N2O and CH4 emissions from soils under conventional and no-till management practices in Goiânia (Cerrados, Brazil)
Metay, Aurélie | Oliver, Robert | Scopel, Eric | Douzet, Jean-Marie | Aloisio Alves Moreira, José | Maraux, Florent | Feigl, Brigitte, J. | Feller, Christian | Ecole Supérieure d’Agro-Développement International (ISTOM) | Séquestration du carbone et bio-fonctionnement des sols : effets des modes de gestion des agro-écosystèmes tropicaux (SEQBIO) ; Institut de Recherche pour le Développement (IRD [Occitanie]) | Risque environnemental lié au recyclage (UPR RELIER) | Département Performances des systèmes de production et de transformation tropicaux (Cirad-PERSYST) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad) | Fonctionnement et conduite des systèmes de culture tropicaux et méditerranéens (UMR 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)-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM) ; Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Brazilian Agricultural Research Corporation = Empresa Brasileira de Pesquisa Agropecuária (Embrapa) | Systèmes de culture et rizicultures durables (URP SCRID) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Université d'Antananarivo-Centre National de Recherche Appliquée au Développement Rural (FOFIFA)-Consultative Group on International Agricultural Research [CGIAR] (CGIAR)-Africa Rice Center [Côte d'Ivoire] (AfricaRice) ; Consultative Group on International Agricultural Research [CGIAR] (CGIAR) | Gestion de l'Eau, Acteurs, Usages (UMR G-EAU) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-AgroParisTech-Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF)-Institut de Recherche pour le Développement (IRD [Occitanie])-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM) ; Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM) | Département Environnements et Sociétés (Cirad-ES) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad) | Centro de Energia Nuclear na Agricultura (CENA) ; Universidade de São Paulo = University of São Paulo (USP) | This work was completed thanks to the grant given to Aurélie Metay by the French Ministry of Research and Technologies. A financial support was brought by the FFEM (Fonds Français pour l'Environnement Mondial). Project CZZ1224.02X “Bilan comparé des émissions/séquestration des gaz à effet de serre dans les systèmes de culture agro-écologiques (semis direct sous couverture végétale) et les systèmes de culture traditionnels. Le cas du Brésil” and CIRAD (financial support from the CIRAD scientific direction). We also would like to thank the persons that had helped to complete the laboratory analysis at CENA, CIRAD, and CEFE research centers.
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Показать больше [+] Меньше [-]Английский. Nitrous oxide (N 2 O) and methane (CH 4) are important greenhouse gases (GHG) produced respectively by the naturally occurring microbial processes of incomplete denitrification or nitrification and methanogenesis. Tillage practices and climate affect the release of GHGs. No tillage (DMC) systems may increase CO 2-C fixation in soil but also N 2 O and CH 4 emissions. The aim of this article is to question whether the positive effect of a DMC system observed on carbon storage for the topsoil layer in Cerrado soils is offset or not by the N 2 O and/or CH 4 emissions. Two 5-year-old systems, tillage (disc on the first 15 cm called offset: OFF) and a direct-sowing mulch-based crop system (DMC) with an additional cover crop were studied during a cropping cycle. N 2 O and CH 4 fluxes are determined using a closed-chamber, N 2 O and CO 2 concentrations are measured at 3 depths (10-, 20-and 30 cm). No significant difference between treatments was observed for both gases (for emissions and concentrations). Soil N 2 O contents increase from surface to depth (30 cm) and range from 300 ppbv to 3 ppm for both treatments. Total annual estimated emissions of N 2 O range from 31 to 35 g N 2 ON ha − 1 year − 1 for DMC and OFF respectively which is low and corresponds only to 0.03% of the total N-fertilizer applied. Monthly means N 2 O emissions were strongly correlated to monthly means of N 2 O content at 10 cm depth (R 2 = 0.66) and seem to increase exponentially with monthly mean Water Filled Pore Space WFPS (0-10 cm layer) (R 2 = 0.33). CH 4 fluxes were very low as well: both treatment act as source of CH 4 (245 and 403 g CH 4-C ha − 1 year − 1 for DMC and OFF respectively. On a CO 2-C equivalent basis these results correspond to 4.1 and 4.7 kg CO 2-C ha − 1 year − 1 for N 2 O and to 1.9 and 3.1 kg CO 2-C ha − 1 year − 1 for CH 4 for DMC and OFF respectively. As a result, the carbon sequestration balance taking into account the CO 2 , CH 4 and N 2 O on a CO 2-C equivalent basis is in favour of DMC treatment considering that this treatment increases carbon storage originated from CO 2-C for the topsoil (0-10 cm) layer (350 kg C ha − 1 year − 1) in comparison with OFF treatment.
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