In order to achieve climate neutrality by 2050 (European Green Deal ambition) we will need the use of maximum potential of soils for mitigation and adaptation strategies (Montanarella and Panagos, 2021).

Since the 4 per mille initiative was launched, a diversity of cropping systems and management practices have been evaluated for their contribution to carbon (C) sequestration. Because soil organic matter is a major component of soil fertility, soil quality and resilience, increasing SOC storage would also contribute to climate change mitigation and other ecosystem services (reducing erosion, biodiversity, water storage).

The projects, MaxRoot-C and MixRoot-C are complementary to each other and are developed to ensure maximum synergies and maximum complementarity. The two projects focus on different systems, one on conventional, pure cultures and one on mixed cultures. Both systems are relevant in European agriculture since one is the dominating system (pure cultures) and one is an upcoming niche system (mixed system). In both systems large knowledge gaps exist on aspects of root C input to the soil and their role for soil C.

In pure culture systems the main question is how different genotypes and cover crop types can be used and developed by breeders that optimize and maximize root C input.

In mixed systems it is the question how synergistic effects can be stimulated by combining different crop types.