Impact of nutrient additions on free-living nitrogen fixation in litter and soil of two French-Guianese lowland tropical forests

Van Langenhove Leandro, Depaepe Thomas, Verryckt Lore T., Vallicrosa Helena, Fuchslueger Lucia, Lugli Laynara F., Bréchet Laëtitia, Ogaya Romà, LLusià Joan, Urbina Ifigenia, Gargallo‐Garriga Albert, Grau Oriol, Richter Andreas, Peñuelas Josep, Van Der Straeten Dominique, Janssens Ivan A.. 2021. Impact of nutrient additions on free-living nitrogen fixation in litter and soil of two French-Guianese lowland tropical forests. Journal of Geophysical Research: Biogeosciences, 126 (7):e2020JG006023, 15 p.

Quartile : Q1, Sujet : GEOSCIENCES, MULTIDISCIPLINARY / Quartile : Q2, Sujet : ENVIRONMENTAL SCIENCES

Résumé : In tropical forests, free-living Biological nitrogen (N) fixation (BNF) in soil and litter tends to decrease when substrate N concentrations increase, whereas increasing phosphorus (P) and molybdenum (Mo) soil and litter concentrations have been shown to stimulate free-living BNF rates. Yet, very few studies explored the effects of adding N, P, and Mo together in a single large-scale fertilization experiment, which would teach us which of these elements constrain or limit BNF activities. At two distinct forest sites in French Guiana, we performed a 3-year in situ nutrient addition study to explore the effects of N, P, and Mo additions on leaf litter and soil BNF. Additionally, we conducted a short-term laboratory study with the same nutrient addition treatments (+N, +N+P, +P, +Mo, and +P+Mo). We found that N additions alone suppressed litter free-living BNF in the field, but not in the short-term laboratory study, while litter free-living BNF remained unchanged in response to N+P additions. Additionally, we found that P and P+Mo additions stimulated BNF in leaf litter, both in the field and in the lab, while Mo alone yielded no changes. Soil BNF increased with P and P+Mo additions in only one of the field sites, while in the other site soil BNF increased with Mo and P+Mo additions. We concluded that increased substrate N concentrations suppress BNF. Moreover, both P and Mo have the potential to limit free-living BNF in these tropical forests, but the balance between P versus Mo limitation is determined by site-specific characteristics of nutrient supply and demand.

Mots-clés Agrovoc : Fixation de l'azote, litière végétale, forêt tropicale, litière forestière, substance nutritive, Fixation biologique de l'azote, biologie du sol, substrat de culture, phosphore

Mots-clés géographiques Agrovoc : Guyane française, France

Agences de financement européennes : European Research Council

Agences de financement hors UE : Ghent University, Research Foundation Flanders, Agence Nationale de la Recherche

Projets sur financement : (EU) Effects of phosphorus limitations on Life, Earth system and Society, (FRA) CEnter of the study of Biodiversity in Amazonia, (FRA) ANAEE-Services

Auteurs et affiliations

• Van Langenhove Leandro, University of Antwerp (BEL) - auteur correspondant
• Depaepe Thomas, Ghent University (BEL)
• Verryckt Lore T., University of Antwerp (BEL)
• Vallicrosa Helena, CREAF (ESP)
• Fuchslueger Lucia, University of Vienna (AUT)
• Lugli Laynara F., National Institute of Amazonian Research (BRA)
• Bréchet Laëtitia, INRAE (FRA)
• Ogaya Romà, CREAF (ESP)
• LLusià Joan, CREAF (ESP)
• Urbina Ifigenia, CREAF (ESP)
• Gargallo‐Garriga Albert, CREAF (ESP)
• Grau Oriol, CIRAD-ES-UMR Ecofog (GUF)
• Richter Andreas, University of Vienna (AUT)
• Peñuelas Josep, CREAF (ESP)
• Van Der Straeten Dominique, Ghent University (BEL)
• Janssens Ivan A., University of Antwerp (BEL)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/607058/)

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