Diversifying crop rotations with temporary grasslands - Université de ...

the ‘Chizé’ region in Western France, that were realized in collaboration with other scientists
and students within the framework of the ‘ECOGER’ research project running from 2006 to
2009 (see ‘Context and Funding’ at the beginning).
The second research approach (C.II) is based on a field experiment designed to compare weed
population dynamics between annual and perennial crops with different management options
on smaller temporal and spatial scales and with higher temporal and spatial resolutions. The
experiment was conducted from 2006 to 2009 on the INRA experimental farm in Dijon-
Epoisses. It allows also analyzing several of the hypothetical underlying mechanisms (c.f.,
section A.IV.2).
Two of these hypothetical mechanisms will also be analyzed in more detail in the two last
chapters. Chapter C.III addresses the impacts of cutting on the survival and regrowth
capacities of individual weed plants after cuttings, thus a probably important mechanism for
the impact of PFCs on weeds that is not frequently studied. It is based on different greenhouse
experiments realized in 2007 and 2008 in Dijon. Chapter C.IV deals with the impact of seed
predation on weed population dynamics in perennial forage crops. It is based on a short
literature review and data from field experiments realized in 2007 and 2008. These two
mechanisms are less well known than other mechanisms linked to soil tillage and competition,
which are more important and therefore better studied in annual crops.
The following part B will give an short overview of the different methods used for these four
research approaches. Part C contains the results, presented as scientific articles or manuscripts.
A final part D (general discussion) compares the different findings of the four empirical
chapters and discusses general implications, advantages and shortcomings of the different
methods and possible applications.
37