Search results for "agroecology"

Modélisation des effets des systèmes de culture sur la dynamique de la plante parasite orobanche rameuse en interaction avec les adventices

2019

Reducing pesticide use is a major challenge in agriculture and involves developing more sustainable methods that rely on non-chemical cropping techniques and biological regulations according to agroecological principles. Branched broomrape (Phelipanche ramosa (L.) Pomel) is a root parasitic plant which infects crops and causes dramatic yield losses worldwide. Managing broomrape is complex because it requires combining several cropping techniques whithin a global weed management strategy because broomrape is also able to infect non-parasitic weeds. The aim of this thesis was to stynthetize knowledge on branched broomrape dynamics in agroecosystems and to aggregate it within a mechanistic mod…

Synchronie entre l'offre et la demande dans le cycle des nutriments: apprendre des écosystèmes naturels pour construire des agrosystèmes durables

2023

Redesigning agrosystems with more ecological regulations can help feed a growing population, preserve soils for future productivity and reduce environmental impacts. However, guidelines for redesigning agrosystems from natural systems are limited. Reviewing the last knowledge of ecosystem functioning, we outlined four ecological systems synchronizing the supply of soluble nutrients by soil biota to fluctuating plant nutrient demand. This synchrony limits deficiencies and excesses of soluble nutrient, which usually penalize both production and regulating services of agrosystems such as nutrient retention and soil carbon storage. We detail how ecological systems promoting synchrony can be ins…

La pollinisation du cassis : État des lieux dans un contexte de changements anthropiques.

2019

Cultivated plants are part of their agroecosystem. Recent anthropic changes modified and decreased the wildcompartment of agroecosystems leading to a lowering of ecosystemic services such as pollination. Blackcurrant ispollinated at least partially by insects. In a study on 8 sites in Côte-d’Or, Burgundy, France we showed that pollinatordensity is lower than 0.5 pollinators per minute of observation in blackcurrant orchards. Blackcurrant are preferentiallyvisited by Bombus sp. and to a lesser extent by Andrena and Apis sp. Comparison of pollinator abundance between2018 data and data from ancient publications show that even if the floral abortion rate did not vary significantly, thenumber of…

Co-développement d'un modèle d'aide à la décision pour la gestion intégrée de la flore adventice. Méta-modélisation et analyse de sensibilité d'un mo…

2018

The main threat to agricultural crops are weeds with herbicides being the primary cropping management practice. Due to the negative impact of herbicides on health and environment, their use must be reduced. To replace herbicides, numerous cropping practices need to be implemented. This makes weed management more complicated and, together with necessity of scheduling operations at long-term and the multiplicity of cropping system impacts, explains why models are so useful for designing innovative cropping systems. The aim of this thesis was to develop a Decision Support System (DSS) intended for crop advisors to help design cropping systems that are less dependent on herbicides. Our approach…

Contribution des pollinisateurs dans la production de colza et de tournesol en zone atelier « Plaine et Val de Sèvre »

2018

Insect pollination is essential for over 70% of crops around the world. However, the contribution of pollinators to crop production and the insects involved in crop pollination have rarely been studied. Moreover, assessments of pollinator contributions have mostly been conducted on a small scale or under simplified conditions, which do not represent the real contributions at the field scale and do not take into account possible interactions between pollinators and farming practices. The aim of this study is to quantify directly under field conditions, the contribution of pollinators in two crops frequently cultivated in Europe: oilseed rape and sunflower. Estimations are realized both at th…

Elucidating the genetic determinism of the plasticity of seed proteins in response to the environment using Medicago truncatula

2019

International audience; Legumes are able to produce high-protein seeds without nitrogen fertilizer through root symbiosis with nitrogen-fixing rhizobia. Rich in lysine, these proteins are used for human nutrition and animal feed. However, instability of seed protein yield and quality due to environmental fluctuations limits the wide adoption of legumes in Europe. Breeding efforts are needed to optimize and stabilize seed nutritional quality. We have studied the plasticity of protein content and composition of seeds from a collection of 200 ecotypes of Medicago truncatula grown under four controlled conditions (optimal, drought, and winter/spring sowing). A quantitative analysis of one-dimen…

A landscape-scale approach for linking farming strategies to weed communities and their contribution to ecosystem services

2019

National audience; Weeds present in agricultural fields provide habitats and trophic resources and as such contribute to the provision of ecosystem services such as pollination (quantity and quality of pollen and nectar in flowers) and biological control (seeds for pest natural enemies). The nature and amount of services provided depends on the floral composition of weed communities and this composition is driven by the combination of farming practices. Linking farming strategies to services is thus an important step to provide management guidelines for enhancing ecosystem services. We report here on such an analysis, based on agronomical and weed data collected annually in 70 field cores a…

Les réseaux mycéliens jouent ils un rôle dans la distribution des éléments nutritifs entre les graminées et les légumineuses ?

2017

Phenotyping in Agroecology

2012

International audience

Should we manage weeds for bees ?

2014

National audience