Alireza Pirzad - epartment of Agronomy, Faculty of Agriculture, Urmia University, Urmia, Iran
Shafie Modarees Motlagh - Student of Department of Agronomy and Plant Breeding, Science and Research Branch, Islamic Azad University, Tehran, Iran.

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 nutrient uptake by 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° 51' N and longitude 41° 44' E and 1313 m above sea level) in 2010. Results of ANOVA showed the significant effect of irrigation disruption on potassium uptake and significant interaction effect between irrigation disruptions and phosphorus on nitrogen and phosphorus uptake. Means comparisons showed that the highest percentage of seed nitrogen (4.52 %) was belonged to irrigation disruption at grain filling stage with 100 g/ha phosphorus and the lowest percent of seed nitrogen (3.3 %) was observed in normal irrigation with 150 g/ha phosphorus. The maximum of percentage of seed phosphorus (1.81 %) was obtained at the beginning of flowering with 150 g/ha phosphorus and the minimum percent of seed phosphorus (1.34 %) at normal irrigation with 150 g/ha biological phosphorus.

Brassica napus, Irrigation disruption, Nutrient uptake, Phosphorus