Since the 1980s, tremendous effort has been made on root dynamics, including root growth, turnover, and decomposition, which determine the contribution of root inputs to soil C. However, conventional studies typically focus on either root-derived C inputs (i.e., root growth and death) or C outputs (root decomposition), overlooking or coarsely estimating their integrated effects. This impedes our ability to accurately assess and predict the role of roots in soil C accumulation.

Prof. KOU Liang’s team at the Institute of Geographic Sciences and Natural Resources Research (IGSNRR) of the Chinese Academy of Sciences (CAS) and their collaborators propose a novel paradigm of root iterative effects to investigate the long-term and integrated effects of roots with fast turnover and slow decomposition on soil C dynamics.

This study was published in Trends in Plant Science.

The novel paradigm of root iterative effects is defined by multi-generational root production and turnover (i.e., successive cohorts of root litter inputs) coupled with multi-stage root decomposition (i.e., co-occurrence of litter at contrasting decomposition stages).

This paradigm establishes an unprecedented link between the entire root dynamic process and belowground C storage, providing a comprehensive understanding of the long-term contribution of iterative root dynamics to soil C pools.

The researchers present several heuristic scenarios that differentiate root iterative effects on carbon cycling within branching root systems, across steady and non-steady state ecosystems, under natural and anthropogenic disturbances, and shaped by intra- and inter-generational interactions among root processes.

“We develop the theories of root structure-function relationships and advances our mechanistic understanding of soil C cycling. It also hope to provide a novel insights into ecosystem responses to global changes”, said Prof. KOU.

Reference:

Kou Liang#*, Ma Ning#, Grégoire T. Freschet, M. Luke McCormack, Shenggong Li. 2025. Iterative effects: a new paradigm for root dynamics. Trends in Plant Science, doi: 10.1016/j.tplants.2025.05.018.

The paradigm of root iterative effects and the heterogeneous nature of root dynamics within branching root systems. (Image by KOU Liang)