Modeling soil respiration in wheat fields
; ; et al
Poster (2013, April 09)Detailed reference viewed: 4 (0 ULg)
Soil respiration partitioning and its components in the total agro-ecosystem respiration
; ; et al
Poster (2013, April 09)
Annual-scale adaptation of a soil heterotrophic respiration model to three agricultural sites in Belgium and South-Western France.
Buysse, Pauline ; ; et al
in Geophysical Research Abstracts (2010, May 06), 12Detailed reference viewed: 19 (7 ULg)
Modelling total soil respiration in agricultural soils.
Buysse, Pauline ; ; Carnol, Monique et al
Poster (2010, January 12)
Soil respiration is a process which results in CO2 release from the soil to the atmosphere. It comprises two main components. The first one is heterotrophic respiration: CO2 is produced by soil ... [more ▼]
Soil respiration is a process which results in CO2 release from the soil to the atmosphere. It comprises two main components. The first one is heterotrophic respiration: CO2 is produced by soil microorganisms while decomposing the substrate. The second one is autotrophic respiration in which CO2 originates from roots and rhizospheric organisms. All the CO2 is then transported to the surface by diffusion (see Goffin et al., this session). Many biotic and abiotic factors play a role in soil respiration, making this process complex to analyze and understand. Temperature often appears as the most important driving variable. Besides that, interest in the future CO2 emissions from agricultural soils has been growing. Indeed, these ecosystems are a major concern from environmental, economic and social points of view. In particular, the choice of cultural practices and residue management techniques has a strong influence on CO2 emissions from agricultural systems. This work aims at getting to a better understanding of soil respiration in agricultural soils. To reach this goal, many semi-mechanistic models have been previously developed at very different spatio-temporal scales. We intend to adapt such an existing model to crop soils, within a spatial scale of a cultivated field and an annual temporal scale. The model will be validated by using flux measurements carried out at three different crop sites situated in the Hesbaye region in Belgium (Lonzée) and in the South West of France (Lamasquère, Auradé). The study was focused first on soil heterotrophic respiration. Within this part, short term sensitivity of this component to temperature was studied by means of a laboratory incubation experiment. This one was performed with soil samples taken at the Lonzée site. Among the many interesting results we got, it showed a clear sensitivity of soil heterotrophic respiration to short term temperature changes. In parallel, the soil heterotrophic model was calibrated on soil chamber measurements taken at the Lonzée site (Belgium). Next steps in this part of the work will be to calibrate the model using the data from the French sites, and finally to validate the model on the three sites. Afterwards, an autotrophic respiration submodel will be implemented and the results compared to field measurements carried out at the three sites. A further development could consist in simulating agricultural practices to take their impacts on CO2 emissions from crops into account. [less ▲]Detailed reference viewed: 47 (7 ULg)
Parameterization and initialization of a soil organic matter decomposition model in an agricultural soil.
Buysse, Pauline ; ; et al
Poster (2009, September)
Organic matter decomposition and associated heterotrophic respiration fluxes are widely studied, as these processes could be modified under global warming. Many models have been built at different ... [more ▼]
Organic matter decomposition and associated heterotrophic respiration fluxes are widely studied, as these processes could be modified under global warming. Many models have been built at different temporal and spatial scales to contribute to a better understanding of the mechanisms involved and to quantify soil carbon fluxes. Yet, agroecosystems have been less investigated so far, despite their considerable importance. In this study, a daily-time step ecosystem model derived from CENTURY is described, parameterized and initialized for the Carboeurope agricultural site of Lonzée in Belgium. At this stage, the model aims at describing soil heterotrophic respiration and carbon dynamics in the soil. Model parameterization was performed on the basis of a literature survey (biochemical parameters) and of data collected at the site itself (soil carbon content and soil texture). In order to set up the carbon repartition between the different pools of the model, an initialization phase was run until equilibrium was reached. For this phase, mean daily climatic data were used and the soil was cultivated with winter wheat, considering that all residues were brought to the soil at harvest. At the end, the repartition was found to be independent from the simulated soil carbon content. Simulations showed a very high sensitivity of the model to the amount of incorporated residues and allowed an estimation of the amount of residues that lead the soil to a stable state. It was compatible with field observations. The model was then run with 2007 climatic data and the above-mentioned carbon repartition to simulate heterotrophic respiration. A comparison between these simulated fluxes and automatic measurements of soil respiration, performed during a 3-month period in spring 2007 on a bare zone of the field, showed a reasonable good agreement. Most of the discrepancies between measured and simulated fluxes corresponded to dry events, attesting of a need to reconsider the relationship between soil heterotrophic respiration and soil moisture in the model. To go further with the assessment of the model reliability, a calibration on data from the French Carboeurope site of Lamasquère will be achieved. Other sites may also be used. This heterotrophic soil respiration model is intended to be part of a more complete soil respiration model focused on agroecosystems and developed at the annual and ecosystem scales. In the end, autotrophic respiration, nitrogen mineralization and crop management would also be included. [less ▲]Detailed reference viewed: 45 (2 ULg)
Modelling soil heterotrophic respiration in an agricultural soil: Model structure and first comparison with experimental data.
