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Unravelling the impacts of climate change on agriculture becomes increasingly important, as the rates and magnitude of its effects are accelerating. Current estimates of the consequences of climate change on nitrous oxide (N 2 O) emissions remain largely uncertain; there is a need for more consistent and comprehensive assessments of this impact. In this study we explored the implications of two IPCC climate change projections (high and medium emissions scenarios) on N 2 O emissions from South West England grasslands for the time slices of a baseline, the 2020s, the 2050s and the 2080s, employing a process-based model (SPACSYS). The model was initially calibrated and validated using datasets collected from three grassland sites of the region. Statistical analysis showed that simulated results had no significant total error or bias compared to measured values. We found a consistent increase in N 2 O emissions of up to 94% under future climate change scenarios compared to those under the baseline, and warming rather than precipitation variability was the overriding factor controlling the N 2 O rise. Modelling fertilizer forms showed that replacing ammonium-nitrate fertilizers with urea or slurry significantly reduced N 2 O emissions (c. 30%). Our study highlights the urgent necessity to adopt viable N 2 O mitigation measures now in order to avoid higher emissions in the future. [ABSTRACT FROM AUTHOR]

Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification-DeComposition (DNDC), has been modified to describe N2O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N2O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N2O emissions increased as the grazing intensity increased. [Copyright &y& Elsevier]

Abstract: A detailed inventory framework was developed to estimate nitrous oxide (N2O) and methane (CH4) emissions from UK agriculture using the IPCC approach. The inventory framework model was illustrated by combining relevant emission factors with agricultural census data for England, Wales, Scotland and Northern Ireland for the year 2000 to derive country-specific emission estimates which were summed to derive the UK total. The framework enables simple assessment to be made of the impact on national emissions of using different emission factors (EFs) (e.g. site- or local-specific compared with IPCC default factors). The framework was used to calculate the average annual emissions of nitrous oxide (N2O) and methane (CH4) for specific livestock and crops, and amounts lost through volatilisation, leaching and runoff for each country in the UK. The framework provides a simple, realistic and transparent approach to estimating national emissions and can easily be updated. [Copyright &y& Elsevier]

Electric vehicles (EV) are considered an option for reducing the transport sector's environmental impacts. Motivated by environmental concerns, governments are formulating policies for the promotion of EV. However, the EV transition has more than environmental benefits; it also has economic and social impacts that are usually not considered. Understanding the effects of the transition to EV on sustainability has become increasingly important in the appropriate public policies formulation and evaluation. This article presents a system dynamics model representing the Colombian EV market and the relationships between the market dynamics and sustainability. This model is used to understand the synergistic effects between the Colombian-market dynamics and sustainability system. The results show that the synergies between market dynamics and sustainability are important. Neglecting them would result in different behaviours from those exhibited in real life and overestimating performance measures. Therefore, the effects of policies that promote EVs would be inadequate if synergies are not considered. This approach is a first step towards improving the understanding of sustainable transport impacts from a holistic perspective and can formulate more robust policies. • System dynamics model broadens understanding of EV market and sustainability feedbacks • Synergistic and constant growth model of the system are compared • Analysis of extreme market scenarios to capture maximum impacts on sustainability • Synergies assessment between Colombian EV market dynamics and sustainability • Constant growth model fails to represent dynamics between sustainability and market [ABSTRACT FROM AUTHOR]

China accounts for a third of global nitrogen fertilizer consumption. Under an International Panel on Climate Change (IPCC) Tier 2 assessment, emission factors (EFs) are developed for the major crop types using country-specific data. IPCC advises a separate calculation for the direct nitrous oxide (N 2 O) emissions of rice cultivation from that of cropland and the consideration of the water regime used for irrigation. In this paper we combine these requirements in two independent analyses, using different data quality acceptance thresholds, to determine the influential parameters on emissions with which to disaggregate and create N 2 O EFs. Across China, the N 2 O EF for lowland horticulture was slightly higher (between 0.74% and 1.26% of fertilizer applied) than that for upland crops (values ranging between 0.40% and 1.54%), and significantly higher than for rice (values ranging between 0.29% and 0.66% on temporarily drained soils, and between 0.15% and 0.37% on un-drained soils). Higher EFs for rice were associated with longer periods of drained soil and the use of compound fertilizer; lower emissions were associated with the use of urea or acid soils. Higher EFs for upland crops were associated with clay soil, compound fertilizer or maize crops; lower EFs were associated with sandy soil and the use of urea. Variation in emissions for lowland vegetable crops was closely associated with crop type. The two independent analyses in this study produced consistent disaggregated N 2 O EFs for rice and mixed crops, showing that the use of influential cropping parameters can produce robust EFs for China. [ABSTRACT FROM AUTHOR]

