Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Language: French
    In: Biogeochemistry 2-3 , 395-408., 2015
    Description: Nitrous oxide (N2O) fluxes can increase significantly following small increases in soil water-filled pore space (WFPS). Thus, it is essential to improve our knowledge of this crucial relationship to better model N2O emissions by soils. We studied how much the addition of a gas transport and a gas–liquid equilibrium module to the model of N2O emissions NOE could improve simulation results. A sensitivity analysis of the modified model (NOEGTE: gas transport and equilibrium) was first performed, and then the model was tested with published data of a wetting–drying experiment. Simulated N2O fluxes plotted against WFPS appeared to be bell-shaped during the 7 days simulated, combining the effects of the low N2O production for WFPS 0.95. The WFPS generating the maximum simulated N2O fluxes shifted with time, from 0.76 after 12 h, to 0.79 after 168 h, because of an increase over time of the gas concentration gradient between the soil surface and the atmosphere. NOEGTE appeared able to capture the pattern of N2O emissions monitored in the experimental data. In particular, N2O peaks during drying were well reproduced in terms of timing, but their magnitudes were often overestimated. They were attributed to the increasing gas diffusivity and N2O exchanges from the liquid phase to the gaseous phase.
    Keywords: Modélisation ; Nitrous Oxide Emission Modeling;Water-Filled Pore Space;Gas Diffusivity;Soil ; Indice D'Eau ; Espace Poral ; Sciences De La Terre ; Earth Sciences ; Flux D'Azote ; Émission D'Azote ; Transport De L'Azote ; Protoxyde D'Azote ; Porosité Saturée En Eau
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: French
    In: Biogeochemistry 2-3 , 395-408., 2015
    Description: Nitrous oxide (N2O) fluxes can increase significantly following small increases in soil water-filled pore space (WFPS). Thus, it is essential to improve our knowledge of this crucial relationship to better model N2O emissions by soils. We studied how much the addition of a gas transport and a gas–liquid equilibrium module to the model of N2O emissions NOE could improve simulation results. A sensitivity analysis of the modified model (NOEGTE: gas transport and equilibrium) was first performed, and then the model was tested with published data of a wetting–drying experiment. Simulated N2O fluxes plotted against WFPS appeared to be bell-shaped during the 7 days simulated, combining the effects of the low N2O production for WFPS 0.95. The WFPS generating the maximum simulated N2O fluxes shifted with time, from 0.76 after 12 h, to 0.79 after 168 h, because of an increase over time of the gas concentration gradient between the soil surface and the atmosphere. NOEGTE appeared able to capture the pattern of N2O emissions monitored in the experimental data. In particular, N2O peaks during drying were well reproduced in terms of timing, but their magnitudes were often overestimated. They were attributed to the increasing gas diffusivity and N2O exchanges from the liquid phase to the gaseous phase.
    Keywords: Modélisation ; Nitrous Oxide Emission Modeling;Water-Filled Pore Space;Gas Diffusivity;Soil ; Indice D'Eau ; Espace Poral ; Sciences De La Terre ; Earth Sciences ; Flux D'Azote ; Émission D'Azote ; Transport De L'Azote ; Protoxyde D'Azote ; Porosité Saturée En Eau
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Vadose Zone Journal 8 , ., 2015
    Description: Water in soil is known to be a key factor for controlling N2O emissions because N2O is mainly produced by denitrification in anoxic environments. In this study, we proposed a methodology to image the water and soil structure of a soil sample with X-ray computed tomography while controlling the hydric state and monitoring N2O fluxes. We used a multistep outflow system to apply two wetting–drying cycles to an undisturbed soil. The soil core was scanned with coarse-resolution X-ray computed tomography, one time during wetting and several times during drying, to measure quantitative and qualitative indicators of the pore network. Nitrous oxide emissions were higher during the first (C1) than during the second (C2) wetting–drying cycle for both the wetting and the drying phases. Fluxes increased quickly after the beginning of the drying phase to reach a peak after 5 h. Differences in the intensity of N2O emissions between the two cycles were attributed to differences in the water saturation, air-phase connectivity, and relative gas diffusion coefficient, which led to more or less N2O production, consumption, and entrapment in the soil. The speed of the N2O emissions at the beginning of the drying phase depended on the rate of increase of the air-filled pore volume and connectivity, and was especially well described by the estimated relative gas diffusion coefficient. Parameters of the soil structure were not able to explain completely the intensity of N2O emissions during drying; N2O production and consumption factors were also involved.
