Search results for "Traits"
showing 10 items of 548 documents
Trait distribution within winter wheat fields can partly be explained by disturbances and competition for resources
2013
International audience; Weed species are not homogeneously distributed into field elements (Cordeau et al. 2012)*.In a field, weed species are mainly competing with the crop and constrained by management practice (i.e.disturbances). In the crop edge, less unfavorable conditions for weed development (i.e.absence of direct crop competition,l ess frequent disturbances could explain the greater diversity of weeds.To understand this observation, a functional approach base dont raits known to respond both to disturbances and to competitive or facilitative interactions can be used.Our assumptions are that(i)the crop edge is likely to all owawi derrange of ecological strategies thus promoting speci…
Quantification des flux d’azote induits par les cultures de légumineuses et étude des traits explicatifs
2016
National audience; Dans le contexte de la transition agroécologique en faveur de systèmes de culture plus économes en intrants azotés, la réintroduction des légumineuses a un rôle majeur à jouer pour atteindre la durabilité de ces systèmes. Peu de références sont actuellement disponibles sur les intérêts agronomiques et écologiques des différentes espèces, notamment à l’échelle de la rotation. Dans ce cadre, notre objectif général consiste à mieux quantifier les flux d’azote impliqués au cours et après culture de légumineuses, et ce pour une gamme élargie d’espèces. Notre travail expérimental portera donc sur la caractérisation des flux d’azote induits dans le sol et dans les cultures de lé…
Mise en évidence du rôle de la diversité dans la dynamique des communautés d'adventices et des interactions adventices/cultures
2020
The main challenge of 21st century agriculture is to provide sufficient food for a growing to identify cropping systems which maintain crop productivity, minimize reliance on synthetic herbicides and nitrogen fertilizers, and promote weed diversity. We hypothesized that cropping system diversification, either at the annual scale through the introduction of cover crops, or at the plurennial scale through a diversification of the crop sequence and associated weed management tools, could be a viable means to reach these objectives. More specifically, we hypothesized that cropping system diversification could (i) contain weed abundance and thereby, allow a reduction of herbicide use and an incr…
Assessing short- and long-term repeatability and stability of personality in captive zebra finches using longitudinal data
2012
11 pages; International audience; Assessing behavioural consistency is crucial to understand the evolution of personality traits. In the present study, we examined the short- and long-term repeatability and stability of two unrelated personality traits - exploratory tendencies and struggling rate - using captive female zebra finches (Taeniopygia guttata). We performed two experimental sessions of behavioural tests with a 7-mo interval, which represents up to one quarter of a zebra finch's life expectancy. We showed that, overall, exploratory tendencies and struggling rate were significantly repeatable in the short term. However, only exploratory tendencies were repeatable in the long term. …
Weed seeds ability to emerge on the soil surface
2015
International audience; Annual weeds have to produce seeds each year to maintain their populations. These seeds fallon the soil surface. Seeds exposed to light during their moistening (i.e. caused by rain) bettergerminate than seeds in the darkness (i.e. buried). However, rare studies quantified the unique andcombined effects of light, moisture and burial depth on the germination process. We investigated,in a greenhouse experiment in 2014, the impact of seed moisture (Moistened vs. Dried), lightduring moistening (Darkness vs. Light) and burial depth (Buried vs. Surface) on germination of 12annual weed species contrasted on their seed traits and germination periods (Alopecurusmyosuroides Hud…
Comparaison de la multifonctionnalité relative aux flux azotés induits par dix cultures de légumineuses
2019
National audience; Les légumineuses sont à l’origine de fonctions uniques et/ou complémentaires à celles d’autres groupes d’espèces (céréales, oléagineux) sur les-quelles reposent des services écosystémiques rela-tifs à l’azote. Pourtant, le choix des légumineuses à graines selon leur aptitude à fournir ces services écosystémiques reste difficile compte tenu du manque de références sur une diversité d’espèces. Au cours d’une succession culturale de deux ans (lé-gumineuse –blé), cinq flux azotés et plusieurs traits de plantes considérés comme explicatifs de ces flux azotés ont été mesurés, afin de dresser le profil fonctionnel de dix espèces de légumineuses à graines. Il s’agissait de compre…
Impacts of climate change on the performance of an insect pest and associated consequences for tritrophic interactions
2019
Global warming poses a major challenge to living organisms, particularly for ectothermic animals like insects, whose physiology and behaviour are closely related with direct thermal surroundings. This thesis aims at experimentally investigating the impacts of climate change on the overall performance of a major grapevine pest, the European grapevine moth (Lobesia botrana), and the associated consequences for interactions involving this phytophagous insect and adjacent trophic levels, more specifically natural enemies (parasitoids). The experiments conducted focus on three facets of climate change: an increase in mean temperature, an alteration of daily thermal range, and the occurrence of h…
Transition to conservation agriculture : changes in cropping practices and responses of weed communities
2020
Conservation agriculture is a farming system based on the continuous and simultaneous application of three principles: minimal soil disturbance, continuous residue cover on the soil surface and diverse crop rotations. Adoption of this form of sustainable agriculture in France since the 2000s has been hampered by a number of constraints, including the development and management of weed populations. From an agronomic point of view, the adoption of conservation agriculture and associated abandonment of tillage results in a significant loss of weed management practices for farmers. From an ecological point of view, its application can modify all the assembly processes that act on weed communiti…
Quantification des flux d’azote induits par les cultures de légumineuses et étude de leurs déterminants : comparaison de 10 espèces de légumineuses à…
2019
In the context of agroecological transition, the reintroduction of legume crops should play a key role in cropping system sustainability by allowing a reduction of nitrogen (N) inputs. But few references are available concerning the agronomical and ecological services provided by a wide range of legume crops, particularly within crops succession scale. Thus, the main objective of our study is to quantify the N fluxes during and after the legume crops taking into account 10 legume crops (peas, lupin, faba bean, soybean...). Our experiment consists in i) quantifying symbiotic N fixation depending on the amount of soil inorganic N, the mineralisation of N present in legume crop residues after …
Highlighting the role of diversity in driving weed dynamics and weed-crop interactions
2017
EAGESTAD INRA; Weeds are responsible for crop losses and their management, mainly through herbicide applications, has led to resistances and environmental impacts. Integrated Weed Management encourages the use of “many little hammers” such as crop rotation, mechanical weeding, stale seedbed technique and delayed sowing … i.e. more complex and diversified cropping systems, in order to increase cropping system sustainability. However, research is still required to test the effectiveness of combinations of these alternative tactics in a wide range of agricultural contexts. Furthermore, the cropping system approach considers all these individual hammers, whose effects on agricultural weeds have…