Micronutrient Bioavailability and the African Soil Information Service Steve McGrath Sustainable Agriculture Sciences
Soil – Food Chain – Humans (and animals) • Background • GeoNutrition examples • AfSIS developments • Antimicrobial resistance • Soil microbiome
A growing nutritional crisis • Malnutrition : stunting, wasting, deficiencies of essential vitamins and minerals, and obesity. • Overweight, obesity and diet-related chronic diseases such as diabetes and hypertension • More than 2 bn people lack vital micronutrients (e.g., iron, zinc, selenium, vitamin A) which affects their health and life expectancy. • 25% children <5 y today are stunted, with diminished physical and mental capacities. Undernourished mothers are having babies who will be left with life- long impairments.
Food systems and diets • Malnutrition no.1 risk factor in the global burden of disease • Food systems are not delivering healthy diets • Potential interventions • Fertiliser (agronomic biofortification) • Genetically biofortified crops • Alter diet • Dietary fortification (supplementation) • Iodised salt 1. Selenium example 2. AfSIS/iSDA developments 3. Ongoing GeoNutrition projects
1. Selenium
Increased health risks protection against: associated with low Depression, Cognition Eye disease Se status: cretinism Thyroid disorders • Heart disease • Mortality Lung cancer • • Poor immune function Asthma • • Impaired thyroid function Colon cancer • Male infertility • • Increased risk of cancer?? Prostate cancer Infertility • • Cardiovascular disorders (e.g. Keshan disease) Kashin-Beck • Animals: disease fertility, white muscle disease
Potential factors affecting Se bioavailability – assessed Jones et al, PNAS, 2017, 114, 2848 – 2853.
Predicted change in topsoil Se concentrations Predicted changes in soil Se concentrations ` Jones et al, PNAS, 2017, 114, 2848 – 2853.
Selenium supply in Malawi: soil and grain surveys Dr Allan Chilimba Prof Martin Broadley
Selenium supply in Malawi: maize-grain survey 0.325 mg kg -1 0.021 mg kg -1 Chilimba ADC, Young SD, Black CR, Rogerson KB, Ander EL, Watts M, Lammel J, Broadley MR (2011). Maize grain and soil surveys reveal suboptimal dietary selenium intake is widespread in Malawi. Scientific Reports , 1, 72.
Selenium supply in Malawi: maize-grain survey Chilimba ADC, Young SD, Black CR, Rogerson KB, Ander EL, Watts M, Lammel J, Broadley MR (2011). Maize grain and soil surveys reveal suboptimal dietary selenium intake is widespread in Malawi. Scientific Reports , 1, 72.
Soil geochemistry linked to selenium intake… Bandawe Tembo Kenani Msekeni Ngayiwona Yesaya Jere Yolamu 0.0 0.1 0.2 0 50 100 150 200 Billy Chamwaka Chifundo Chimkango Moses (a) (b) Mozyenti 0.00 0.05 0.10 0.15 0.20 0 50 100 150 200 250 Dietary Se intake (mg d -1 ) Blood plasma Se (µg L -1 ) Bandawe Tembo Kenani Msekeni Ngayiwona Yesaya Jere Yolamu 0 20 40 60 80 100 0 50 100 150 200 Billy Hurst R, Siyame E, Young SD et al. (2013) Chamwaka Hurst R, Siyame E, Young SD et al. Nat Sci Rep (2013) Chifundo Urinary Se (µg L
Soil geochemistry linked to selenium intake… …and status Bandawe Tembo Kenani Msekeni Ngayiwona Yesaya Jere Yolamu 0.0 0.1 0.2 0 50 100 150 200 Billy Chamwaka Chifundo Chimkango Moses (a) (b) Mozyenti 0.00 0.05 0.10 0.15 0.20 0 50 100 150 200 250 Dietary Se intake (mg d -1 ) Blood plasma Se (µg L -1 ) Bandawe Tembo = GeoNutrition! Kenani Msekeni Ngayiwona Yesaya Jere Yolamu 0 20 40 60 80 100 0 50 100 150 200 Billy Chamwaka Hurst R, Siyame E, Young SD et al. Nat Sci Rep (2013) Chifundo Urinary Se (µg L
