Carbonate influences on the biogeochemical processes driving the stabilization of soil organic carbon in drylands

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Increasing temperatures and worsening drought from climate change are exacerbating soil degradation and desertification indrylands, presenting a major threat to food security. Soil organic carbon (SOC) loss is a strong driver of soil degradation anddesertification. Increasing SOC can mitigate soil degradation, but dryland SOC stocks can be minimal, and critically, most soil carbonin drylands exists as carbonate (SIC). SIC likely moderates the physical stabilization of SOC in the soil mineral matrix via pedogenicprocesses that form SIC-organo-mineral structures. Pedogenic processes may increase SOC stabilization by controlling physical accessof microorganisms to substrate, but it's unclear how they indirectly alter microbial processes and SOC decomposition/stabilization. Tothis end, SIC-SOC-STABLE aims to 1) quantify the global influence of SIC on SOC stabilization in drylands using an established dataset,and 2) validate global patterns along a local field gradient and to generate a detailed understanding of how physical stabilizationstructures, driven by carbonate pedogenesis influence the microbial processes driving SOC stabilization. Further, considering theimpacts of soil management on SOC storage in drylands is fundamental given that soil tillage may accelerate carbonate pedogenesis.It addresses the agricultural implications of IPCC recommended management practices like reduced tillage on SOC stabilization incalcareous soils, by 3) experimentally quantifying the influence of soil disturbance on carbonate pedogenesis and the fate ofmicrobially-mediated SOC storage. Finally, because reduced tillage requires greater mechanical weeding, a role which predominantlyfalls on women in rural drylands, the proposed MSCA considers gender disparity in labor when advocating best practices to increasesoil carbon. To achieve this, it 4) develops a scientifically robust training and support tool to empower and equip women for key rolesin agricultural management.