Work

Estimating soil organic carbon deficits at the continental scale using legacy-data-driven dynamic baseline and attainable projections

Year: 2025

Type: article

Abstract: Soil organic carbon (SOC) stocks vary temporally, across land use, climate, and soil type, making it challenging to model current stocks (SOCcs). The attainable steady-state stock (SOCat), the practically achievable under optimal soil, climate, and management conditions, remains dynamic because soil-loss processes continually modify the biophysical limits on maximum storage, causing SOCat to shift over time. Robust methods are required to integrate temporal dynamics, model and extrapolate SOCcs and SOCat, and quantify current deficits (SOCdef), the unrealized sequestration capacity. We used legacy SOC observations along with time-adjustment and data-driven modeling to generate spatially explicit projections of 2024 SOCcs. We estimated SOCat by selecting the maximum SOC value from a spatially constrained similarity matrix of projected SOCcs, then used both reference layers to derive location-specific SOCdef. The resulting maps revealed extensive heterogeneity among the land use types and across regions. Mean SOCdef of 3.46 kg m⁻² was noted for all croplands in continental United States. Larger deficits clustered on soil orders of Mollisols and Alfisols in the Midwest region, but were lower than anticipated, alluding to depleted SOCcs and SOCat. Degraded grasslands showed similarly reduced SOCat, underscoring the need to recalibrate sequestration targets to current lower steady states. The results underscore the framework’s novelty as it effectively integrates temporal dynamics of soil carbon stocks and converts soil-carbon storage processes into actionable, farm-level sequestration targets. By generating empirically derived, region-specific SOCcs–SOCat–SOCdef benchmarks, the framework offers precise reference points that align management incentives, climate-smart policies, and site-specific restoration strategies.

Source: Geoderma

DOI: 10.1016/j.geoderma.2025.117515

Authors: Anil C. Somenahally, Laxman Bokati, Saurav Kumar

Institutions: Texas A&M University, Arizona State University

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Climate action, Life on land, Zero hunger

Open Access status: gold

Estimated APC paid: $3,320