Search results for "sds"

Approche multicritère pour la caractérisation des adventices par imagerie

2019

La réduction des produits phytosanitaires représente un des enjeux majeurs du secteur agricole. Les plans gouvernementaux Ecophyto, Ecophyto II et Ecophyto II+ visent à réduire fortement leurs usages et les solutions actuelles ne permettent pas d’obtenir les résultats escomptés. La détection des adventices par imagerie est un des axes de travail devant permettre cette réduction. La qualité de la discrimination cultures/adventices est fortement liée au type de méthodes utilisées, à la résolution spatiale des images et au stade de développement des plantes présentes. L'objectif de ce travail, est donc d'évaluer l’impact des différents critères pouvant être extraits depuis des images acquises …

A method for the preparation of repacked soil cores with homogeneous aggregates for studying microbial nitrogen transformations under highly controll…

1998

International audience; he feasibility of studies on nitrate transformations during incubation in controlled conditions of air-filled porosity using a method of soil core preparation was investigated. Repacked cores were obtained by uniaxial confined compression in a cylindrical mould of a mass of calibrated and conveniently wet aggregates with a water content selected to saturate the textural porosity of the soil aggregates, imposing structural porosity and thereby producing controlled conditions of aeration. The principle and the descrip- tion of the incubation method are explained and some denitrification and respiration data obtained with low and increasing OZ partial pressures are pres…

Effets simultanés de niveaux croissants de glucose et de pressions partielles en oxygène sur la dénitrification et la réduction dissimilative du nitr…

1998

International audience; Dissimilatory nitrate reduction to ammonium (DNRA) and its importance in comparison to denitrification were studied in soil samples artificially repacked to control water potential and porosity, and incubated for 72 h. Labelled nitrate (100 mg N.kg-’ dry soil, 21.8 % 15N in excess) and increasing levels of glucose-C (250, 500 and 1 000 mg glucose-Ckg-’ dry soil) were initially added to the soil samples to obtain increasing glucose-C/nitrate-N ratios of 2.5,5 and 10, which were then subjected to different 0, partial pressures (0,0.5, 1.0 and 2.0 % (v/v)). The results confirmed the good reproducibility of the experimental condi- tions using this method. Denitrification…

Segetal plant conservation in arable fields: functional role, farmers’ perception and farming systems

2014

International audience; Segetal plants, or “messicoles” as they are known in French, are weedy inhabitants of wheat crops (mainly winter cereals). The national list of segetal species includes 102 taxa; of which 7 are extinct, 52 threatened, 30 to be kept under close observation and 12 abundant. Data on their distribution indicates that they are mostly in decline due to intensive farming systems. As their survival is intrinsically linked to farming systems, we need to improve knowledge on their relationships with land management in order to establish a sound scientific basis for protection tools, to support and guide farmer conservation measures and to disseminate concerns for segetal biodi…

Comparative effect of inorganic N on plant growth and N2 fixation of ten legume crops

2018

International audience; [pas de résumé]

Comparison of different tillage systems in organic farming : effect of soil structure and organic matter repartition on soil micro-organisms and thei…

2009

Over the last decades, the surface traditionally ploughed has tended to decrease and replaced by shallow working tillage techniques without soil inversion, i.e., no tillage or reduced tillage with tines or discs. These techniques were mostly developed in conventional farming systems but nowadays they are also developed in organic farming systems. Nevertheless, these tillage techniques could generate crop nutrients deficiencies and a deterioration of soil structure, especially during the first years of their application. As the use of synthetic fertilizers is forbidden in organic farming, a decrease of the soil fertility could be very detrimental for crop growth. Indeed, soil micro-organisms…

Épisodes pluvieux intenses, érosion des sols et viticulture

2020

Publication de la Chaire UNESCO "Culture et Traditions du Vin" de l'Université de Bourgogne et du Centre Georges Chevrier UMR CNRS/uB 7366.; National audience

Soil Organic Matter in Mediterranean regions

2015

A database for the herbicide use in France

2013

SPEEAEcolDur; International audience

Réduction du nombre de molécules herbicides : conséquences par culture. Problématique particulière de la gestion de la flore adventice

2013

All national and European legislations contribute to the present reduction in the available herbicide number. This evolution leads to the decrease in the number of chemical families and to a dramatic reduction of the number of modes of action in some crops or crop rotations. This could lead to the selection of new herbicide resistances. So we may find contrasted situations: crops weeded with only a few herbicides or some herbicides used in almost all crops. The drastic reduction in the available active ingredients without taking into account the benefit-risk ratio or without planning realistic alternative solutions may create tougher agronomic constraints. A data base built up from all the …