Two field experiments were conducted on sandy soil at El-Kassasien Research Station Ismaillia Governorate, under drip-irrigation system , during the two successive seasons of 2004/2005 and 2005 /2006 to study the influence of N fertilizer application methods (7 N fertigation treatments) on yield and quality of two sugar beet varieties (Atose poly and Loados). A split-plot design technique was used to carry out this trial. The 7 N fertigation treatments were : Fr1: Applying the N fertilizer through soil + 3 hrs irrigation. Fr2: 3 /4 hrs irrigation + 1 1 /2 hrs fertigation + 3 /4 hrs irrigation. Fr3: 1 1 /2 hrs irrigation + 3 /4 hrs fertigation + 3 /4 hrs irrigation. Fr4: 1 1 /2 hrs fertigation + 1 1 /2 hrs irrigation. Fr5: 2 1 /4 hrs irrigation + 3 /4 hrs fertigation. Fr6: 2 1 /4 hrs fertigation + 3 /4 hrs irrigation. Fr7: 3hrs fertigation. The main plots were devoted to N fertigation treatments and the two sugar beet varieties were placed in the sub-plot units. The important results could be summarized as follow: 1. All fertigation treatments were superior to the non fertigation treatment. 2. The highest values of root, top and sugar yields and root length were recorded when Fr6 treatment was applied. 3. The highest value of TSS % were obtained when Fr5 treatment was applied, while the highest value of root diameter was obtained with Fr3. 4. Sucross % and purity % were not significantly affected by all fertigation treatments. 5. Lados variety surpassed Atose poly variety for top , root and sugar yields, TSS% , root length and diameter.

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