In line with the XDegree project implementation plan, within the Interreg IPA Cross-border Cooperation Programme Croatia-Serbia, a field experiment of corn silage hybrids (Velimir, OSSK617, OSSK602, OSSK635) was sowed at two sites, in Sombor (Serbia) and in Budrovci (Croatia). The entire fertilization process was designed according to the soil analyses, and was thus divided into basic and starter fertilization. The sowing of the experiment of all hybrids was carried out at two rates 70000 seeds/ha and 80000 seeds/ha. The total quantity of nitrogen was levelled using the fertilizer Calcium Ammonium Nitrate – CAN (27%N), so that we have 4 fertilization options: control (150 kg/ha N), G1 (170 kg/ha N), G2 (190 kg/ha N) and G3 (210 kg/ha N). During the vegetation period, phenophases and stages in the organogenesis of the corn hybrid development were monitored, and marking of plants was also conducted for the purpose of biomass chemical analysis.