Nitrogen addition-driven soil carbon stability depends on the fractions of particulate and mineral-associated organic carbon

Le résumé fourni par la source

Abstract Nitrogen (N) deposition greatly affects soil carbon (C) fractions, triggering changes in soil organic carbon (SOC) persistence and functionality. However, the responses of soil C fractions to N deposition remain unclear on a global scale. Here, we conducted a meta-analysis of 69 publications and explored the response of C fractions (particulate organic carbon, POC; mineral-associated organic carbon, MOC) to N addition. We found that N addition significantly increases the POC and MOC pool, yet the large rise in the fraction of POC (fPOC) and the decline in the fraction of MOC (fMOC) were observed, suggesting that N addition enhances soil C pool but decreases soil C stability globally. Moreover, the response ratios of POC and MOC were positively correlated with the duration of N addition. For soil C sequestration, POC was the most important predictor under short-term N addition, while the MOC jointly contribute to the C accumulation after long-term N addition. Overall, our study provides solid evidence that N addition would reduce the soil C stability mainly depending on the POC change and proposes a novel approach to predict the soil C-climate feedback for Earth System Models.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.