FOLIAR APPLICATION OF SELENIUM, ZINC AND COPPER IN ALFALFA (Medicago sativa L.) BIOFORTIFICATION

Biofortification of forage crops has an important role in improving the quality of plants used for animal nutrition. The field experiments were conducted in three consecutive years in Subotica, Serbia, in order to investigate the effect of Se, Zn, and Cu foliar fertilization on the yield, Se and Zn contents and nutrient efficiency, as well as on other mineral compositions of alfalfa hay. The treatments were as follows: i) control without fertilization, ii) 5 g Se ha(-1), iii) 10 g Se ha(-1), iv) 0.5 kg Zn ha(-1), v) 1 kg Zn ha(-1), vi) the combination of these two elements (0.5 kg Zn ha(-1) and Se 10 g ha(-1)) and vii) 2% Cu solution. The application of Se, Zn, and Cu had no effect on dry yield or on crude protein, P, K, Ca, Mg, Fe, Mn, Mo, and Co contents in alfalfa hay. However, Se, Zn, and Cu fertilization significantly increased the contents of Se, Zn, and Cu in alfalfa hay. The results showed that Se and Zn contents in plant biomass were significantly correlated with the applied doses of Se (r= 0.99) and Zn (r= 0.99). The production years of alfalfa and the weather conditions proved to be significant factors in fertilization efficiency.