De la plante à la communauté et vice et versa : stratégies et connaissances pour concevoir des prairies multi-espèces

From plants to communities and vice versa: strategies and knowledge for designing multi-species grasslands

In France, more and more grasslands are being sown with species mixtures. These mixtures meet the demand of farmers who want to be able to sow more sustainable and productive grasslands with low inputs and a better nutritional balance for animals than pure crops. Offering such mixtures is not a matter of course in a socio-technical system inherited from the forage revolution, which is still based on the model of monoculture and input-based management. Composing, selecting, producing and managing forage mixtures still requires overcoming a number of cognitive, technical and organisational barriers. In particular, it is necessary to move beyond the insurance strategy of sowing several species and varieties to ensure that at least one of them survives, in order to truly capitalise on the synergies between species. The objective for research is to produce scientific knowledge that will enable us to take advantage of the complementarities between plants so that a sown meadow produces the diversity of ecosystem services expected in a given environment. Since the authorisation of the commercialisation of mixtures in 2004, two approaches have worked independently towards this objective. The first has its origins in community ecology and the study of permanent grasslands and has resulted in the Capflor® tool. The second approach stems from genetic selection methodology and ecophysiology applied to major forage species. After presenting these two approaches, their strengths, weaknesses, threats and opportunities, we will propose avenues for further work to exploit their complementarity in order to optimise a range of mixtures according to uses and environmental conditions.