Effect of irrigation disruption and biological phosphorus on the biomass and oil content of canola (Brassica napus L.)

ABSTRACT: To evaluate the effect of irrigation (irrigation disruption at beginning of flowering, end of flowering, grain filling and control) and biological phosphorus (0, 50, 100 and 150 g/ha) on the yield of Brassica napus L. cv. “Hyola 401”, a split plot experiment was carried out based on randomized complete block design with four replications at the research farm of Shahid Beheshti Agriculture College (latitude 38° 51ʹ N and longitude 41° 44ʹ E and altitude of 1313 m above sea level) in 2010. Results of ANOVA showed the significant interaction effect between irrigation disruptions and phosphorus on biological yield (biomass), percentage of seed oil, oil yield and Harvest Index (HI) of oil. The highest yield of oil (300.14 kg/ha) and harvest index of oil (3.73 %) were obtained from irrigation disruption at the end of flowering and 50 g/ha biological phosphorus, and the lowest yield of seed oil (44.42 kg/ha) and harvest index of oil (0.65 %) were obtained from irrigation disruption at the beginning of flowering and without phosphorus. The highest percent of oil (43.65 %) was obtained from irrigation disruption at no disruptions with 100 g/ha phosphorus and the lowest percent (36.55 %) was obtained at the beginning of flowering stage with 150 g/ha phosphorus. Means comparisons showed that the highest biomass (10223.32 kg/ha) belonged to normal irrigation with 50 g/ha phosphorus application. The lowest biomass (6826.65 kg/ha) belonged to no phosphorus treatment and irrigation disruption at the beginning of flowering stage.