The Effect of Nitrogen and Sulphur Fertilizers and Growth Regulator on the Seed and Oil Yield of Canola as Second Crop in Rice Fields

The effect of chemical nitrogen (N) and sulphur (S) fertilizers, as well as a growth regulator, was studied on quantitative and qualitative traits of canola cv. ‘Hyola 401’ as a second crop in paddy fields in Baz Kia Gurab located in Lahijan, Guilan province, Iran in 2021-2022 in a split-plot experiment based on a randomized complete block design with three replications. The experimental factors included a growth regulator (Shootex) at two rates of 0 or 200 mg/L as the main plot and pure N fertilizer at four levels of 0, 90, 180, or 270 kg/L (from a urea source containing 46% N) and S fertilizer at three levels of 0, 35, or 70 kg/ha (from an ammonium sulphate source containing 24% S and 12% N) as the subplot. The results showed that the highest seed and oil yields (4081 and 1135 kg/ha, respectively) were obtained from the treatment of the growth regulator, 270 kg/ha N, and 70 kg/ha S, and the lowest (1086 and 368 kg/ha, respectively) from the treatment of the growth regulator, no N fertilizer, and 70 kg/ha S. To achieve the best results, the use of vegetative growth regulator, nitrogen and sulphur fertilizers, 270 and 70 kg/ha each, is recommended for rapeseed in the growing conditions of the region.