Stabilisation of carbonates in soils

AXIS 2: Coupling of biogeochemical cycles in a context of global change

Stabilisation of carbonates in soils

Soils play an essential role in the global carbon cycle. Inorganic carbon in soil (ICS) is thought to have much longer renewal rates (more than 1000 years) than organic carbon (OC, around 50 years). However, the destabilisation of SIC can be induced by agricultural practices, particularly nitrogen fertilisation, which is a major concern in the context of mitigating climate change. Thanks to the study proposed here, we hope to (1) untangle, by combining fieldwork and experiments under controlled conditions, the processes involved in the degradation of different types of soil carbonates and (2) estimate their contribution to the carbon fluxes observed on site at the scale of two 10-metre-deep pits located on an agroforestry farm and an irrigated crop site in a subtropical region of southern India (ANR NutriLIFT Project). These two sites are part of the Indian experimental catchment areas TROPical CatchmentS National Multiscale Observation Service (https://mtropics.obs-mip.fr/), Berambadi catchment area.