Search results for " Trait"
showing 10 items of 764 documents
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…
Pesticides sur blé tendre d'hiver, diversité dans le détail
2013
Contexte -L’analyse des pratiques d’application des pesticides (herbicides, fongicides, insecticides, ré-gulateurs) sur le blé tendre d’hiver (BTH) a été réalisée à partir de données d’en-quêtes annuelles sur une petite zone agricole en Côte-d’Or. Etude - L’étude a porté sur 294 parcelles appar-tenant à 13 exploitants pour la période 2004-2011. L’indice retenu pour carac-tériser l’usage des pesti-cides est l’IFT (indice de fréquence de traitements).
Cropping system dynamics, climate variability, and seed losses among East African smallholder farmers: a retrospective survey.
2014
Abstract Climate variability directly affects traditional low input and rain-fed farming systems, but few studies have paid attention retrospectively to the cropping system’s ability to mitigate climate risk. This study analyzes the impacts of rainfall variability on farmers’ seed variety losses over time, considering changes in smallholder farming systems. The cropping system dynamics, in favoring maize at the expense of sorghum and pearl millet, have induced an increasing risk of seed loss during drought. Combining ecological anthropology and climatology, a retrospective survey asking farmers about the period 1961–2006 was carried out at three altitudinal levels (750, 950, and 1100 m) on …
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…
Characterisation of phenotypic plasticity in seedling stage of native and invasive populations in Ambrosia artemisiifolia L.
2012
Increased phenotypic plasticity has often been invoked as an hypothesis to explain the capacity of alien invasive plant species to colonize new environments, because it may enhance the ability of plants to cope with new biotic and abiotic conditions. Following this hypothesis, alien invasive populations should be represented by more plastic genotypes than populations in the native range. In annual species, the seedling stage is of crucial importance for population dynamics but surprisingly very few studies have investigated differences in phenotypic plasticity on seedling traits. Based on populations from the native range (North America) and the invasive range (France) of Ambrosia artemisii…
Biological causes of cornflower regression
2012
International audience; Agroecosystems are currently experiencing high biodiversity loss. This decline results from intensive cropping systems. However, not all the anciently present weeds respond similarly. There should be specific biological traits that render some species more prone to disappear from arable fields than others. Investigating the biological causes of regression could inform about management strategies in changing agricultural farming systems. In this report we focus on cornflower (Centaurea cyanus) that is an emblem of the flora associated with traditional cereals in Europe. It is currently disappearing from Western regions. Several traits were investigated as seed longevi…
Changing agricultural practices modifies the species and trait composition of the weed flora. A simulation study using a model of cropping system eff…
2012
International audience; Cropping systems change to adapt to socio-economical and environmental constraints (e.g. simplified tillage) and to profit from technological innovations (e.g. genetically-modified crops). These changes can result in unexpected side-effects which are difficult to determine in fields. The objective of the present study was to use a model, FLORSYS, to evaluate such impacts ex ante on weeds. FLORSYS quantifies the effects of crop succession, management techniques and climate on multi-specific weed dynamics over the years; it was parameterized with functional relationships predicting model parameters (e.g. seed mortality) from species traits (e.g. seed coat thickness). C…