عنوان مقاله [English]
This research was conducted during four continuous periods at Kamalabad Karaj. The objective was to determine the effect of various N-fertilizers and the rate of applications was used. Factors consisted of sources of N-fertilizer (ammonium sulfate, ammonium nitrate, urea and S.C.U), and rate of application (0,120,240 and 360 kg/ha). The leaf area index, root yield and shoot weight were measured and a complete analysis of root was performed for each year of the experiment. Leaf and soil analysis were done in order to determine the nutrients situation in plants during the growing season. The data analysis showed that N-fertilizers have significant effect on leaf area index, root nitrogen, shoot weight and molasses sugar. Nitrogen rate had a significant effect on all measured quality parameters except on the Potassium. The high rate of fertilizer application caused higher yield and increased root impurities, but the highest white sugar yield (5.3 kg/ha) obtained in this experiment was found to be the one related to the highest rate of N-fertilizer with 300 kg/ha pure N, regardless of the source of the fertilizer.