Search results for "Weed"
showing 10 items of 321 documents
Accompagner les réseaux DEPHY-FERME et DEPHY EXPE dans la caractérisation de l’effet des systèmes de culture sur la flore adventice
2015
To characterize weed pressure in agricultural fields of the DEPHY Ecophyto networks, the "weeds" working group of the CASIMIR project, helped by crop and weed experts working for the french crop institutes, developed two methods (CASIMIR DEPHYFARM and CASIMIR DEPHYEXPE) to survey weeds in main crops. The objectives of these methods are: (i) with shortterm concern, assess the efficacy of farming practices to manage weeds within the crop season, (ii) with longterm concern, assess the effect of cropping system (farming practices and crop sequence) on the dynamic of the weed communities. The CASIMIR DEPHYFARM method is based on walk away surveys made within a 2000m² reference plot where t…
Modelling the effects of cropping systems on the dynamics of a parasitic weed, Phelipanche ramosa, in interaction with the non-parasitic weed flora
2010
International audience; The current decrease in herbicide use may increase and diversify weed flora in crops as well as companion bioagressors spreading via weeds. Among these bioagressors is Phelipanche ramosa, a parastic plant which is very harmful on oilseed rape. The objective of the present work was to develop a model (called PHERASYS) of the effects of cropping systems on parasite dynamics, in interaction with non-parasitic weed hosts. The structure of the first model version was based on models developed for other parasitic plants and on FLORSYS which quantifies the effects of cropping systems on non-parasitic weed flora. PHERASYS was parametrized with preliminary values from literat…
Aerial multispectral imagery for site specific weed management
2017
AGROSUPSPEEAGESTADCT1DOCT; In an agroecological context (French Law on the Future of Agriculture), the reduction of herbicide uses become a crucial issue. It requires developing new technologies allowing a better knowledge of the field. The company AIRINOV, specialized in use of Unmanned Aerial Vehicle (UAV) dedicated to precision agriculture wants to explore a new approach by UAV to localize weed infestation areas. This work aims to develop a method analyzing images acquired by UAV to detect and map weeds in a field. The study is carried out on crops widely grown in France and requiring weed control at a young state of the plant : maize, sunflower and sugar beet. With its on-board sensors …
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…
Intra-row weed detection in wheat at early growing stage using imaging system
2017
AGROSUPSPEEAGESTAD; In the present agroecological context, the reduction of herbicide uses becomes a substantial issue. For weed control and site specific weed management the development of new technologies is required to identify individual plant. Although many crop/weed discrimination methods have been developed, the automatic intra-row weed detection is still a challenge, particularly in wheat. An imaging system is developed to detect black grass in wheat at early growing stage. The technique mimics the method used by a human expert in such conditions. Thus, the hypocotyl diameter was used as distinguishing criterion. For experiments, the seeds of black grass and wheat were sown in recta…
Quelles pratiques agricoles pour préserver les peuplements riches en espèces messicoles ?
2016
A consequence of the agricultureal intensification of the second part of the XXth century is the depletion of some species linked to arable fields. These species called “segetal” are considered since 2012 under a National Action Plant (PNA). A survey has been conducted to explore the relationships between these segetal weeds and agricultural practices. It involved 159 farm plots for two years in three regions having contrasted climates, soils and farming systems. Data of species richness are presented in relation to agricultural practices. They cannot allow hierarchical ranking of the most favourable practices, whatever the region, but rather the presence of segetal weeds is associated with…
Soil weed seedbank composition and structure in a long-term nutrient management experiment
2016
EAGESTAD; Weed communities can be influenced by nutrient availability, nutrient form (e.g. ammonium vs. nitrate), amendment timing, amendment type, and by immigration of seeds during amendment applications. New York ranks third in the United States in the number of dairy cows and thus dairy manure applications are prevalent throughout the state. The objective of this work was to compare the effect of dairy manure and inorganic fertilizer on soil weed seedbank composition and structure in a long-term nutrient management experiment. The field experiment was initiated in 2001 at the Cornell Musgrave Research Farm in Aurora, NY and compared ten treatments in a corn-alfalfa rotation using a rand…
Variation of post-dispersal weed seed predation according to weed species, space and time
2008
International audience; Post-dispersal seed predation is an important source of mortality in plant populations. If this phenomenon is better known in tropical and woody systems, information is lacking for weeds in French agrosystems. In this paper, we evaluated seed predation variability in an organic wheat field by conducting experiments on weed seed preference and on spatial and temporal variation in predation rates. Weed seed predation preferences followed a species rank: Viola arvensis = Stellaria media > Alopecurus myosuroides = Chenopodium album > Sinapis arvensis = Anagallis arvensis = Galium aparine > > Plastic globules (for control), with weekly mean predation rates between 19 and …
Archéophytes et néophytes.Pour une nouvelle détermination des marqueurs polliniques de l'anthropisation. Le cas des milieux cultivés et rudéraux de F…
2007
297p. de synthèse, annexes p.299-414, 15 articles en soumission Diplôme : Dr. d'Universite
Behind the French National Action Plan in favor of Messicoles, the rare arable weeds
2013
Earliest concerns about weed species disappearing from the fields in France rose in the 70s, but they gained recognition in 1993 only with a scientific meeting entitled: “Are weeds worth protecting?“. Thereafter, the French Ministry of Environment initiated a data collection and expert discussion through the network of the National Botanic Conservatories (scientific structures in charge of the survey and preservation of the wild flora and habitats). This approach recently ended with the release of a 241 pages document presenting the state of the art about 102 species strictly associated with arable lands in France: the “Messicoles” (from Latin words meaning “living in cereals”). In 2009 and…