6: Can plant diversification promote a more efficient soil functioning and nutrient cycling?

In natural or semi-natural ecosystems, it has been demonstrated that plant diversity enhances ecosystem performance via complementary and sampling effects. While the influence of species richness on biomass production was initially emphasised, it has since been demonstrated that genetic diversity within species is also influential, improving the provision of ecosystem services beyond merely biomass production. Complementarity and sampling effects require functional differences between plant species and genotypes, involving multiple interactions between plants, soils, and soil organisms. These effects have been observed in natural ecosystems and must be implemented more widely in agroecosystems to improve agricultural sustainability, while maintaining productivity by using the natural capacity of soil ecosystems to supply plants in available nutrients. The aim of the workshop is to explore these effects and the underlying mechanisms. These mechanisms include: (1) plant complementarity in the use of soil resources (e.g. mineral nutrients and water); (2) complementarity in interactions with symbionts; (3) interactions with soil herbivores and pathogens; (4) synchronisation of plant demand for mineral nutrients with provision by soil microbial communities; (5) nitrogen fixation and phosphorus solubilisation. The symposium will address studies on these fundamental mechanisms and how to harness them in agroecosystems. We will for example examine how other practices (e.g. fertilisation) influence the outcome of these mechanisms and how selection of new varieties can favour them.