Effects of Sources and Rates of Nitrogen on Yield and Quality of Canola

Canola, like, other crops has specific nutritional requirements. By identifying and meeting such requirements, we can increase the yield and quality of this important crop. A randomized complete block factorial experiment with 15 treatments and 3 replications was conducted at Shavoor Agricultural Research Station of Khuzestan to determine the best rates and sources of nitrogen fertilizer with respect to canola yield and quality. The treatments included five rates of nitrogen (0, 60, 120, 180, and 240 kg/ha) and three sources of nitrogen fertilizer (urea, ammonium nitrate, and ammonium sulfate). Analysis of variance of data on canola yield and per cent oil showed that nitrogen rates significantly (  = 0.01) affected the yield and oil content so that the highest yield of 2.5 tons/ha was obtained with 240 kg N/ha, but the increasing rates of nitrogen reduced per cent oil even though the total oil yield increased; more specifically, the highest oil yields of 1070, and 1153 kg per hectare were obtained with 180 and 240 kg N per hectare, respectively, as compared with the lowest yields of 325 kg/ha from the control tests. Nitrogen sources also significantly affected (  =0.05) the yield but not the yield components. Ammonium nitrate and sulfate were in the same group and urea in a different group with respect to yield improvement. Interactive effects of rates and sources of nitrogen on canola seed yield was found to be significant ( =0.05) so that the highest yield of 3 tons/ha was obtained with 240 kg N/ha as ammonium nitrate. The interaction of years, rates and sources on yields and oil contents were found to be statistically insignificant.