Bacteria and fungi have been shown to produce nitrous oxide (N 2 O) during denitrification, but their contribution after nitrate (NO 3 −) application to soil is not clearly established. In a microcosm experiment, the relative contribution of bacteria and fungi to N 2 O and carbon dioxide (CO 2) production by four contrasting soils representing different land uses after KNO 3 addition was studied. The soils were daily wetted to 80% water-filled pore space (WFPS) and kept under greenhouse conditions for 10 days. The fungicide cycloheximide and the bactericide streptomycin were used to determine the possible microbial origin of the N 2 O and CO 2 emissions. Non-target effects of the antibiotics on the emission of N 2 O and CO 2 were evaluated using the inhibitor additivity ratio (IAR). The abundance of the bacterial and fungal communities was estimated by quantitative PCR (qPCR) of the bacterial 16S rRNA gene and the fungal internal transcribed spacer (ITS) region, respectively. The gene copy number of bacterial denitrifiers was calculated after quantification of the nirK , nirS , norB , nosZ I and nosZ II genes. After 10 d, regardless of the soil type, the cumulative N 2 O emission from the soils treated with cycloheximide or streptomycin were similar. In all the four soils, N 2 O fluxes were greater (on average 1.8 ± 0.3 times) in soils amended with the fungicide than with the bactericide during incubation for the first 48–96 h. Greater N 2 O emissions (on average 1.7 ± 0.2 times) were detected in soils where bacteria were inhibited in comparison to those treated with the fungicide from 96 to 240 h. On average, 68.5% of the total CO 2 emitted during the 10-d incubation period was produced in soils treated with the fungicide and 31.5% in those treated with the bactericide. The greater contribution of bacteria to the production of N 2 O than fungi during the first 48–96 h was possibly due to a faster used of nitrate. Variations in the abundance of bacterial 16S rRNA genes, the ITS region, and the nirK , nirS , norB and nosZ I bacterial denitrification genes indicated that the antibiotics used to prevent the growth of bacteria and fungi were effective during incubation. These results suggest that both bacteria and fungi should be considered when designing and applying greenhouse gas mitigation strategies in soils and that their relative contribution to produce N 2 O and CO 2 can vary with time and nitrate availability. • In a 10-d microcosm experiment, bacteria dominated fungi for N 2 O emissions during the first 3 d after N-fertilisation. • Fungi dominated bacteria for N 2 O emissions during the remaining 7-d of treatment. • After 10-d, bacteria and fungi similarly contributed to N 2 O production in the four soils analysed. • Bacteria were greater CO 2 producers than fungi after the 10-d treatment in the four soils analysed. • Bacteria and fungi should be considered when designing greenhouse gas mitigation strategies. [ABSTRACT FROM AUTHOR]

Nitrogen (N) stabilizers such as urease inhibitors (UI) and nitrification inhibitors (NI) are promising tools to mitigate N losses from fertilized soils. To better understand the efficacy of UI and NI, a 2-year field trial was carried out in the North China Plain (NCP) to analyze the impact of UI and NI on NH 3 loss and N transformations following urea fertilizer application. Additionally, a laboratory study using an automated continuous-flow incubation system was conducted under controlled conditions, using the same soil, to evaluate the mitigation potential of the N stabilizers on NO, N 2 O and CO 2 emission. The results showed that a novel UI product, Limus® (BASF, Germany), containing active ingredients N-(n-butyl) thiophosphoric triamide (NBPT) and N-(n-propyl) thiophosphoric triamide (NPPT), limited ammonium formation rate and reduced NH 3 loss in both maize (by 85 and 96% for year 1 and 2, respectively) and wheat (by 41 and 64%, for year 1 and 2, respectively) seasons. The 3, 4-dimethypyrazole phosphate (DMPP) amendment significantly retarded nitrate formation rate but the effectiveness was compromised by high ambient temperature; additionally, the NI amendment increased NH 3 emission (by 16 and 24% for maize and wheat year 2, respectively). In the laboratory incubation experiment, addition of the UI reduced emissions of NO, N 2 O and CO 2 by 89, 73 and 19%, respectively, while the addition of the NI reduced the respective emissions by 95, 83 and 24% over the 16 d incubation period. These results suggest that N stabilizers can play a significant role in the mitigation of the environmental impacts of intensive agriculture, and, in particular, that the UI amendment may have the better potential to reduce N losses in the climatic and soil conditions of the NCP, and that the NI should be avoided under high ambient temperatures. Image 1 • Urease inhibitor amendment of urea reduced NH 3 , NO and N 2 O emissions. • Nitrification inhibitor amendment of urea reduced NO and N 2 O but increased NH 3 emissions. • Efficacy of the nitrification inhibitor was compromised by high ambient temperature. • Urease and nitrification inhibitor amendment of urea reduced CO 2 emissions. [ABSTRACT FROM AUTHOR]