Future Litter Decomposition Research Should Prioritize the Litter to Soil Flux.

In the study of carbon (C) cycling, litter decomposition is a key process through which C transfers from plants to soil, thereby influencing soil fertility, C sequestration, and ecosystem functions. However, current research on litter decomposition experiments and modeling mainly focuses on litter mass loss, with relatively few studies focusing on the C flux from plant litter to soil (Cinput). In fact, the Cinput process during litter decomposition is an important factor influencing soil C cycling and is crucial for predicting soil organic C (SOC) stocks and fluxes. Previous litter decomposition experiment data can be used for model data assimilation and uncertainty testing, facilitating model-data integration. Future research should prioritize quantifying the pathways, fluxes, and mechanisms controlling litter-derived C transfer into soils. This requires coordinated efforts among observational studies, experiments, and ecosystem modeling, where empirical approaches identify key processes and models provide frameworks for evaluating their representation and implications for soil C dynamics. In summary, improving the quantification and representation of Cinput is critical for advancing our understanding and projections of terrestrial C cycling and reducing uncertainties in ecosystem C feedbacks under future climate change.