Spatial and Temporal variability of fingerprint signatures for sediment source apportionment: implications for technique refinement

Sediment source fingerprinting using a variety of soil tracers has been widely adopted for obtaining reliable sediment source information, which enables efficient catchment soil conservation and sediment management campaigns. But increasing challenges are rising towards the implementation of this technique against the context of complex landscape configurations and diverse human practices. Recent studies have examined and confirmed the within-source and temporal variability of tracer signatures, herein highlighting the “non-conservative” nature of traditional well-recognized tracers. In China, the landscape fragmentation under the household-base land use system, especially in hilly and mountainous regions, has exaggerate this issue. For example, the complex spatial configuration of mosaic land use patches and dynamic inter-season cropping transitions may significantly complicate soil imprinting processes, leading to highly variability of tracer signatures in a single source group even across a relatively small spatial scale, as well as the season changes of tracer signature for a given sampling unit. In response to this potential uncertainty, improvement of sampling strategies (e.g., increase sample number by enhance sample representativeness, repeated sampling to cover different cropping season) could be an potential option for technique refinement.