The trace element zinc (Zn) is an essential component of plants, animals and humans. Insufficient Zn supply is one of the most widespread problems in human nutrition worldwide. Zinc deficiency is particularly frequent where populations depend on cereals as staple food and lack access to meat and other sources of easily absorbable Zn in their diets. In many regions it is related to low Zn densities in cereal grains resulting from low availability of Zn in the soils of these regions. The problem is mostly not due to lack of Zn in soil per se, but to a lack of soil Zn in a form in which it is well accessible for uptake by the plants. For this reason, Zn deficiency is also often a limiting factor for crop yields in developing regions. Bio-fortification of cereal grains with Zn is an approach addressing the problem of Zn deficiency in humans and crop production at the same time by increasing plant Zn accumulation. In this project we investigate how organic matter can be used best in agricultural soil management to enhance the nutritional quality of wheat grains with respect to Zn density, while at the same time alleviating Zn deficiency stress to the plants and promoting soil fertility. This is particularly important for farming that primarily or even exclusively relies on organic matter such as crop residues, green and animal manure for fertilization. The idea is not only to use these substances as Zn sources substituting mineral Zn fertilizers, but also that their input into soil with low Zn availability mobilizes resident soil Zn for plant uptake. Unfortunately, wheat also contributes substantially to human cadmium (Cd) loads and due to excessive Cd inputs in the past there is a legacy of Cd pollution in many agricultural soils. Being sister elements, Cd and Zn share many similarities in their chemical behavior. Thus, an important aspect of this project also is to enhance Zn density without increasing Cd accumulation in wheat grains.
Research and coordination