Nutritive value of spelt (Triticum aestivum spp. spelta L.) as influenced by the foliar application of copper, zinc and manganese

The research determined crop yield, content of mineral nutrients (Cu, Zn, Mn and Fe), protein and its composition in the grain of the spelt variety 'Schwabenkorn' as affected by the foliar application of micronutrients. A field experiment was carried out during 2011-2013 at the Research Station in Tomaszkowo (53 degrees 72 N, 20 degrees 42 E), Poland. Cu, Zn and Mn and microelements together (Cu + Zn + Mn) with mineral fertilisers were applied. Nitrogen (N) was applied to all the plots in a dose of 90 kg ha(-1), triple superphosphate in a dose corresponding to 30.2 kg ha(-1) P, and potassium salt in a dose of 83.1 kg ha(-1) K. Copper (1.0% solution of CuSO4 x 5H(2)O), zinc (1.0% solution of ZnSO4 x 7H(2)O) and manganese (0.5% solution of MnSO4 x 5H(2)O) were foliar-applied as water solutions at the stem elongation stage. The mineral fertilisation, including micronutrients (individually or in combination), changed the contents of mineral nutrients, protein and the composition of its individual fractions in the grain. It was observed that the grain had high Cu, Mn and Fe content. The application of Mn, as well as micronutrients used in combination (Cu + Zn + Mn) as an addition to NPK fertilisation, increased the content of Fe, Zn and Mn in spelt grain. The application of Zn increased Fe and Zn content, while the application of Cu increased the content of Mn in grain. The total protein content in spelt ranged from 12.4% to 13.5%. Storage proteins proved to have the highest share in the total protein. Additional application of Cu, Zn and micronutrients in combination had a positive impact on the gliadins: glutenins ratio. Foliar application of Mn increased the content of omega, alpha/beta, gamma gliadins, and reduced that of low molecular weight glutenins. Foliar spraying with Cu reduced the content of alpha/beta and omega gliadins. Supply of Zn decreased alpha/beta content and increased the content of the high molecular weight glutenins fractions. The application of the micronutrients in combination reduced the content gliadin. and increased the content of high molecular weight and low molecular weight glutenins. The cultivation year was a significantly differentiating factor for the grain yield, mineral nutrient content (Fe, Zn and Mn) and the content and composition of protein fractions (with the exception of high molecular weight glutenins).