الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Two field experiments were conducted during two successive summer growing seasons 2013 and 2014 in an administration field at Meet Gaber village, Belbais District, Sharkia Governorate, Egypt. The experiment aimed to study the effect of planting density (D1:70000 plants/fad., D2: 105000 plants/fad., D3:140000 plants/fad. and D4: 210000 plants/fad.) and nitrogen fertilizer levels (N1: 15 kg N/fad./cut, N2:30 kg N/fad./cut and N3: 45 kg N/fad./cut) on growth characters, Fresh, dry and protein yields/fad as well as Quality and nutritive values at 1st and 2nd cuttings of three forage sorghum genotypes (G1: Sudan grass (Sorghum sudanense (Piper) Stapf, cv. Giza 2),G2: sweet sorghum (Sorghum bicolor (L.) Moench, cv. Giza 1), and G3: sorghum (Sorghum bicolor (L.) Moench) x Sudan grass (Sorghum sudanense (Piper) Stapf, cv. Surdan) as an interspecies hybrid. The obtained results could be summarized as follows: 1- Sudan grass surpassed in most of growth characters, fresh and dry yields/fad, interspecies hybrid sorghum ranked the second and followed by sweet sorghumز 2- Sweet sorghum gave higher values in most of quality and nutritive values compared to those of interspecies hybrid sorghum and sudan grass.
3- Using plant density 70000 plants/fad. led to a significant increase in fresh weight(gm/plant),crude protein and fiber content ins leaves and stems. Fresh forage yield (ton/fad.) was significantly increased due to increasing plant density up to 140000 or 210000 plants/fed. at 1st and 2nd cut in both seasons and their combined analysis. For quality and nutritive values, increasing plant density led to decreasing these characters, except Total digestible nutrients (TDN%) in leaves and stems. 4- The increase of N level from 15 to 30 and up to 45 kg N /fad. was followed by a significant increase in the aforementioned characters, except crude fiber content which was significantly decreased due to increasing N up to 45 kg/fad. at 1st and 2nd cuttings in both seasons and their combined analysis.