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Abstract Two field experiments were conducted at Agricultural Experiment Farm. Mallawy Research Station in 1991/ 1992 for cane crop and 1992/ 1993 for first ratoon. The ailTIof this study was to observe the effect of N sources, application time and levels on growth, yield and its components and juice quality of sugar cane variety G- T 54- 9. Split- split plot design with three replications were applied. Nitrogen sources i. e. ammonium sulphate, ammonium nitrate, urea and slow release fertilizer were ranked the main plot. Two application times as all amount after planting or the half after complete germination and the other half after one month from first dose occupied in sub plot. Nitrogen levels (zero, 80, 160 and 240 kg N/ fed.) were distributed in sub- sub plots. Planting was done on March 12, 1991 using the dry method. The results could be summarized as follows: A. Growth characters 1- Ammonium nitrate gave the highest number of plants/ m. Adding nitrogen fertilizer at two equal doses produced the highest number of plants/m. The highest number of plants/ m was obtained by using N fertilizer at 160 kg N/ fed. -~-- - --- --- ---- - ------- ------ - 68- 2- The tallest plant was obtained by usmg urea as when compared with the other sources. The application of nitrogen fertilization at one dose after planting gave the highest plant. Plant height was increased as nitrogen level was increased up to 240 kg N/ fed. at 180, 2 I0 and 240 days age. 3- The total soluble solids at 9 and 10 months ages were increased when using urea, while slow release fertilizer gave the highest total soluble solids at age 11 monthes. Adding all amount of nitrogen at planting resulting in giving the highest total soluble solids during growth stage. The total soluble solids increased by increasing the nitrogen levels. But the differences between the averages were not significant except at 11 month age. B- yield and its component characters 1- Slow release fertilizer was better than other sources as for millable cane length. The nitrogen application time resulted in increasing significantly the millable cane length. Fertilization sugar cane by nitrogen in two equal doses gave the highest millable cane length. There was a significant Increase in this trait as N level increased up to 160 kg N/ fed. 2- The stalk diameter was not significantly affected by nitrogen sources, application time and nitrogen levels. - 69- 3- The number of internodes/ stalk was significantly affected by nitrogen sources. Fertilization sugar cane by ammonium nitrate or urea tended to produce more internodes. Time of N fertilization did not affect significantly the number of internodes. The number of internodes/ stalk was increased as nitrogen levels were increased up to 240 kg N/ fed. 4- The stalk weight was significantly affected by nitrogen sources and levels, while time of application did nit show any significance effect on this trait. Using urea at 240 kg Nt fed. gave the highest stalk weight. 5- Net cane yield (toni fed.) was significantly affected by nitrogen sources, time of application and nitrogen levels. The highest cane yield was obtained when received 240 kg N/ fed.· of slow release fertilizer in two equal doses and when received 160 kg N/ fed. in one dose but the difference was not significant. 6- Juice weight / stalk (kg) increased by using ammonium nitrate when compared with the other N sources, however time of application and nitrogen levels did not significantly affect this character. 7- Both time of application and nitrogen levels had significant effect on sugar yield/ fed. However, this trait was not significantly affected by N sources. The highest sugar yield was produced by slow release fertilizer at 160 kg N/ fed. in one dose. - 70- C: Juice characteristics 1- Total soluble solids (T.S.S) was not significantly affected by the three factors under study. 2- The sucrose percentage was not significantly affected by nitrogen sources or time of application. However, nitrogen levels showed significant effect on sucrose percentage. The highest value of sucrose % was obtained by applying 240 kg N/ fed. in a form of urea at one dose but there was no difference by slow release fertilizer when applying 160 kg N/ fed. in one dose. 3- The purity percentage was significantly affected by nitrogen sources. Ammonium sulphate improved purity of cane juice when compared with the other sources. However, neither time of application nor levels of nitrogen had significant effect on purity percentage. 4- The three studied factors did not have any significant effect on reducing sugars. |