With the wide application of 7Be (Beryllium-7) in soil erosion investigations, retention and interception of 7Be by vegetation plays an important role in documenting soil 7Be redistribution, with a large impact on the interpretation of 7Be measurements. However, the dynamic and temporal changes in plants and the relationship with soil 7Be concentration remain unclear, and the significance of dead plants in 7Be interception is under-researched.
The samples of single plants (6 different species), compositive plants (including living and dead plants), along with soil reference on the Loess Plateau were collected individually to analyze the variations of 7Be concentration during the growth period from 2010 to 2012.
The accumulation of 7Be per mass is significantly higher in leaves than stems. The 7Be activity per mass and per area in living plants with seasonal trends ranged from 173.9 to 703.1 Bq kg–1 and 21.5 to 190.1 Bq m–2, respectively, and in dead plants ranged from 381.8 to 964.5 Bq kg–1 and 30.4 to 285.7 Bq m–2. Precipitation accounted for the largest contribution to the accumulation of 7Be in plants, followed by plant growth, species and parts. Plants accounted for 7Be interception on slope up to 66% (living plants accounted for 7% ~ 31% and dead plants accounted for 6% ~ 44%). The interception of living plants is low at first, then increases with the accumulation of rainfall and biomass together.
Our results highlight that 7Be in plants (especially for the dead plants) is of great significance for 7Be in soil on the slope, and is controlled by precipitation, growth status and plant characteristics. The reference information obtained in this work will contribute to improving the accuracy of 7Be tracing technology, and broadening its scope.