Subsurface flow and phosphorus dynamics in beech forest hillslopes during sprinkling experiments: how fast is phosphorus replenished?

Abstract. The phosphorus (P) concentration of soil solution is key importance for plant nutrition. During large rainfall events, the P altered by lateral and vertical subsurface storm flow (SSF) that facilitates mobilization, redistribution within profile potential export from ecosystem. These processes are not well studied under field conditions. Important factors replenishment concentrations in solutions rate (by biotic abiotic processes) buffering capacity soils. Lab experiments have shown times can vary between minutes months. question remains how SSF natural We present results large-scale sprinkling simulating 150 mm throughfall at 200 m2 plots on hillslopes three beech forests Germany. aimed quantifying associated forest floor, mineral saprolite during spring summer. sites differed mainly terms depth, skeleton content stock (between 189 624 g/m2 top 1 m depth). Vertical was least 2 orders magnitude larger than same depth. consisted pre-event water replaced water. Higher first to h after onset indicated nutrient flushing, but were nearly constant thereafter most experiment despite a strong increase SSF. This suggests all replenished fast or organic sources. If chemostatic transport conditions would dominate SSF, annual losses boundary plot could be approximated knowing average fluxes A rough estimation loss based this simplified assumption one our with longer data resulted an 3.16 mg/m2/a. similar estimates previous study site using bi-weekly groundwater samples. Our order as input dry wet deposition weathering. Despite fact ecosystem seem small, translocation floor might high relevance low stocks where dominant source nutrition trees.