Stephane Cordeau

Visiting Scientist, 2016
sc2239@cornell.edu

Education
PhD in Agronomy and Ecology, University of Burgundy (Dijon, FR), 2010
MSc in Agronomy, National Institute of Agronomy of Paris-Grignon (FR), 2007
Engineer’s degree in Agronomy, National Institute of Agronomy of Paris-Grignon (FR), 2007

Research Interests
Working with the Sustainable Cropping Systems Lab in 2016, I investigated the impact of cropping systems on weed communities. I mainly focus on the effect of cropping systems in 3 gradients: (i) reduction of tillage (from conventional tillage to continuous no-till); (ii) increasing use of cover-crops (from cropping systems containing only cash crops to all ranges of cover-cropping); (iii) reduction of herbicide (from conventional to organic systems). The fundamental objectives of my research are to understand how weed communities evolve (through abundance, richness, biomass, evenness, and traits) in systems where farmers reduce tillage, use cover crops, and tend to reduce their reliance on herbicides. My practical objective is to design new cropping systems reducing the use of herbicides in cropping systems where farmers implement no-till and cover crops, and assess the sustainability of these systems in terms of weed management and economics.

I work within the cropping system scale to the plant-plant interaction scale. We use a variety of methodologies that include broad-scale weed surveys, long-term field experiments, field plot factorial experiments, pot experiments outside or in greenhouse, and high-throughput phenotyping.

Past Research
My PhD addressed weeds in semi-natural habitats such as field margins. I put into practice agronomic and ecological concepts to highlight the potential role of field margins as a weed reservoir for adjacent fields. I also explored how weed communities evolve in these margins, whether facing disturbance (yearly mowing), competition (margins sown with highly competitive grass species), or absence of tillage.

Publications
Cordeau S., Guillemin J.-P., Reibel C., Chauvel B. 2015. Weed species differ in their ability to emerge in no-till systems that include cover crops. Annals of Applied Biology doi:10.1111/aab.12195

Cordeau, S., Dessaint, F., Munier-Jolain, N., 2015. Long-term assessment of integrated weed management cropping systems in France. Aspects of applied biology 128: Valuing Long-Term sites and Experiments for Agriculture and Ecology, 275-278.

Cordeau, S., Deytieux, V., Lemanceau, P., Marget, P., 2015. Towards the establishment of an experimental research unit on Agroecology in France. Aspects of applied biology 128: Valuing Long-Term sites and Experiments for Agriculture and Ecology, 271-273.

Petit S., Munier-Jolain N., Bretagnolle V., Bockstaller C., Gaba S., Cordeau S., Lechenet M., Mézière D. and Colbach N. 2015. Ecological intensification through pesticide reduction: weed control, weed biodiversity and sustainability in arable farming. Environmental Management DOI 10.1007/s00267-015-0554-5

Badenhausser I., Gross N., Cordeau S, Bruneteau L. and Vandier M. 2015. Plant-grasshopper interactions in sown grass margin strips are mediated by plant diversity and identity. Arthropod-Plant Interactions. DOI 10.1007/s11829-015-9376-x

Cordeau S., Petit S., Reboud X. and Chauvel B. 2012. Sown grass strips harbour high weed diversity but decrease weed richness in adjacent crops. Weed Research 52: 88-97.

Badenhausser I. and Cordeau S. 2012. Sown grass strip-A stable habitat for grasshoppers (Orthoptera: Acrididae) in dynamic agricultural landscapes. Agriculture Ecosystems & Environment 159:105-111.

Cordeau S., Petit S., Reboud X. and Chauvel B. 2012. The impact of sown grass strips on the spatial distribution of weed species in adjacent boundaries and arable fields. Agriculture Ecosystems & Environment 155: 35-40.

Cordeau S., Reboud X. and Chauvel B. 2011. Farmers’ fears and agro-economic evaluation of sown grass strips in France. Agronomy for Sustainable Development 31:463-473.

Cordeau S., Reboud X. and Chauvel B. 2010. Relative importance of farming practices and landscape context on the weed flora of sown grass strips. Agriculture Ecosystems & Environment 139:595-602.