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Beryllium-7 (Be) (T = 53.3 days) is a cosmogenic radionuclide produced by natural processes in the upper atmosphere. Upon formation, Be becomes associated with aerosols and its delivery to the Earth’s surface is largely via wet deposition whereupon Be is rapidly absorbed to soil particles. The cohesive behaviour of Be in soils, coupled with its short half-life, has underpinned its application as a tracer of soil redistribution across rainfall events or wet seasons. The premise for the use of Be as a soil redistribution tracer is introduced in this chapter.

A Be-based soil redistribution budget is based on several key datasets (Table ) which have strict rules on collection locations and timings, depending on the time period of application. Overall, the methodological approach follows the principles of other FRN techniques (e.g. the Cs approach) but with necessary differences linked to the short half-life of Be and its delivery dynamics. The difference in delivery dynamics also provides the added advantage of opportunity for assumptions underpinning the approach to be tested in field and by laboratory experimentation (Taylor et al. in J Soils Sediments 14:1886–1893, ). As summarized in Table 2.1, some datasets are mandatory to convert measurement of Be inventory into soil redistribution amounts. Other datasets are advised under some circumstances to assist with data interpretation and improve the quality of soil redistribution estimates. Fundamental considerations for the collection of all these datasets are outlined in the following section.

Gamma-ray spectrometry is the only ‘routine’ method for measuring the natural cosmogenic radionuclide Be. Activity concentrations (Bq kg) of Be are determined by analysing the 477.6 keV gamma energy emitted by the first excited state of Li (branching ratio 10.44%) (DDEP in RecommendedData, ) as it achieves the ground state. A typical gamma-spectrometric system consists of a semiconductor crystal detector, liquid nitrogen or mechanical cooling system, preamplifier, detector bias supply, linear amplifier, analogue-to-digital converter (ADC), multi-channel analyser (MCA) of the spectrum, and output data devices (ANSI in Calibration and use of germanium spectrometers for measurement of gamma-ray emission rates of radionuclides, IEEE, Inc, New York, ).

The Profile Distribution Model (PDM) is described in detail by Walling and He (J Environ. Qual 28:611–622, ) and Blake et al. (Geomorphology 104:105–116, ). Here, alongside an overview of the basic components, we provide step-by-step guidance to its implementation and simple encoding within Microsoft Excel.

The short-term perspective on soil redistribution in the landscape offered by Be is essential to policy makers with responsibility for developing efficient land management strategies to support food and water security. Soil conservation is vital for enhancement of food production on hillslopes of agroecosystems. Mobilisation of eroded soil and transfer downstream leads to siltation of river channels, lakes and reservoirs, which presents a credible threat to river basin ecosystem service provision and water security. In addition, energy security is threatened by siltation behind hydropower dams. The short-term perspective of this cosmogenic radioisotopic tool means it can provide relatively rapid assessment of very recent changes in practice. Because of its agro-environmental behaviour, this short-lived radioisotope a reliable natural isotopic tracer to assess the effectiveness of recent soil conservation strategies (Mabit et al. in Journal of Environmental Radioactivity, 99(12), 1799–1807, 2008; Taylor et al. in Water Resour Res 32:467–476, ).