Regenerative management has potential to increase soil organic carbon (SOC), which will be crucial for mitigating climate change and improving soil health. Distinct fractions of SOC, particulate organic carbon (POC) and mineral-associated organic carbon (MAOC), have been posited as having contrasting responses to regenerative management. The POC response has been proposed as a leading indicator of total SOC response, whereas MAOC response has been seen as eventually limiting SOC response due to its saturation behavior. We explored these and linked expectations of SOC, POC and MAOC response by leveraging multiple datasets of regenerative management with cover crops or perennial crops as contrasted with conventional management (n = 42 sites). Across sites, POC as a percentage of SOC was on average 19%. Regenerative management increased both POC and MAOC but increases in POC were smaller and narrower (0.78 ± 0.26 g C kg soil^-1) than increases in MAOC (1.41 ± 0.80 g C kg soil^-1). Changes in POC were only weakly correlated with changes in SOC (p < 0.001 but R² = 0.11), revealing that absolute changes in POC at any timepoint should not be taken as indicative of total SOC responses. The MAOC response made up the majority of SOC response at 58% of sites. Changes in POC and MAOC with regenerative management were also not related (p = 0.72), indicating that comprehensive assessment of POC and MAOC is needed to understand SOC accumulation under regenerative management. Increases in POC were explained by annual average of increase in root C inputs with regenerative management, suggesting a limited ability for the current portfolio of regenerative management practices to increase POC, even when implemented over decadal timescales. In contrast, increases in MAOC were partially explained by cumulative-for-the-trial increases in root C inputs and were not clearly constrained by silt + clay-estimated saturation deficit. Our results indicate that the increase of MAOC storage in agricultural soils is not limited by saturation but rather by the extent to which root C inputs can be augmented, and that increasing POC storage will require novel practices to overcome current limitations on POC accumulation.

再生管理有可能增加土壤有机碳（SOC），这对于缓解气候变化和改善土壤健康至关重要。SOC、颗粒有机碳（POC）和矿物相关有机碳（MAOC）的不同部分被认为对再生管理具有截然不同的反应。POC 响应被提议作为总 SOC 响应的主要指标，而 MAOC 响应由于其饱和行为而被视为最终限制 SOC 响应。我们通过利用覆盖作物或多年生作物再生管理的多个数据集，与传统管理（n = 42 个地点）相比，探索了这些问题，并将 SOC、POC 和 MAOC 响应的预期联系起来。在各个站点中，POC 占 SOC 的百分比平均为 19%。^{再生管理增加了 POC 和 MAOC，但 POC 的增加幅度（0.78 ± 0.26 g C kg 土壤-1}）比 MAOC 的增加（1.41 ± 0.80 g C kg 土壤^-1 ）更小且更窄。POC 的变化与 SOC 的变化仅有弱相关性（p < 0.001，但 R ² = 0.11），表明任何时间点 POC 的绝对变化不应被视为总 SOC 响应的指示。MAOC 响应占 58% 站点 SOC 响应的大部分。POC 和 MAOC 的变化与再生管理也不相关（p = 0.72），这表明需要对 POC 和 MAOC 进行综合评估以了解再生管理下的 SOC 积累。POC 的增加是通过再生管理根碳输入的年平均增加来解释的，这表明当前的再生管理实践组合增加 POC 的能力有限，即使在十年的时间尺度上实施也是如此。相比之下，MAOC 的增加部分是由根 C 输入的试验累积增加来解释的，并且没有明显受到粉土 + 粘土估计的饱和度赤字的限制。我们的结果表明，农业土壤中 MAOC 储存量的增加不受饱和度的限制，而是受到根部碳输入可增加的程度的限制，并且增加 POC 储存量将需要新的做法来克服目前对 POC 积累的限制。