IMPACT OF RATE AND TIMING OF NITROGEN APPLICATION ON YIELD AND QUALITY OF CANOLA (BRASSICA NAPUS L.)

Canola crop is substituting the indigenous rape and mustard crops due to its high quality edible oil and to its ability to grow well on rain and canal irrigated areas. Nitrogen is one of the most important nutrients for growth and development. A two-years field study (Nov. 2001-April 2003) was carried out to determine optimum N level and stage of its application for canola crop under irrigated conditions of Faisalabad, Pakistan. Five N levels (0, 30, 60, 90 and 120 kg ha(-1)) were maintained at different times i.e., full N at sowing, 1/2 N at sowing + 1/2 N at branching, 1/2 N at sowing + 1/2 N at flowering and 1/2 N at branching + 1/2 N at flowering. The total dry matter (TDM), crop growth rate (CGR), leaf area duration (LAD), seed yield, oil yield and protein content were significantly affected by different nitrogen rates. The highest N level (120 kg ha(-1)) produced maximum values for all these traits as compared to minimum in control during both years of study. Time of nitrogen application did not significantly affect TDM, CGR, protein and oil contents however, split application of nitrogen (1/2 at sowing + 1/2 at branching or flowering) produced significantly higher seed and oil yield than full nitrogen at sowing or its split application as 1/2 at branching + 1/2 at flowering.