Effect of Nitrogen and Potassium Levels on Yield and some of the Agronomical Characteristics in Mustard ( Brassica juncea )

A field experiment was carried out at Qazvin-Iran during 2009-2010 to assess the effect of different levels of nitrogen (N 0 , N 75 , N 150 and N 225 kg ha -1 ) and potassium (K 0 , K45, K 90 and K 135 kg ha -1 ) on yield and some of the agronomical characteristics in Mustard ( Brassica juncea ). Experiment was conducted as factorial randomized complete block design with three replications. The results showed that increased amount of nitrogen and Potassium up to 225 kg N ha -1 and 135 kg K ha -1 respectively had a positive and significant (p225, K 135 kg ha -1 and N 0 , K 0 kg ha -1 respectively. However, increased levels of nitrogen and potassium had a significant effect on seed oil percentage (SOP) and harvest index (HI) but showed no consistent trend. The highest and lowest values of seed oil percentages were obtained in the treatment of N 75 , K 90 kg ha -1 and N 0 , K 0 kg ha -1 , also the maximum and minimum of harvest index were recorded in the treatments N 225 , K 90 and N 75 , K 0 kg ha -1 . Moreover the results indicate that the interaction effect of nitrogen and Potassium on all of the characters being studied was significant (p<0.01).