Yield, dry matter and N characteristics in canola as affected by fertilizer N rate and split-application ratio under high soil fertility condition

Abstract

The effects on seed yield, dry matter and nitrogen (N) characteristics under two fertilizer N rates of 240 and 270 kg ha−1 and three N split-application ratios (SAR) of basal: bolting fertilizer 7:3, 6:4 and 5:5 were investigated. Under 240 kg N ha−1 condition, seed yield was positively correlated with the number of effective pods (r = 0.90**), which was the main determinant of seed yield. Under 270 kg N ha−1 condition, seed yield was closely related to 1000-seed weight (r = 0.97**) and the number of seeds per pod (r = 0.90**), with the former appeared to be the most important determinant. The yields and numbers of effective pods in the N SAR 6:4 with N rate of 240 kg ha−1 were the highest among three SARs, while the yields of N SAR 5:5 under 270 kg N ha−1 were the lowest, attributable to the high lodging angle, low 1000-seed weight and low number of seeds per pod. Under 240 kg N ha−1 condition, the biomass, root dry weight, ratio of root to shoot, harvest index (HI), total N accumulation, N harvest index (NHI)and N utilization efficiency for grain yield (NUEg)in the N SAR 6:4 were the greatest among different SARs. The study revealed that, to achieve stable and high yields of winter canola, N recommendation at a rate of 240 kg ha−1 and N SAR 6:4 was suggested in this high soil fertility region.