Search results for "HERBAGE"
showing 10 items of 25 documents
Defoliation-induced changes in carbon allocation and root soluble carbon concentration in field-grown Lolium perenne plants: do they affect carbon av…
2005
Summary 1It is hypothesized that defoliation-induced changes in plant carbon allocation and root soluble C concentration modify rhizosphere C availability and, further, the abundance and activity of soil microbes and their grazers. To test this hypothesis, field-grown Lolium perenne swards were defoliated twice during their second growing season at two nitrogen availabilities (added N or no added N). Plant, soil and microbial attributes were measured 2 and 4 days after the last defoliation, and nematode abundance was measured 6 days after the last defoliation. 2Defoliation decreased shoot production in plots where N was added, but had no significant effect in plots where N was not added. Ro…
GeneSys-Beet: A model of the effects of cropping systems on gene flow between sugar beet and weed beet
2008
A weedy form of the genus Beta, i.e. Beta vulgaris ssp. vulgaris (hence ''weed beet'') frequently found in sugar beet is impossible to eliminate with herbicides because of its genetic proximity to the crop. It is presumed to be the progeny of accidental hybrids between sugar beet (ssp. vulgaris) and wild beet (ssp. maritima), or of sugar beet varieties sensitive to vernalization and sown early in years with late cold spells. In this context, genetically modified (GM) sugar beet varieties tolerant to non-selective herbicides would be interesting to manage weed beet. However, because of the proximity of the weed to the crop, it is highly probable that the herbicide-tolerance transgene would b…
Les paradoxes du glufosinate et glyphosate. Comportement dans l'ambroisie à feuilles d'armoise
2006
BEHAVIOUR OF GLUFOSINATE ANDGLYPHOSATE IN COMMONRAGWEED:APPARENT PARADOXAND SURPRISES We examined the foliar epidermis of commonragweed (Ambrosia artemisiifolia L.) plants and studied the behaviour of the herbicides glufosinate and glyphosate in this species. Both leaf surfaces exhibited 3 types of trichomes, according to their size and shape. Epicuticular waxes appeared amorphous, which may explain high levels of spray retention. Glufosinate and glyphosate were rapidly and almost completely taken up by common ragweed leaves; half maximum uptake was nearly reached after 5 and 3 h, respectively. The longest trichomes were stained with AgN03, indicating the presence of hydrophilic domains, wh…
The maturity stage of the grass affects milk fatty acids of cows grazing a mountain grassland
2010
International audience; We aimed to quantify the effect of the growth stage of a mountain grassland pasture on the fatty acid (FA) composition of grass and milk. In June (growth) and October (regrowth), a mountain pasture was continuously grazed by six dairy cows in a strip grazing system. During June, the grass C18:3n-3 content decreased while C16:0, c9-C18:1 and C18:2n-6 content increased. During October, the grass FA composition was similar to that observed in the first part of June. During June, milk saturated FA (SFA) content increased while the sum of the trans FA and polyunsaturated FA (PUFA) content decreased, mainly due to the decrease in C18:3n-3 and c9t11-CLA percentages. At the …
Biodiversity-functioning relations in microorganisms
2006
The role of microorganisms as key components in the functioning of ecosystems and biodiversity is discussed. The latest methodologies developed to study microbial diversity and functioning of ecosystems are considered, as DNA extraction and isotope labeling, fluorescent in situ hybridization and microautoradiography, and tracking of a substrate labeled with a stable isotope. Investigations related to correlations between microbial diversity and functioning in situ are considered. An example is illustrated of a correlation of erosion of microbial diversity of natural microbial community in prairie soil and erosion of species diversity in an ecosystem.
La conférence du Columa 2013 racontée par des étudiants AgroSup-Dijon
2014
Document accessible depuis la notice de ProdInra : https://prodinra.inra.fr/?locale=en#!ConsultNotice:306111; La 22e conférence du Columa de l’AFPP, tenue à Dijon du 11 au 13 décembre 2013, a été suivie par des étudiants d’AgroSup-Dijon. Ils rendent compte ici de ce qu’ils en ont retenu. Ils analysent particulièrement les sessions : – « Nuisibilité » des adventices (indirecte, ex. : favoriser l’ergot, et directe). – « Cultures méditerranéennes et tropicales » (différences Dom-Tom/autres pays, techniques émergentes). – « Résistance » (extension, mécanismes, facteurs de risque). – « Transfert aux milieux » (facteurs de risque de pollution des eaux, suivis et modélisation pour les prévoir). – …
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 …
Raisonnement des pratiques et des changements de pratiques en matière de désherbage : regards agronomique et sociologique à partir d’enquêtes chez de…
2008
To ensure successful, more sustainable weed management practices, it is crucial to take account of farmer’s decision-making processes. Agronomists revealed that interviewed farmers had complex and various weeding programmes, and that, when designing these programmes, they integrated different time scales: the current year, the rotation, and the long term. They gave some light, too, on the decision-making processes and how it changes over time. Sociologists analyzed the way wine-growers bring about change from the cognitive angle and its bearing on interactive dialogue between the wine-growers themselves as well as with technical advisors
Biovigilance flore adventice le point dans trois bassins de production de colza
2013
EA SPE EcolDur; National audience
La lutte biologique contre l'ambroisie à feuilles d'armoise illustrée par l'exemple d'Ophraella communa: quels intérêts et quelles limites ?
2016
National audience; Common ragweed (Ambrosia artemisiifolia) was introduced in France over 150 years ago and its spreading across France now seems inexorable. The specific biology of this summer annual creates new problems for the managers of the various habitats where the plant can be found. The reduced possibility, or even the impossibility, to use traditional control means in certain environment conditions brings managers to consider biological control as one of the few possible means for slowing down the spread, or even pushing back the distribution area, of this invasive and allergenic plant. With Ophraella communa as an example, a reflection is presented on the benefit-risk balance of …