Estimating short-term soil erosion rates after single and multiple rainfall events by modelling the vertical distribution of cosmogenic 7Be in soils

• A process-based model of 7Be in soil is presented.
• A mathematical simulation study of the proposed model is given.
• Erosion rate quantification done for twelve short-term events
• Current 7Be technique modified from single to multiple rainfall situations

The 7Be method is a promising tool for estimating soil erosion rates at time scales of days to months. However, so far its applicability is limited to steady state concentrations of the tracer. In this paper a diffusion-sorption model is presented, which takes into account atmospheric input rates, transport down the soil column and radioactive decay of 7Be. It allows simulation of the non-steady-state 7Be inventories and depth distributions in soil and their modification by discrete erosion events as well as by tillage. This model is used to quantify erosion rates for 12 individual heavy rainfall events over a period of two years at an agricultural study site in Germany. Comparisons of soil collected at the bottom of our study site with predictions made using our proposed radioberyllium technique generally show good to excellent agreement even for multiple erosion events.