Abstract
BackgroundDietary zinc (Zn) deficiency is widespread in sub-Saharan Africa (SSA) with adverse impacts on human health. Agronomic biofortification with Zn fertilizers and improved soil fertility management, using mineral and organic nutrient resources, has previously been shown to increase Zn concentration of staple grain crops, including maize. Here, we show the potential of different soil fertility management options on maize crops to reduce dietary Zn deficiency in Zimbabwe using secondary data from a set of surveys and field experiments.MethodsAn ex-ante approach was used, informed by published evidence from studies in three contrasting smallholder production systems in Zimbabwe. To estimate current Zn deficiency in Zimbabwe, data on dietary Zn supply from non-maize sources from the Global Expanded Nutrient Supply (GENuS) data set were linked to maize grain Zn composition observed under typical current soil fertility management scenarios.ResultsA baseline dietary Zn deficiency prevalence of 68% was estimated from a reference maize grain Zn composition value of 16.6 mg kg−1 and an estimated dietary Zn intake of 9.3 mg capita−1 day−1 from all food sources. The potential health benefits of reducing Zn deficiency using different soil fertility management scenarios were quantified within a Disability Adjusted Life Years (DALYs) framework. A scenario using optimal mineral NPK fertilizers and locally available organic nutrient resources (i.e. cattle manure and woodland leaf litter), but without additional soil Zn fertilizer applications, is estimated to increase maize grain Zn concentration to 19.3 mg kg−1. This would reduce the estimated prevalence of dietary Zn deficiency to 55%, potentially saving 2238 DALYs year−1. Universal adoption of optimal fertilizers, to include soil Zn applications and locally available organic leaf litter, is estimated to increase maize grain Zn concentration to 32.4 mg kg−1 and reduce dietary Zn deficiency to 16.7%, potentially saving 9119 DALYs year−1. Potential monetized yield gains from adopting improved soil fertility management range from 49- to 158-fold larger than the potential reduction in DALYs, if the latter are monetized using standard methods.ConclusionFarmers should be incentivized to adopt improved soil fertility management to improve both crop yield and quality.
Highlights
Zinc is an essential element required for various metabolic and enzymatic functions in humans (Hotz and Brown 2004)
Recent studies in Ethiopia have shown that greater soil organic matter content associates with greater Zn concentration in wheat (Triticum aestivum L.) grains (Wood et al 2018). These findings provide intriguing evidence that the consumption of crops grown through the increased use of organic nutrient resources and good soil management can contribute to reducing dietary Zn deficiency, and that such approaches can augment the benefits that could arise from the use of Zn fertilizers alone (Joy et al 2015, 2017)
If we assume that this deficiency prevalence contributes to the current 12,092 Disability Adjusted Life Years (DALYs) lost due to Zn deficiency in Zimbabwe, this will result in a DALYs disease burden due to Zn deficiency of ~ US$19.4 M year−1
Summary
Zinc is an essential element required for various metabolic and enzymatic functions in humans (Hotz and Brown 2004). > 75 million DALYs were lost in 2010 due to micronutrient deficiencies (hidden hunger), with ~ 25 million DALYs in sub-Saharan Africa (SSA) compared to ~ 3 million DALYs in Europe and Central Asia (Gödecke et al 2018). 9.1 million of the global DALYs lost due to hidden hunger have been attributed to Zn deficiency (Gödecke et al 2018), these are not uniformly distributed. Dietary zinc (Zn) deficiency is widespread in sub-Saharan Africa (SSA) with adverse impacts on human health. We show the potential of different soil fertility management options on maize crops to reduce dietary Zn deficiency in Zimbabwe using secondary data from a set of surveys and field experiments
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