Agronomic biofortification Malawi: results summary 0.6 0.5 Grain Se (mg Se kg -1 ) 0.4 0.3 0.2 0.1 0.0 0 10 20 30 Se application (g Se ha -1 ) Liquid drench y = 0.019 x + 0.061 ~0.02 mg Se kg -1 grain / g -1 Se ha -1 CAN+Se (granular) y = 0.015 x + 0.085 UK wheat – just as low/responsive to Se NPK+Se (granular) y = 0.022 x + 0.056 Chilimba ADC et al. (2012). Field Crops Research 125: 118-128
2. AfSIS/iSDA Geospatially explicit information
Africa Soil Information Service (AfSIS) africasoils.net Rothamsted led from Nov 2016-18 ICRAF, EI, ISRIC, Ethiopia, Tanzania, Ghana & Nigeria national SIS Now: iSDA Ltd – innovative Solutions for Decision Agriculture Company recently set up in UK, 2018 Supply a wide range of decision makers (governments, industry, service providers, farmers) with business relevant soil, crop, and land information services for specific use cases
Sentinel sites Randomized sampling schemes Consistent field protocol Coupling with Prevalence, Risk factors, Digital Soil spectroscopy remote sensing mapping
New dry spectral lab at Rothamsted Plant Soil High throughput MIR (Mid Infrared) analysis for a range of properties XRD (X-Ray Diffraction) pXRF (portable X-Ray Fluorescence) Dry and wet laser particle mineralogy analysis elemental analysis size analysis
Calibration of dry spectral instruments PLANT FERTILISER SOIL
Cali libration of th the XRF Plant, soil, fertiliser and organic manures Plant standards (n = 67) analysed using ICP-OES/ICP-MS and XRF: potassium- r = 0.95 phosphorus- r = 0.94 zinc- r = 0.99 0.021 0.6 0.020 5 0.019 0.018 0.017 0.5 0.016 4 0.015 XRF Concentration (%) XRF Concentration (%) XRF Concentration (%) 0.014 0.4 0.013 0.012 3 0.011 0.3 0.010 0.009 0.008 2 0.007 0.2 0.006 0.005 1 0.004 0.1 0.003 0.002 0.001 0 0 0 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 Concentration (%) Concentration (%) Concentration (%) Conc. XRF Conc. XRF Conc. XRF
AfSIS lab Arusha, Tanzania Isaac Leramo
Africa 2016 cropland area p(CP) 2016 cropland area estimate ~6.7 M km 2 (of the total 30 M km 2 , African continent) GeoSurvey - crowdsource
Predicted topsoil (0-20 cm) pH Croplands with probable lime requirement pH < 5.5 = ~447 M ha CROP & pH < 5.5 = ~85 M ha pH GeoSurvey – crowdsource MobileSurvey – sampling app Dry spectroscopy techniques
Predicted topsoil (0-20 cm) extractable Zn mg/kg Blue or light blue – critical for crop growth GeoSurvey – crowdsource MobileSurvey – sampling app Dry spectroscopy techniques
EthioSIS Courtesy of Ethiopian Ministry of Agriculture/ ATA
Courtesy of Ethiopian Ministry of Agriculture/ ATA
Courtesy of Ethiopian Ministry of Agriculture/ ATA
3. . Geo: Geospatially resolved information Geography Geochemistry Crops Climate etc Data layers: Human biomarkers Dietary intakes Ethiopia (AAU, ATA) Diet Malawi (DARS, MoH, CHSU, LUANAR) Crops Soil properties n Soil properties 3 Soil properties 2 Soil properties 1 Most cropland, 1 2 Pilot areas, mapping, linkages Mapping, linkages, intervention studies
Conclusions • Biofortification method – depends on the nutrient of interest • Micronutrient content depends on variety, soil conditions, climate • Need diagnostics, and spatially explicit recommended interventions • Collaboration
Acknowledgements Ethiopia (AAU, ATA) Malawi (DARS, MoH, CHSU, LUANAR)
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