Diverse plant communities are known to increase soil carbon (C) levels compared to monocultures, but an incomplete understanding of the underlying mechanisms of this phenomenon limits the development of strategies for optimizing soil C sequestration. We hypothesized that the identity of neighboring plants influences the amounts of C that a plant inputs into the soil, the resultant formation of soil pore architecture, and the fate of the plant's C inputs. To test this hypothesis, we combined ¹³CO₂ plant pulse labeling with X-ray computed micro-tomography (μCT) in assessing plant-assimilated C from three species common to North American prairie: switchgrass, big bluestem, and wild bergamot. The plants were grown in a greenhouse in monoculture and in all-pair combinations. The ¹³C labeling was conducted so as to ensure that only one member of each pair has received ¹³C. The results demonstrated that greater belowground C exchange among neighboring plants enhanced inputs of plant-assimilated C into soil, suggesting that the involvement of plant community members in belowground C transfer, rather than community's diversity per se, drives rapid soil C accrual. Moreover, the magnitudes of C losses as well as properties of soil pore architecture also depend not only on the identity of the C source plant itself but also on the identities of its neighbors. These findings propose belowground interspecific C transfer as a previously overlooked mechanism for enriching and stabilizing soil C and suggest genomic and management potentials for selecting species that participate in intensive interspecific assimilate exchange in order to promote rapid and stable soil C gains.

与单一栽培相比，不同的植物群落可提高土壤碳（C）水平，但是对这种现象的潜在机制的不完全了解限制了优化土壤固碳的策略的发展。我们假设相邻植物的身份会影响植物向土壤中输入的碳量，土壤孔隙结构的最终形成以及植物碳输入的结局。为了验证这一假设，我们将^13种CO ₂植物脉冲标记与X射线计算机断层扫描（μCT）结合使用，以评估北美大草原常见的三种物种的植物同化C：柳枝,、大蓝茎和野生佛手柑。这些植物在温室中以单一栽培和全对组合的方式生长。这^进行13 C标记，以确保每对中只有一个成员收到^{13 C}C.结果表明，相邻植物之间更大程度的地下C交换增加了植物同化C向土壤的输入，这表明植物群落成员参与地下C转移而不是群落本身的多样性，推动了土壤C的快速累积。此外，碳损失的大小以及土壤孔隙结构的特性不仅取决于碳源植物本身的身份，还取决于其邻国的身份。这些发现提出地下种间C的转移是一种先前被忽视的富集和稳定土壤C的机制，并提出了基因组和管理潜力，以选择参与密集种间同化交换的物种，以促进土壤C的快速稳定获得。