Promoting the use of isotopic techniques to combat soil erosion: An overview of the key role played by the SWMCN Subprogramme of the Joint FAO/IAEA Division over the last 20 years

Abstract

The International Atomic Energy Agency (IAEA), through the Joint Division with the Food and Agriculture Organization (FAO) of the United Nations, assists its Member States in applying nuclear techniques to alleviate challenges in food safety, food security and sustainable agricultural development. The Soil and Water Management & Crop Nutrition (SWMCN) Subprogramme, within the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, has made significant contributions to the development of isotopic techniques for the assessment of soil degradation and the development of efficient soil and land conservation approaches. These techniques include fallout radionuclides such as 137 Cs, 210 Pb ex , 7 Be, and 239+240 Pu as well as 13 C stable isotope and compound-specific stable isotope analyses. These methodologies were developed and/or refined through the work of researchers from developed and developing countries who were selected to work within the frame of IAEA's Coordinated Research Projects (CRPs). Internal research activities implemented in the Joint FAO/IAEA's SWMCN Laboratory in Seibersdorf supported the work accomplished in the CRPs. The methodologies thus developed have been subsequently disseminated to developing countries by IAEA's Technical Cooperation Programme to assist Member States to adopt climate-smart agriculture and reduce soil degradation that poses a threat to food security and the environment. This review paper provides an overview of the activities conducted in the frame of CRPs for combating soil erosion over the last 20 years and highlights the major achievements. Examples of the success and the impact obtained in Morocco, Madagascar, and Vietnam in using these isotopic techniques are presented.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Sediment source fingerprinting: benchmarking recent outputs, remaining challenges and emerging themes

“…To achieve this goal, researchers have developed approaches to trace sediment sources based upon source soil and sediment compound-specific stable isotope (CSSIs) signatures (Gibbs 2008 ). To date, the CSSI approach has been limited to the use of fatty acids and alkane carbon isotopic composition to identify the contribution of fields under specific crop rotations (Blake et al 2012 ; Mabit et al 2018a , b ), as well as sediment sources in forest plantations of Chile (Bravo-Linares et al 2018 ) or mixed land use catchments (Upadhayay et al 2018b ). Integration of the δ 2 H values of long-chain alkanes and fatty acids in tracer sets has shown great potential for extracting additional information on sediment origin related to dominant vegetation types (Gao et al 2011 ) and elevation gradients (Feakins et al 2018 ).…”

“…Recently, land cover–dependent differences in the δ 13 C isotopic values of specific organic compounds (i.e. soil fatty acids, n -alkenes) have been used to estimate source contributions from different land use types without accounting for the effect of isotopic content on un-mixing model results (Gibbs 2008 ; Blake et al 2012 ; Hancock and Revill 2013 ; Alewell et al 2016 ; Brandt et al 2016 , 2018 ; Bravo-Linares et al 2018 ; Mabit et al 2018a , b ). Here, the concentration-independent approach assumes an identical isotopic tracer content for all sources.…”

Dating reservoir deposits to assess the recently changing sediment yields from a medium‐sized agricultural catchment

“…137 Cs is an artificial radionuclide derived from atmospheric nuclear tests and can provide a reliable marker for the year 1963 when 137 Cs fallout was at its peak. 210 Pb is formed naturally by the radioactive decay of 226 Ra in rocks and soils, and the excess fallout of 210 Pb ( 210 Pbex) can be assumed to be essentially constant over time (Mabit, Benmansour, & Walling, 2008;Mabit et al, 2014Mabit et al, , 2018. 210 Pb ex dating is usually appropriate for deposits that have formed from continuous sedimentation over the past 100 years (Appleby, Oldfield, Thompson, & Huttunen, 1979).…”

Research into Practice—Linking Be-7 Evidence to Land Management Policy Change for Improved Food Security

“…Following the CRPs activities, several guidelines were produced by the SWMCN Subprogramme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture (e.g. IAEA 2014; Mabit et al 2018). Impact on policy has been further extended worldwide to several IAEA Member States and FAO Member Countries by methodology transfer and capacity-building activities within IAEA national and/or regional technical cooperation projects (e.g.…”