    Keywords: N2o ; Earth Sciences ; Flux Hydrique ; Structure Du Sol ; Émission De Gaz ; Modélisation ; Eau Du Sol ; Flux De Gaz ; Tomographie Aux Rayons X ; Sciences De La Terre ; Alternance Humectation Dessication ; Protoxyde D'Azote ; Milieux Et Changements Globaux ; État Hydrique
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Vadose Zone Journal 8 , ., 2015
    Description: Water in soil is known to be a key factor for controlling N2O emissions because N2O is mainly produced by denitrification in anoxic environments. In this study, we proposed a methodology to image the water and soil structure of a soil sample with X-ray computed tomography while controlling the hydric state and monitoring N2O fluxes. We used a multistep outflow system to apply two wetting–drying cycles to an undisturbed soil. The soil core was scanned with coarse-resolution X-ray computed tomography, one time during wetting and several times during drying, to measure quantitative and qualitative indicators of the pore network. Nitrous oxide emissions were higher during the first (C1) than during the second (C2) wetting–drying cycle for both the wetting and the drying phases. Fluxes increased quickly after the beginning of the drying phase to reach a peak after 5 h. Differences in the intensity of N2O emissions between the two cycles were attributed to differences in the water saturation, air-phase connectivity, and relative gas diffusion coefficient, which led to more or less N2O production, consumption, and entrapment in the soil. The speed of the N2O emissions at the beginning of the drying phase depended on the rate of increase of the air-filled pore volume and connectivity, and was especially well described by the estimated relative gas diffusion coefficient. Parameters of the soil structure were not able to explain completely the intensity of N2O emissions during drying; N2O production and consumption factors were also involved.
    Keywords: N2o ; Earth Sciences ; Flux Hydrique ; Structure Du Sol ; Émission De Gaz ; Modélisation ; Eau Du Sol ; Flux De Gaz ; Tomographie Aux Rayons X ; Sciences De La Terre ; Alternance Humectation Dessication ; Protoxyde D'Azote ; Milieux Et Changements Globaux ; État Hydrique
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: French
    In: J2M 2014 : Journées de la mesure et de la métrologie. 2014; 13. Journées de la Mesure et de la Métrologie, Stella Plage , FRA, 2014-10-13-2014-10-16, p.33, 2014
    Keywords: Sciences De La Terre ; Désaturation ; Propriété Hydrique Du Sol ; Saturation ; Earth Sciences ; Potentiel Matriciel ; Émission D'Azote ; Sol ; Système Dynamique Hybride ; Protoxyde D'Azote ; Teneur En Eau ; Teneur En Eau;Potentiel Matriciel;Protoxyde D'Azote;Saturation-Desaturation;Sol
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: 2014; Biogeochemical Processes at Air-Soil-Water Interfaces and Environmental Protection ASWEP, Imola, ITA, 2014-06-23-2014-06-26,, 2014
    Description: N2O fluxes can increase largely due to small increase of the soil water-filled pore space (WFPS). In models, the relationship between N2O fluxes and the WFPS is often described as a continuous exponential curve starting at a WFPS of about 0.62. However, some laboratory and field measurements have evidenced that this relationship could rather be described as Gaussian. To improve our knowledge of this crucial curve for N2O flux modeling, we have developed a laboratory experiment where the wetting and drying dynamics of undisturbed soil cylinders were strictly controlled during N2O flux measurements. We observed that N2O flux peaks could occur during the wetting phase, but more surprisingly we also observed brief and intense peaks during the drying phase. We then hypothesized (1) that N2O was produced and entrapped during the wetting phase, and was emitted from gas pockets and soil solution during the drying phase and, (2) that the addition of a gas transport and a gas-liquid equilibrium modules to an empirical biogeochemical model of N2O emissions could allow the description of the brief peaks observed during soil drying. We build such a model. It was first tested with the experimental data. We also studied its sensitivity to the WFPS parameter. We generated 200 realizations of hydric conditions and bulk densities to estimate the soil gas diffusivity. WFPS was set to be constant during the 7 simulated days. Simulated N2O fluxes plotted against WFPS appeared to be bell-shaped whatever the simulation time, combining the effects of the low N2O production for WFPS0.9. The WFPS generating the maximum simulated N2O fluxes shifted with time, from 0.76 after 12 h, to 0.79 after 168 h, because of an increase over time of the gas concentration gradient between the soil surface and the atmosphere. The study highlighted the role of diffusional processes in soil N2O emissions and the importance to take them into account in N2O modeling.
