The field experiment was carried out in 2015–2017 on a family farm in Toczyski Czortki, in the Mazovia voivodeship in Poland. The experiment was set up in a split–split–plot system in three replications. The area of one plot was 30 m−2. The studied factors were: I—two maize varieties: PR38N86 (medium late hybrid cultivar 280 FAO), P8400 (medium early hybrid cultivar 240 FAO); II—four doses of nitrogen fertilization: 1. control object—without the use of nitrogen (0 kg N·ha−1), 2. nitrogen dose—80 kg N·ha−1 (applied once before sowing), 3. nitrogen dose—120 kg N·ha−1 (applied once before sowing), 4. nitrogen dose—160 kg N·ha−1 (applied once before sowing); III—four types of biostimulants used: 1. control object—without using a biostimulant, 2. Asahi®SL biostimulant: I term—four-leaf phase (BBCH 14) at a dose of 0.60 dm3∙ha−1, II term—eight-leaf phase (BBCH 18) at a dose of 0.60 dm3∙ha−1, 3. Improver® biostimulant: I term—four-leaf phase (BBCH 14) at a dose of 1.00 dm3∙ha−1, II term—eight-leaf phase (BBCH 18) at a dose of 0.60 dm3∙ha−1, 4. Zeal® biostimulant: I term—six-leaf phase (BBCH 16) at a dose of 2.00 dm3∙ha−1. The aim of the study was to determine the effect of nitrogen fertilization and the use of biostimulants on the size and quality of yield of two varieties of maize grown for grain. Based on the conducted research, it was found that nitrogen doses influenced the amount of maize grain obtained. The highest yields were obtained using 120 kg N∙ha−1. Nitrogen doses significantly affected the studied maize yield components. The dose of 120 kg N∙ha−1 increased the number of grains in the cob, while the dose—160 kg N∙ha−1 exerted the best effect on obtaining the highest values of a thousand seeds. The biostimulants used in the experiment significantly affected the mass of one thousand seeds and the number of grains in the cob. In addition, Asahi®SL, Improver® and Zeal® biostimulants increased maize yield in each growing season studied.
Effect of nitrogen fertilization on productivity and quality of Mombasa forage (Megathyrsus maximum cv. Mombasa)