Cropping systems based on carefully designed species mixtures reveal many potential
advantages in terms of enhancing crop productivity, reducing pest and diseases,
and enhancing ecological services. Associating cereals and legume production either
through intercropping or rotations might be a relevant strategy of producing both type
of culture, while benefiting from combined nitrogen fixed by the legume through its
symbiotic association with nitrogen-fixing bacteria, and from a better use of P and water
through mycorrhizal associations. These practices also participate to the diversification
of agricultural productions, enabling to secure the regularity of income returns across
the seasonal and climatic uncertainties. In this context, we designed a field experiment
aiming to estimate the 2 years impact of these practices on wheat yield and on soil
microbial activities as estimated through Substrate Induced Respiration method and
mycorrhizal soil infectivity (MSI) measurement. It is expected that understanding soil
microbial functionalities in response to these agricultural practices might allows to target
the best type of combination, in regard to crop productivity. We found that the tested
cropping systems largely impacted soil microbial functionalities and MSI. Intercropping
gave better results in terms of crop productivity than the rotation practice after two
cropping seasons. Benefits resulting from intercrop should be highly linked with changes
recorded on soil microbial functionalities.

Keywords: arbuscular mycorrhizal fungi, cropping systems, nutrient uptake efficiency, microbial soil functions,
Mediterranean region