    Keywords: Modélisation ; Indice D'Eau ; Espace Poral ; Sciences De La Terre ; Earth Sciences ; Émission D'Azote ; Flux D'Azote ; Protoxyde D'Azote ; Porosité Saturée En Eau
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: 2014; Biogeochemical Processes at Air-Soil-Water Interfaces and Environmental Protection ASWEP, Imola, ITA, 2014-06-23-2014-06-26,, 2014
    Description: N2O fluxes can increase largely due to small increase of the soil water-filled pore space (WFPS). In models, the relationship between N2O fluxes and the WFPS is often described as a continuous exponential curve starting at a WFPS of about 0.62. However, some laboratory and field measurements have evidenced that this relationship could rather be described as Gaussian. To improve our knowledge of this crucial curve for N2O flux modeling, we have developed a laboratory experiment where the wetting and drying dynamics of undisturbed soil cylinders were strictly controlled during N2O flux measurements. We observed that N2O flux peaks could occur during the wetting phase, but more surprisingly we also observed brief and intense peaks during the drying phase. We then hypothesized (1) that N2O was produced and entrapped during the wetting phase, and was emitted from gas pockets and soil solution during the drying phase and, (2) that the addition of a gas transport and a gas-liquid equilibrium modules to an empirical biogeochemical model of N2O emissions could allow the description of the brief peaks observed during soil drying. We build such a model. It was first tested with the experimental data. We also studied its sensitivity to the WFPS parameter. We generated 200 realizations of hydric conditions and bulk densities to estimate the soil gas diffusivity. WFPS was set to be constant during the 7 simulated days. Simulated N2O fluxes plotted against WFPS appeared to be bell-shaped whatever the simulation time, combining the effects of the low N2O production for WFPS0.9. The WFPS generating the maximum simulated N2O fluxes shifted with time, from 0.76 after 12 h, to 0.79 after 168 h, because of an increase over time of the gas concentration gradient between the soil surface and the atmosphere. The study highlighted the role of diffusional processes in soil N2O emissions and the importance to take them into account in N2O modeling.
    Keywords: Modélisation ; Indice D'Eau ; Espace Poral ; Sciences De La Terre ; Earth Sciences ; Émission D'Azote ; Flux D'Azote ; Protoxyde D'Azote ; Porosité Saturée En Eau
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: French
    In: J2M 2014 : Journées de la mesure et de la métrologie. 2014; 13. Journées de la Mesure et de la Métrologie, Stella Plage , FRA, 2014-10-13-2014-10-16, p.33, 2014
    Keywords: Sciences De La Terre ; Désaturation ; Propriété Hydrique Du Sol ; Saturation ; Earth Sciences ; Potentiel Matriciel ; Émission D'Azote ; Sol ; Système Dynamique Hybride ; Protoxyde D'Azote ; Teneur En Eau ; Teneur En Eau;Potentiel Matriciel;Protoxyde D'Azote;Saturation-Desaturation;Sol
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Proceedings of the Complex Soil Systems Conference “A Path to Improved Understanding of Complex Soil Systems”. 2014; Complex Soil Systems “A Path to Improved Understanding of Complex Soil Systems”, Berkeley, USA, 2014-09-03-2014-09-05, p.51, 2014
    Keywords: Eau Du Sol ; N2o ; Hysteresis ; Sciences De La Terre ; Earth Sciences ; Alternance Humectation Dessication ; Émission D'Azote ; Teneur En Eau ; Protoxyde D'Azote ; Séchage ; Humidification ; État Hydrique ; Mouillage
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: Proceedings of the Complex Soil Systems Conference “A Path to Improved Understanding of Complex Soil Systems”. 2014; Complex Soil Systems “A Path to Improved Understanding of Complex Soil Systems”, Berkeley, USA, 2014-09-03-2014-09-05, p.51, 2014
    Keywords: Eau Du Sol ; N2o ; Hysteresis ; Sciences De La Terre ; Earth Sciences ; Alternance Humectation Dessication ; Émission D'Azote ; Teneur En Eau ; Protoxyde D'Azote ; Séchage ; Humidification ; État Hydrique ; Mouillage
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages