Kravchenko, A. N., H. Zheng, Y. Kuzyakov, G. P. Robertson, and A. K. Guber. 2021. Belowground interplant carbon transfer promotes soil carbon gains in diverse plant communities. Soil Biology and Biochemistry 159:108297.
Diverse plant communities are known to increase soil carbon © 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.
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