Rhizosphere engineering for soil carbon sequestration

The rhizosphere is the central hotspot of water and nutrient uptake by plants, rhizodeposition, microbial activities, and plant-soil-microbial interactions. The plasticity of plants offers possibilities to engineer the rhizosphere to mitigate climate change. We define rhizosphere engineering as targeted manipulation of plants, soil, microorganisms, and management to shift rhizosphere processes for specific aims [e.g., carbon (C) sequestration]. The rhizosphere components can be engineered by agronomic, physical, chemical, biological, and genomicapproaches. These approaches increase plant productivity with a special focus on C inputs belowground, increase microbial necromass production, protect organic compounds and necromass by aggregation, and decrease C losses. Rhizosphere engineering focus on the accumulation and stabilization of C in the soil either directly or indirectly through: (i) raising root-derived C inputs; (ii) increasing the production of microbial biomass and necromass; and (iii) enhancing C stabilization in the soil. Rhizosphere engineering is crucial to manage rhizodeposition, microbial activities, and plant–soil–microbial interactions, and thus soil C sequestration under global change and human impacts. Finally, we outline multifunctional options for rhizosphere engineering: how to boost C sequestration, increase soil health, and mitigate global change effects.