Designing species mixtures
The current agricultural model is based mainly on the use of fertilizers, phytosanitary products and irrigation, which has increased and maintained high agricultural production1. However, this agricultural model has shown its limitations in terms of sustainability and resilience. It offers farmers little choice in how they run their farms, but also negatively impacts the environment. Crop diversification through species mixtures is considered an alternative to the use of inputs2. Species mixtures increase biological interactions in the agroecosystem, modify the physical/chemical/bio states of the environment, which impacts soil fertility, and could reduce the use of synthetic inputs by regulating pests3. However, this approach is difficult to implement for various reasons (lack of knowledge on species mixtures and their management, locking in value chains, lack of political will, etc.)4.
The challenge today is to produce specific knowledge that will facilitate the design of new systems beyond the "classic" mixtures that already exist. In particular, it should be possible to identify the (ecosystem) services potentially rendered according to the different possibilities of species mixtures (combination of species in given environments). Plant traits play an important role in the compatibility of species mixtures. The identification of "compatible" traits to design successful mixtures is necessary, especially since the value of these traits varies when moving from a pure crop to a mixture of crops. It is in this context that this internship topic will be conducted in order to identify reliable functional indicators that allow to characterize mixtures and to identify assembly rules.
References: (1) Tilman, 2002 (2) Malézieux et al. 2009; M. Duru et al. 2015 (3) Malézieux et al. 2009; M. Duru et al. 2015; Beillouin et al. 2019 (4) Meynard, 2012; Caron et al. 2014
Project leaders: Safia Médiène and her PhD student Malick Ouattara, from the Agronomy
Graduate school of the Université Paris-Saclay concerned: Biosphera