1. Department of Chemistry and Biochemistry, Faculty of Agriculture; University of Belgrade; 11080 Belgrade Serbia
2. Department of Pedology and Geology, Faculty of Agriculture; University of Belgrade; 11080 Belgrade Serbia
3. Institute of Chemistry, Technology and Metallurgy; University of Belgrade; 11000 Belgrade Serbia
4. Maize Research Institute Zemun Polje; 11185 Belgrade Serbia
5. Department of Agrobotany, Faculty of Agriculture; University of Belgrade; 11080 Belgrade Serbia