0000000000121314
AUTHOR
Guy Richard
Effect of environmental conditions on Alopecurus myosuroides germination - I : Effect of temperature and light
International audience
Effect of environmental conditions on Alopecurus myosuroides germination - II : Effect of moisture conditions and storage length
International audience
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…
Modelling black-grass (Alopecurus myosuroides Huds.) germination and emergence, in interaction with seed characteristics and movements and soil climate
National audience
Morphological characterisation of soil structure in tilled fields: from a diagnosis method to the modelling of structural changes over time
Characterisation of soit structure within the tilled layer of cultivated fields is crucial because the importance of this soil characteristic on the biological, chemical and physical properties of the soil and its repercussions on water cycle, root growth and functioning. We present in this paper a method for field characterisation of soil structure. This method, practised since the 1970s, was designed for field diagnosis of the effects of cropping systems on soil structure. It is based on a stratification of the observation face of a pit dug perpendicular to the direction of tillage and traffic: spatial compartments are distinguished, according to the nature of the mechanical stresses they…
Hétérogénéité spatiale de l'activité des microorganismes décomposeurs des matières organiques dans les sols. Mise en évidence, paramètres explicatifs
AIP Ecosol 1995-1998 : rapport final de projet *INRA Unité de Science du Sol Versailles Diffusion du document : INRA Unité de Science du Sol Versailles; National audience
Modelling vertical and lateral weed seed movements during mouldboard ploughing with a skim-coulter
Abstract The vertical distribution of weed seeds in soil is crucial because seedling emergence varies with seed depth, whereas lateral soil displacement during mouldboard ploughing contributes to weed dispersal within the tilled field. In order to model vertical and lateral seed displacements during ploughing, an existing model describing soil particle movements for different ploughing characteristics (depth and width) and soil structures was adapted to integrate the effect of a skim-coulter. This model was tested in two field trials, in Northern France, using coloured plastic beads to imitate weed seeds. The trial in Dijon was set up on an eutric cambisol and comprised both compacted and u…
Environnement et agronomie au XXIe siècle, et maintenant ?
International audience; Cette conclusion de l'ouvrage "Une agronomie pour le XXI° siècle" dresse un panorama des enjeux futurs pour la discipline.