Spatial prediction of the concentration of selenium (Se) in grain across part of Amhara Region, Ethiopia

Gashu, D and Lark, R M and Milne, A E and Amede, T and Bailey, E H and Chagumaira, C and Dunham, S J and Gameda, S and Kumssa, D B and Mossa, A W and Walsh, M G and Wilson, L and Young, S D and Ander, E L and Broadley, M R and Joy, E J M and McGrath, S P (2020) Spatial prediction of the concentration of selenium (Se) in grain across part of Amhara Region, Ethiopia. Science of The Total Environment (TSI), 733. pp. 1-16. ISSN 0048-9697

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Grain and soilwere sampled across a large part of Amhara, Ethiopia in a study motivated by prior evidence of selenium (Se) deficiency in the Region's population. The grain samples (teff, Eragrostis tef, and wheat, Triticum aestivum) were analysed for concentration of Se and the soils were analysed for various properties, including Se concentration measured in different extractants. Predictive models for concentration of Se in the respective grainswere developed, and the predicted values, alongwith observed concentrations in the two grainswere represented by a multivariate linear mixed model in which selected covariates, derived from remote sensor observations and a digital elevation model, were included as fixed effects. In all modelling steps the selection of predictors was done using false discovery rate control, to avoid over-fitting, and using an α-investment procedure to maximize the statistical power to detect significant relationships by ordering the tests in a sequence based on scientific understanding of the underlying processes likely to control Se concentration in grain. Crossvalidation indicated that uncertainties in the empirical best linear unbiased predictions of the Se concentration in both grains were well-characterized by the prediction error variances obtained from the model. The predictions were displayed as maps, and their uncertainty was characterized by computing the probability that the true concentration of Se in grain would be such that a standard serving would not provide the recommended daily allowance of Se. The spatial variation of grain Se was substantial, concentrations in wheat and teff differed but showed the same broad spatial pattern. Such information could be used to target effective interventions to address Se deficiency, and the general procedure used for mapping could be applied to other micronutrients and crops in similar settings.

Item Type: Article
Divisions: Research Program : East & Southern Africa
Uncontrolled Keywords: Selenium, Micronutrients, Hidden hunger, Teff, Wheat, Geostatistics
Subjects: Others > GIS Techniques/Remote Sensing
Others > Plant Nutrition
Others > Wheat
Depositing User: Mr Arun S
Date Deposited: 09 Aug 2020 14:21
Last Modified: 09 Aug 2020 14:21
Official URL:
Funders: Biotechnology and Biological Sciences Research Council (BBSRC), Global Challenges Research Fund (GCRF), Bill & Melinda Gates Foundation (BMGF)
Acknowledgement: This work was supported by ‘GeoNutrition’ projects, funded by Biotechnology and Biological Sciences Research Council (BBSRC) / Global Challenges Research Fund (GCRF) [BB/P023126/1] (project lead, SPM); and the Bill &Melinda Gates Foundation (BMGF) [INV-009129] (project lead, MRB). The funders were not involved in the study design, the collection, management, analysis, and interpretation of data, thewriting of the report or the decision to submit the report for publication. The boundaries, denominations, and any other information shown on the maps in Figs. 8–13 do not imply any judgment about the legal status of any territory, or constitute any official endorsement or acceptance of any boundaries, on the part of any Government. The road network data used in the sample planning were copyrighted OpenStreetMap contributors and available from https:// The CHELSA project is acknowledged for making the downscaled climate data available from https:// The authors gratefully acknowledge the contribution made to this research by the field sampling team of the Amhara National Regional Bureau of Agriculture. Debebe Hailu and Aregash Beshire also contributed to sample preparation. ELA's contribution is publishedwith the permission of the Executive Director of the British Geological Survey (NERC).
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