The field experiment was conducted at the Department of Agronomy, Poznan University of Life Sciences, on fields of the Swadzim Teaching and Experimental Station in the years of 2009-2011. It was carried out in a random block design with 3 experimental factors in 4 field replications. The aim of the experiment was to investigate the effect of 4 doses of urea (0, 50, 100, 150 kg N.ha(-1)) and 2 doses of magnesium (0, 25 kg MgO.ha(-1), in the form of kieserite) on the dynamics of dry matter accumulation in the initial growth period (BBCH 15-16) in 2 hybrid types of maize - ES Palazzo [FAO 230-240] and ES Paroli [FAO 250] of the stay-green type (SG). It was found that dry matter in the aboveground parts of a single plant, yield of dry matter and its content at the 5-6 leaf stage were not significantly influenced by the dose of nitrogen within the range 50-150 kg N.ha(-1). Recorded values of these traits differed significantly in relation to the control (0 kg N.ha(-1)). The stay-green hybrid was characterized by a significantly greater vigour of initial growth in comparison to the traditional cultivar. The dynamics of initial maize growth expressed in terms of dry matter accumulation was most strongly limited by the deficit (a lack of available resource) of phosphorus in soil. The nutrient status of maize at the 5-6 leaf stage was to a greater degree determined by weather conditions than doses of N, Mg, and type of maize hybrid. Maize grain yield was negatively correlated with the sum of absolute values of corn nutritional status indexes in the 5-6 leaf stage (BBCH 15-16) but positively correlated with single plant dry matter of above-ground parts and dry matter yield in the discussed developmental stage.
