Soil carbon sequestration benefits of active versus natural restoration vary with initial carbon content and soil layer

Abstract

Reducing terrestrial carbon emissions is a big challenge for human societies. Ecosystem restoration is predominant to reverse land degradation and carbon loss. Though active restoration of croplands is assumed to increase carbon sequestration more than natural regeneration, it still lacks the robust paired comparisons between them. Here we performed a large-scale paired comparison of active versus natural restoration effects on soil carbon sequestration across China. We found that two restoration strategies consistently enhanced soil carbon relative to croplands, however, the benefits of active restoration versus natural regeneration were highly context-dependent. Active restoration only sequestered more carbon in carbon-poor soils but less carbon in carbon-rich soils than natural regeneration. Moreover, active restoration fixed greater carbon in topsoil but less carbon in subsoil. Overall, these findings highlight landscape context-dependent application of active restoration and natural regeneration, further guiding the efficient management of limited resources to maximize the restoration benefits of carbon sequestration.