MAIZE GRAIN-YIELD FORMATION IN DEPENDENCE ON APPLIED ZINC DOSES AND ITS CONTENT IN SOIL

Under conditions of three-year field experiments action of differentia ted zinc doses (1.5; 3 and 6 kg.ha(-1)) as affected the yield formatio n, crude protein content and resorption of macronutrients and zinc by maize gain was Investigated. The highest maize grain increments, stati stically highly significant, were found at a zinc dose of 1.5 kg.ha(-1 ). The yield increased on average by 1.01 t.ha(-1) during three years, i.e. by 10.9%, what is a highly significant result. The highest effic iency of zinc was determined in 1994 in soil which contained its low r eserve (0.7 mg.kg(-1) of soil). Zinc fertilization had a positive impa ct on the withdrawal of macroelements, particularly of nitrogen, by 44 .4 kg.ha(-1), i.e. by 18.5%. Taken nutrients were used for maize grain yield formation and quality. Crude protein content in grain on averag e for three years increased by 0.9% in fertilization variant 3 or by 1 .1% in variant 4, respectively. The highest zinc dose(6 kg.ha(-1)) res ulted in depression of yields in all experimental years. 1.5 to 3 kg.h a(-1) is considered as optimum zinc dose for grain maize in conditions of the Zahorska Lowlands in dependence on its content in soil.