The effect of nitrogen fertilizer rates on green biomass and dry matter yield of Sorghum sp. at different growth stages

The paper investigated the production properties of three sorghum genotypes: NS-Džin (forage sorghum), Zora (Sudan grass) and Siloking (interspecies hybrid) in terms of different nitrogen rates used in side dressing in 2009 and 2010. The subject of study was green biomass and dry matter yield in the stages of intensive growth and tasseling. The results have shown that there have been significant fluctuations in production indicators between the genotypes. In the total average, the lowest yield was recorded for the Sudan grass (85.41 t ha-1). Significantly higher yields were recorded for the interspecies hybrid (90.22 t ha-1) and the forage sorghum (93.51 t ha-1). Although the effect of nitrogen rates depended on weather conditions, i.e. rainfall distribution, the optimal nitrogen rate in both years was 180 kg ha-1.