29 % N2O emission reduction from a modelled low-greenhouse gas cropping system during 2009-2011

Atmospheric concentration of nitrous oxide (N2O), a greenhouse gas (GHG), is rising largely due to agriculture. At the plot scale, N2O emissions from crops are known to be controlled by local agricultural practices such as fertilisation, tillage and residue management. However, knowledge of greenhouse gas emissions at the scale of the cropping system is scarce, notably because N2O monitoring is time consuming. Strategies to reduce impact of farming on climate should therefore be sought at the cropping system level. Agro-ecosystem models are simple alternative means to estimate N2O emissions. Here, we combined ecosystem modelling and field measurements to assess the effect of agronomic management on N2O emissions. The model was tested with series of daily to monthly N2O emission data. It was then used to evaluate the N2O abatement potential of a low-emission system designed to halve greenhouse gas emissions in comparison with a system with high productivity and environmental performance. We found a 29 % N2O abatement potential for the low-emission system compared with the high-productivity system. Among N2O abatement options, reduction in mineral fertiliser inputs was the most effective

Modeling of nitric oxide emissions from temperate agricultural ecosystems.

48 p.Arable soils are a significant source of nitric oxide (NO), most of which is derived from nitrogen fertilizers. Precise estimates of NO emissions from these soils are thus essential to devise strategies to mitigate the impact of agriculture on tropospheric ozone regulation. This paper presents the implementation of a soil NO emissions submodel within the environmentally-orientated soil crop model, CERES-EGC. The submodel simulates the NO production via nitrification pathway, as modulated by soil environmental drivers. The resulting model was tested with data from 4 field experiments on wheat- and maize-cropped soils representative of two agricultural regions of France, and for three years encompassing various climatic conditions. Overall, the model gave correct predictions of NO emissions, but shortcomings arose from an inadequate vertical distribution of fertilizer N in the soil surface. Inclusion of a 2-cm thick topsoil layer in an 'micro-layer' version of CERES-EGC gave more realistic simulations of NO emissions and of the under-lying microbiological process. From a statistical point, both versions of the model achieved a similar fit to the experimental data, with respectively a MD and a RMSE ranging from 1.8 to 6.2 g N-NO ha−1 d−1, and from 22.8 to 25.2 g N-NO ha−1 d −1 across the 4 experiments. The cumulative NO losses represented 1 to 2% of NH+4 fertilizer applied for the maize crops, and about 1% for the wheat crops. The 'micro-layer' version may be used for spatialized inventories of biogenic NO emissions to point mitigation strategies and to improve air quality prediction in chemistry transport models

Two years monitoring of soil N2O emissions on durum wheat in a Mediterranean area: the effect of tillage intensity and N-fertilizer rate

Two years monitoring of soil N2O emissions on durum wheat in a Mediterranean area: the effect of tillage intensity and N-fertilizer rate. EGU General Assembly 2016 Conference Abstracts, European Geophysical Unio

LIFE+IPNOA mobile prototype for the monitoring of soil N2O emissions from arable crops: First-year results on durum wheat

Agricultural activities are co-responsible for the emission of the most important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Development of methodologies to improve monitoring techniques for N2O are still needful. The LIFE+IPNOA project aims to improve the emissions monitoring of nitrous oxide from agricultural soils and to identify the agricultural practices that can limit N2O production. In order to achieve this objective, both a mobile and a stationary instrument were developed and validated. Several experimental field trials were set up in two different sites investigating the most representative crops of Tuscany (CentralItaly), namely durum wheat, maize, sunflower, tomato and faba bean. The field trials were realized in order to test the effect on N2O emissions of key factors: tillage intensity, nitrogen fertiliser rate and irrigation. The field trial on durum wheat was set up in 2013 to test the effect of tillage intensity (minimum and conventional tillage) and nitrogen fertilisation rate (0, 110, 170 kg N ha–1) on soil N2O flux. Monitoring was carried out using the IPNOA mobile prototype. Preliminary results on N2O emissions for the durum wheat growing season showed that mean daily N2O fluxes ranged from –0.13 to 6.43 mg m–2 day–1 and cumulative N2O-N emissions over the period ranged from 827 to 2340 g N2O-N ha–1. Tillage did not affect N2O flux while increasing nitrogen fertilisation rate resulted to significantly increase N2O emissions. The IPNOA mobile prototype performed well during this first year of monitoring, allowing to catch both very low fluxes and peaks on N2O emissions after nitrogen supply, showing a good suitability to the field conditions

Multi-ancestry sleep-by-SNP interaction analysis in 126,926 individuals reveals lipid loci stratified by sleep duration.

Both short and long sleep are associated with an adverse lipid profile, likely through different biological pathways. To elucidate the biology of sleep-associated adverse lipid profile, we conduct multi-ancestry genome-wide sleep-SNP interaction analyses on three lipid traits (HDL-c, LDL-c and triglycerides). In the total study sample (discovery + replication) of 126,926 individuals from 5 different ancestry groups, when considering either long or short total sleep time interactions in joint analyses, we identify 49 previously unreported lipid loci, and 10 additional previously unreported lipid loci in a restricted sample of European-ancestry cohorts. In addition, we identify new gene-sleep interactions for known lipid loci such as LPL and PCSK9. The previously unreported lipid loci have a modest explained variance in lipid levels: most notable, gene-short-sleep interactions explain 4.25% of the variance in triglyceride level. Collectively, these findings contribute to our understanding of the biological mechanisms involved in sleep-associated adverse lipid profiles

La mesure des flux turbulents

National audienc

Influence of Origin and Post-treatment on Greenhouse Gas Emissions After Anaerobic Digestate Application to Soil

Anaerobic digestion is a beneficial organic waste management technology that, in addition to biogasused for energy production, produces a by-product called anaerobic digestate, which can be used as a fertilizer or as an amendment as long as it has no harmful effects on the environment. The objective of the research described in this article was to assess one of these possible harmful effects, associated with the release of greenhouse gas emissions (GHG). Four anaerobic digestates were subjected to phase separation, and some of them also to composting, drying or reverse osmosis. Carbon dioxide (CO2) and nitrous oxide (N2O) emissions were measured during incubations of soil-digestate mixtures under controlled conditions. The mineralization of organic carbon reached 28–58 % of digestate organic carbon after 3 months in the presence of the solid digestates, and was lower (18–42 %) for the liquid digestates. The raw digestates had intermediate intensity of organic carbon mineralization to CO2. Drying and composting reduced CO2 emissions by stabilizing the digestate organic matter. N2O emission factors varied between 0.11 and 2.10 % of total digestate N depending on the origin and state of the digestates (raw, solid, liquid, composted). The highest emissions were measured with the raw digestates, and the lowest generally with the liquid ones. The study showed that in addition to phase separation, composting also reduced GHG emissions whereas drying and reverse osmosis considerably increased these emissions. Compostedand dried digestates can be used as organic amendment leading to potential carbon storage larger than GHG emission, while for raw digestates, the GHG emissions always exceeded potential C storage