A Field experiment was carried out at the Experimental Station Farm in Giza, Agricultural Research
Center, Egypt, during the two successive summer seasons of 2012 and 2013. The experiment was to
study the effect of varying sources, rates of nitrogen fertilizers on fresh and dry forage yields of sudangrass,
chemical constituents, nitrate and nitrite accumulation in plant using a split-plot design with three replicates .
The main plots were assigned to nitrogen fertilizer sources (Ammonium nitrate NH4 NO3 and ammonium
sulphate (NH4)2 SO4.While, the sub-plots were occupied with rates of nitrogen fertilizer (50, 75, 100, and
125 Kg N / fed).The results indicated that the fresh and dry forage yield ton/fed, nitrogen, crude protein,
phosphorus, potassium, nitrite (NO2) and nitrate (NO3)contents were significantly decreased in the second
cutting as compared with the first one over both seasons. Using ammonium sulphate "(NH4)2 SO4" was better
than using ammonium nitrate "NH4 NO3" as a source of nitrogen fertilizer over both cuttings and seasons.
Fresh and dry forage yields of sudangrass were significantly increased as nitrogen rates increased from
50 to 75 and 100 kg N/fed and significantly decreased due to increasing nitrogen rate from 100 to 125 kg N/
fed over both seasons.It can be recommended that mineral fertilizing of sudangrass plants with 75100- kg
N/fed is better to get suitable forage yields and reduce nitrate accumulation in plant.