Buysse, Pauline ; ; et al
Poster (2008, November 17)
Ce travail visait à adapter un modèle de respiration hétérotrophe du sol à un site agricole situé en Hesbaye (Belgique) et cultivé avec une rotation betterave sucrière / blé d’hiver / pomme de terre / blé ... [more ▼]
Ce travail visait à adapter un modèle de respiration hétérotrophe du sol à un site agricole situé en Hesbaye (Belgique) et cultivé avec une rotation betterave sucrière / blé d’hiver / pomme de terre / blé d’hiver. A long terme, ce modèle fera partie intégrante d’un modèle plus important qui décrira la respiration totale du sol et l’évolution du contenu en carbone du sol dans les cultures. Le modèle utilisé dans ce travail est dérivé du modèle Century, possède un pas de temps journalier et couvre une échelle spatiale de l’ordre de l’écosystème. La paramétrisation du modèle a été réalisée sur base d’une recherche bibliographique et de données collectées sur le site Carbo-Europe de Lonzée. Les caractéristiques du sol sont issues d’analyses réalisées sur des sols limoneux, typiques de la région de Hesbaye. Les variables conductrices (variables météorologiques et apports de litière) furent obtenues suite à une campagne de mesures de 4 ans réalisée sur le site expérimental de Lonzée. Les paramètres biochimiques du blé, de la pomme de terre et de la betterave furent tirés de la littérature. Une analyse de sensibilité fut réalisée en vue de classer les différents paramètres par rapport à leur impact sur le taux de respiration et les contenus en carbone de chaque pool. Les paramètres les plus importants étaient ceux contrôlant la réponse à la température, l’apport de litière et les teneurs en lignine et en azote. Des différences d’impact à court et long terme ont aussi été mises en évidence, notamment à cause de la dynamique de stabilisation des pools et des types de résidus de culture. Finalement, cette analyse nous a permis de définir de futures expériences qui seraient nécessaires pour améliorer l’ajustement du modèle sur des données expérimentales. [less ▲]Detailed reference viewed: 27 (6 ULg)
Adaptation of a soil heterotrophic respiration model to an agricultural soil.
Buysse, Pauline ; ; et al
Poster (2008, September)
This work aimed at adapting a model of soil heterotrophic respiration to an agricultural soil situated in the Hesbaye region (Belgium) and cultivated with a sugar beet / winter wheat / potato/ winter ... [more ▼]
This work aimed at adapting a model of soil heterotrophic respiration to an agricultural soil situated in the Hesbaye region (Belgium) and cultivated with a sugar beet / winter wheat / potato/ winter wheat rotation. This model would be integrated as a sub routine in a larger model describing soil respiration and soil carbon content evolution in crops and that will include autotrophic respiration and CO2 diffusion in soil. The present model is run at a daily time step and at the ecosystem spatial scale and is derived from the CENTURY model. Model parameterisation was performed on the basis of literature survey and of data collected at the Carboeurope agricultural site of Lonzée. Soil characteristics were determined on the basis of analyses performed on loamy soils, typical of the Hesbaye region. Driving variables (meteorological variables and litter input) were obtained during a 4 year measurement campaign performed at the Lonzée experimental site. Biochemical parameters for wheat, potato and sugar beet crops were collected from literature. However, a large parameter variability was noticed as well as a lack of information concerning sugar beet and potato. A sensitivity analysis was performed in order to classify the different parameters in terms of their impact on the respiration rate and carbon contents of each pool. It showed that the most important parameters were those controlling the temperature response, the litter input and its nitrogen and lignin content. The sensitivity analysis also showed differences in parameter impact between short and long term, notably because of pool stabilisation dynamics and crop residue types. This analysis allowed defining the further experiments that need to be developed in order to improve model adjustment on experimental data. [less ▲]Detailed reference viewed: 19 (4 ULg)
Cross-calibration functions for soil CO2 efflux measurement systems
; ; Perrin, Dominique et al
in Annals of Forest Science : a Multidisciplinary and International Journal (2006), 63(5), 477-484
Different soil CO2 efflux measurement systems and methodologies were used to estimate the annual soil respiration of different forest sites. To allow comparison between these annual values, this study ... [more ▼]
Different soil CO2 efflux measurement systems and methodologies were used to estimate the annual soil respiration of different forest sites. To allow comparison between these annual values, this study aimed to cross-calibrate five soil CO2 efflux (RS) closed dynamic chamber systems, and compare the in situ measurement methodologies. We first assessed the impact of the measurement methodology on RS by studying the effects of three parameters: record duration, time lag before starting to record and the mode of chamber-soil contact (use of collars or insertion of the chambers into the soil). Secondly, we directly compared systems with identical methodology during field measurements on three forest sites. We observed a significant influence of the chamber-soil contact mode (no impact of the record duration and duration before starting to record). Measurements obtained by insertion led to significantly higher estimates of RS than those obtained using collars (up to 28%). Our inter-comparison showed that deviations existing between in situ measurements performed with the different systems were partly systematic and could be corrected using simple linear equations. Measurements of pressure difference between the inside and the outside of soil chambers allowed explaining a part of the observed deviations between systems. Finally, we assessed the influence of the cross-calibration equations on annual respiration of two beech forest soils. [less ▲]Detailed reference viewed: 34 (3 ULg)