification (kg N ha -1 day -1 ) N NH 4

Exchange of the Greenhouse Gases Methane and Nitrous Oxide Between the Atmosphere and a Temperate Peatland in Central Europe

“…Le Mer and Roger 2001;Lai 2009;Drewer et al 2010;Bell et al 2012;Rees et al 2013). At our site, the single parameter with the highest explanatory power for the observed N 2 O and CH 4 fluxes was air temperature although it was not significant for N 2 O fluxes.…”

Estimating the effect of nitrogen fertilizer on the greenhouse gas balance of soils in Wales under current and future climate

“…ECOSSE can be used to carry out site-specific simulations with detailed input data (e.g. Bell et al 2012;Dondini et al 2015), or spatial simulations using the limited data typically available at larger scales (e.g. Smith et al 2010b).…”

“…The calculated total annual net GHG fluxes from the three investigated land uses across Wales are estimated at an equivalent GWP of 0.34 Mt CO 2 e y -1 . ECOSSE was previously validated and tested for Europe (Bell et al 2012) and Ireland (Khalil et al 2013) and showed its credibility to predict GHG emissions. The model responded appropriately to changes in air temperature, timing of precipitation events, land use and system management, which have strong impacts on GHG and SOC fluxes.…”

“…In the UK, agriculture represents the second largest source of GHG emissions accounting for 9 % of the UK's total emissions (Defra 2013) and emits 79 % of the total anthropogenic emission of nitrous oxide (N 2 O) (Thomas et al 2011). This is due to field management practices such as application of synthetic N fertilizer (Bouwman et al 2002), crop type and cover crop (Bell et al 2012;Abdalla et al 2014) and manure management and grazing (Forster et al 2007) which influence nutrient inputs and hydrological and physical conditions of the soil. Forests and woodlands compose a great stock of C in trees, vegetation and in soils by removing a substantial amount of C from the atmosphere.…”

Direct N2O emission from agricultural soils in Poland between 1960 and 2009

“…Accordingly, larger N 2 O concentrations in the atmosphere are a threat to the climate system since N 2 O is further responsible for the depletion of the ozone layer in the stratosphere (Crutzen 1970;Crutzen et al 2007;Ravishankara et al 2009). Therefore, the reduction in N 2 O emissions has become an essential need (Bell et al 2011). The main sources of N 2 O emissions are terrestrial soils and the oceans (Denman et al 2007;EPA 2010).…”