Manioc : Portail | resultats 1 - 12 pour la recherche: Viard, Amélie

La Martinique au premier siècle de la colonisation : 1635-1742
Auteur(s) : Lavigne Sainte-Suzanne, Maurice de
Année de publication :

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Soil N2O emissions in French Guiana after the conversion of tropical forest to agriculture with the chop-and-mulch method
Auteur(s) : Petitjean, Caroline Hénault, Catherine Perrin, Anne-Sophie Pontet, Célia Metay, Aurelie Bernoux, Martial Jehanno, Tifenn Viard, Amélie
Auteurs secondaires : Ecologie des forêts de Guyane (ECOFOG) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) - Institut National de la Recherche Agronomique (INRA) - Université des Antilles et de la Guyane (UAG) - AgroParisTech - Université de Guyane (UG) - Centre National de la Recherche Scientifique (CNRS) Centre Technique Interprofessionnel des Oléagineux, des Protéagineux et du Chanvre (CETIOM) Unité de recherche Science du Sol (USS) ; Institut National de la Recherche Agronomique (INRA) Etablissement Public Local d’Enseignement et de Formation Professionnelle Agricole de Matiti (EPLEFPA) Fonctionnement et conduite des systèmes de culture tropicaux et méditerranéens (SYSTEM) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) - Institut National de la Recherche Agronomique (INRA) - Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro) - Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro) Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (Eco&Sols) ; Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro) - Institut National de la Recherche Agronomique (INRA) - Institut de Recherche pour le Développement (IRD) - Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) - Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) (FEDER, n° Présage 30 081), French Guiana Region, CETIOM, CNES, program QUALISOL Fonds Européen PO FEDER (n° Présage 30 078). This study received an “Investissement d’Avenir” grant managed by Agence Nationale de la Recherche (CEBA, ref. ANR-10-LABX-0025).

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : In French Guiana, the population growth will result in an increase in demand for agricultural products and thus, will lead to an increase in the amount of tropical forests converted into cropland or pasture. Impacts of different agricultural systems on greenhouse gas (GHG) fluxes have not been studied in French Guiana. In this context, the fire-free chop-and-mulch method was used to convert a tropical forest site to agriculture. This study focused on soil nitrous oxide (N2O) emissions and we compared four land uses: (1) the undisturbed tropical forest, (2) recently converted grassland and recently converted croplands (fertilized soybean/maize rotation) with either (3) disk tillage or (4) no tillage.N2O measurements were obtained through the chamber technique and conducted over a 1-year period (measurements began 19 months after the forest was cleared). N2O fluxes were related to soil parameters measured at each sampling date: nitrate and ammonium contents, gravimetric water content (GWC) and temperature.Through the entire period, the mean (±standard error) and median N2O fluxes were 3.8 ± 0.5 and 2.7 g N ha−1 day−1, respectively for undisturbed tropical forest and 2.4 ± 0.9 and 0.8 g N ha−1 day−1, respectively for grassland (mowed Brachiaria ruziziensis). For croplands, no significant difference was found for N2O emissions between both agricultural practices. The mean (±standard error) and median N2O fluxes were 8.5 ± 1.2 and 4.0 g N ha−1 day−1, respectively for disk tillage plots and 8.5 ± 1.3 and 3.6 g N ha−1 day−1, respectively for no tillage plots. Nitrogen inputs (due to the application of fertilizer or due to the mineralization of crop residues) led to higher N2O fluxes, resulting in significantly higher mean N2O emissions from croplands compared to the forest, when only considering land use effect on N2O fluxes in a statistical model. The soil nitrate content, GWC and temperature had a significant positive effect on N2O fluxes. Taking into account these soil parameters in another statistical model, N2O emissions from croplands were not higher than the natural N2O emissions from tropical forest soils. Our results suggest that, if more forest will have to be converted in the course of the expected population growth in French Guiana, it could have low impact on the soil N2O fluxes (similar to natural fluxes from forest) with the improving of farming techniques (for example modification of the splitting of N-fertilizer) in the cropping plots.
ISSN: 0167-8809

hal-01204228
https://hal.archives-ouvertes.fr/hal-01204228
DOI : 10.1016/j.agee.2015.04.004
PRODINRA : 307607

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