Abstract
Organic amendment (OA) additions may profoundly regulate the turnover behaviours of soil organic carbon (SOC). Explicit understanding of such role of OA is crucial for accurately assessing the potential of carbon sequestration in agricultural soils. To explore the effects of OA additions on the detailed SOC stabilization and destabilization processes, we collected SOC measurements from 29 trials with experimental duration ranging from 14 to 85 years across the globe. Using these datasets, we constrained a soil carbon model to analyse SOC turnover and built-up processes as impacted by OA additions. We found that OA generally decreases microbial carbon use efficiency (CUE) and the fraction of inert SOC that is resistant to decomposition (finert), but has divergent effects on the decay rate of humic SOC (khum). Across the sites, there was great variability in the effects of OA on CUE, khum, and finert, which can be largely explained by local soil and climate conditions and the quantity and quality of OA. Long-term simulations suggested that, without considering the effects of OA on CUE, khum, and finert, the effectiveness of OA additions for carbon sequestration could be largely overestimated. Our results suggest that the strong site-specific regulations of OA on SOC dynamics as demonstrated in this study must be properly considered and better constrained by observational data when assessing SOC sequestration in agricultural soils under the management of OA additions.
Highlights
Agricultural soils are on the frontline of sequestering carbon to mitigate climate change and maintain soil fertility
The effectiveness of Organic amendment (OA) for carbon sequestration depends on the fate of OA itself, and on how OA affects soil organic carbon (SOC) stability. Both processes are highly variable depending on local soil and climate conditions
We focused on +OA treatments in the trials in order to assess the consequence of OA additions on soil C sequestration, but using optimized parameters under both +OA and −OA treatments
Summary
Agricultural soils are on the frontline of sequestering carbon to mitigate climate change and maintain soil fertility. The international initiative “4 per 1000” targets a yearly 4‰ increase of soil organic carbon (SOC) in global agricultural soils to ensure soil fertility and mitigate climate change [1,2]. To meet this target, increasing efforts have been made to identify suitable management practices that benefit SOC sequestration. The effectiveness of OA for carbon sequestration depends on the fate of OA itself, and on how OA affects SOC stability Both processes are highly variable depending on local soil and climate conditions. Elucidating the effects of OA management on SOC turnover and stabilization processes is of great importance for evaluating the feasibility of the “4 per 1000” goal
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
