0000000000521916
AUTHOR
Claire Chenu
Collecte et valorisation « open science » des données de décomposition des litières végétales dans les sols
National audience; La décomposition des litières végétales dans les sols a été largement étudiée notamment en raison de l’importance des processus environnementaux mis en jeu. En effet, le recyclage des biomasses végétales permet tout d’abord d’alimenter la biodiversité microbienne des sols. Ces microorganismes sont essentiels pour la qualité des sols puisque les mécanismes de dégradation dont ils sont à l’origine permettent le bouclage des cycles biogéochimiques en assurant la nutrition minérale des cultures en place. De plus, le recyclage des litières végétales alimente le puits de carbone du sol, ce qui contribue à limiter la teneur en dioxyde de carbone de l’atmosphère impliqué dans le …
La sensibilité des communautés microbiennes à une augmentation de la température augmente quand la biodégradabilité de la ressource organique baisse
La sensibilité des communautés microbiennes à une augmentation de la température augmente quand la biodégradabilité de la ressource organique baisse. 12. Journées d'Etude des Sols
Les sols et la préservation de la biodiversité
Les sols et la préservation de la biodiversité. Journée Mondiale des Sols
Spatial variability of 2,4-dichlorophenoxyacetic acid (2,4-D) mineralisation potential at a millimetre scale in soil
Abstract We analysed the ability of soil units of millimetre size to mineralise a herbicide, 2,4-D, using incubations of individual aggregates (2–7 mm diameter) and 6×6×6 mm 3 cubes dissected from soil cores, under standard conditions. Mineralisation of 14 C-ring labelled 2,4-D was measured using a barite paper trap and a Phosphorimager to record the evolved 14 C-CO 2 from these very small soil samples. We found a large variability of 2,4-D mineralisation potential between aggregate size classes, between individual aggregates of the same size and between the different dissected cubes from a given core. We explained this variability by an uneven distribution of the degrading microorganisms a…
Organic carbon dynamics in soil particle-size separates of sandy Spodosols when forest is cleared for maize cropping
Summary In southwest France, much of the forest lands on sandy Spodosols has been converted to continuous maize cropping in the last few decades. To evaluate the impacts of such change on the content and properties of the soil organic matter, we compared the amount of organic carbon and 13C natural abundance in soil and particle-size separates at three locations, selected on the basis of different contents of 0–50 μm particles (clay + silt). After three decades of cultivation, the amount of carbon from the forest pools (Cf) decreased by about 60%, attributable mainly to easily degradable material in sand-sized fractions (−70%). However, a recalcitrant residue remained in soil at a constant …
Effect of carbon source supply and its location on competition between inoculated and established bacterial strains in sterile soil microcosm
The aim of this work was to study how the location of a carbon source and of bacterial cells in soil can enhance the growth of a bacterial inoculum. Studies were performed using irradiated soil and two pairs of strains of Bradyrhizobium japonicum and Pseudomonas fluorescens. For each species, an antibiotic-resistant mutant was used as inoculant and introduced into a sterile soil pre-colonised with its parent strain. The inocula and a glycerol amendment were introduced together or separately into soil using porous microgranules or by spraying a suspension onto the bulk soil. Competition was assessed by plate counts of both inoculant and established populations. Both B. japonicum and P. fluor…
La collection historique d’échantillons de sols de l’essai patrimonial des ‘42 parcelles’ (INRAE, Versailles) : une machine à remonter le temps...
Following three previous papers (van Oort et al., 2016, 2017, 2020) dealing with current soil characteristics and geochemical budgets in surface horizons, as well as the impacts of fertilization in subsurface horizons in soils of INRAE’s long term bare fallow experiment (the 42-plots trial), we now present some chronological aspects of soil evolution at the soil’s surface since 1928. For that, we analyzed several series of about 15 samples from the historical sample archive for 10 representative treatments: fertilizers with acidifying effects (ammonium sulphate, ammonium phosphate), fertilizers with dispersive effects (sodium nitrate, sylvinite, and potassium chloride), superphosphate, amen…
Options for reducing greenhouse gas emissions from the agricultural sector: abatement potential and cost of technical measures
National audience
Variability of pesticide mineralization in individual soil aggregates of millimeter size
The aim of this study was to compare the 2,4-D mineralization in individual aggregates of millimeter size (3 size classes and 96 aggregates per size class). 14 CO 2 coming from the mineralization of 14 C ring-labeled 2,4-D and evolved by each aggregate incubated in microtiter plates was trapped with barium hydroxide on filters and measured using a Phosphorimager. We observed an important variability of mineralization in aggregates of each size class and in the different size classes of aggregates. The main factors responsible for these fluctuations could be a heterogeneous distribution of degrading microorganisms or of available carbon necessary for cometabolism.
Measurement, Reporting and Verification (MRV) of soil carbon
Measurement, Reporting and Verification (MRV) of soil carbon. International Scientific Conference Our under Common Climate Future Change
Soilμ3d project: emergent properties of soil microbial functions from 3d modelling and spatial descriptors of pore scale heterogeneity
International audience; The reduction of greenhouse gas emissions by improving the efficiency of agricultural systems through robust ecologically-based management practices represents the most important challenge facing agriculture. Models are needed to evaluate the effects of soil properties, climate, and agricultural management practices on soil carbon and on the nitrogen transformations responsible for GHG emissions. Models of Carbon and nitrogen cycles in soils need improvements so they can provide more accurate and robust predictions. They use empirical functions which account for the different environmental factors that affect microbial functions. However, these types of function have…
2,4-D impact on bacterial communities, and the activity and genetic potential of 2,4-D degrading communities in soil
The key role of telluric microorganisms in pesticide degradation is well recognized but the possible relationships between the biodiversity of soil microbial communities and their functions still remain poorly documented. If microorganisms influence the fate of pesticides, pesticide application may reciprocally affect soil microorganisms. The objective of our work was to estimate the impact of 2,4-D application on the genetic structure of bacterial communities and the 2,4-D-degrading genetic potential in relation to 2,4-D mineralization. Experiments combined isotope measurements with molecular analyses. The impact of 2,4-D on soil bacterial populations was followed with ribosomal intergenic…