Effect of Sources and Rates of Nitrogen Fertilizers on Forage Yield and Nitrate Accumulation for Sudangrass

A Field experiment was carried out at the Experimental Station Farm in Giza, Agricultural ResearchCenter, Egypt, during the two successive summer seasons of 2012 and 2013. The experiment was tostudy 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 ammoniumsulphate (NH4)2 SO4.While, the sub-plots were occupied with rates of nitrogen fertilizer (50, 75, 100, and125 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 secondcutting as compared with the first one over both seasons. Using ammonium sulphate "(NH4)2 SO4" was betterthan 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 from50 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- kgN/fed is better to get suitable forage yields and reduce nitrate accumulation in plant.