Effects of Litter Cover on Runoff-Sediment and Allelochemical Transport in a Taxus cuspidata Forest

Allelochemical transport is considered a critical topic for understanding its behavior and ecological effects in soil. Previous studies have mostly been conducted under controlled laboratory conditions, failing to capture the complexity of natural field settings. The litter of Taxus cuspidata is rich in allelochemicals, which are released during rainfall and transported to the surrounding environment. However, field research on the rainfall-driven release and transport of allelochemicals in litter is still insufficient. In this study, we investigated the transport of ten allelochemicals from Taxus cuspidata under simulated high-intensity rainfall, evaluated litter’s effect on runoff and soil sediment, and quantified allelochemical concentration. The results showed that after 90 min of simulated rainfall, concentrations of the ten allelochemicals were higher in litter-covered plots than in bare plots. Taxane allelochemicals had higher concentrations than phenolic acid allelochemicals in both treatments. Allelochemical concentration in different soil layers also increases significantly in litter-covered plots after rainfall (p < 0.05). These findings clarify the regulatory role of litter cover in the transport and accumulation of soil allelochemicals. This work provides a new perspective for exploring the environmental behavior of allelochemicals in forest ecosystems, and offers scientific guidance for understory management and allelochemical regulation in artificial Taxus forest plantations.