Zinc fluxes from the soil into the food chain in arid agro-ecosystems
Zinc deficiency is recognised as a major problem of human nutrition worldwide. It is particularly severe where populations depend on cereals as staple food and have an insufficient dietary intake of zinc from legumes or animal products (a widespread situation in arid regions of developing countries). Biofortification of food crops is a promising strategy to fight mineral malnutrition in these countries. In addition to breeding for crop varieties with enhanced zinc efficiency, the adaptation of farming practices such as fertilisation and other soil amendments has potential, as well, to improve the zinc density of consumed parts of food plants. Independent of the chosen strategy, sustainable solutions must consider the system of land use, agricultural management practices, food production, consumer behaviour, and human nutrition as a whole. Such an approach requires the knowledge and understanding of the relevant zinc fluxes through the system. In this project we aim (i) to identify dominant zinc pathways in human nutrition for arid regions, (ii) to analyse the effects of agricultural practices on the nutritional quality of the produced food, and (iii) to evaluate agricultural options to reduce dietary zinc deﬁciency. For this purpose, two subprojects have been deﬁned. In the ﬁrst subproject, the transfer of zinc from soil to plants in three Iranian provinces was investigated. A doctoral student collected the required information such as agricultural statistics, soil fertilisation data and management practices. In addition, a total of 245 soil and crop samples were randomly taken from the study area. The chemical analysis of these samples is almost complete. In the second subproject, the transfer of zinc from food plants to humans is being investigated. Zinc intake of the population living in urban and rural areas of Isfahan Province is being assessed in order to identify the main food sources for zinc (cereals, dairy products, meat) and to determine the proportion of zinc ingested from cereals. During a one-week visit in Isfahan, Rita Wegmüller trained the doctoral student carrying out this subproject as well as some master students of Isfahan University of Technology (IUT) involved in the collection of dietary intake data. The data is collected from several families in urban and rural areas by three-day weighed food records. Food samples collected from the families will be analysed for their zinc and phytic acid content. This dietary assessment is planned to be completed in May 2008. The outcomes of the two studies mentioned before will be used to extend a model that has been developed for the assessment of heavy metal ﬂ uxes at a regional scale in Swiss agro-ecosystems to include zinc transfer from the soil to crops and from crops to humans. Show more
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Journal / seriesAnnual Report
Pages / Article No.
PublisherSwiss Centre for International Agriculture, ETH
Organisational unit03413 - Hurrell, Richard Frederick
03427 - Frossard, Emmanuel / Frossard, Emmanuel
NotesPublished in http://dx.doi.org/10.3929/ethz-a-004260904.
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