EFFECT OF IRRIGATION AND NITROGEN ON YIELD AND YIELD COMPONENTS OF 2 RAPESEED CULTIVARS

A field experiment was carried out to determine the effect of irrigati on and nitrogen on two cultivars of oilseed crops (Brassica napus L, c v. canola and Brassica campestris; L. cv rapeseed) on a sandy-clay-loa m soil during 1993-1994. The mean plant height ranges for canola were: 1.20-1.40 m (well water) and 1.40-1.57 m (aquaculture effluent); and for rapeseed from 1.281.52 m (well water) and 1.41-1.58 m (aquaculture effluent) in different fertilizer treatments. Mean biomass yield for canola ranged between 14.60-17.84 Mg ha(-1) (well water) and 14.09-19. 51 Mg ha(-1) (aquaculture effluent); and for rapeseed from 16.67-19.51 Mg ha(-1) (well water) and 12.70-20.74 Mg ha(-1) (aquaculture effluen t). The mean seed yield for canola varied from 2.65-3.44 Mg ha(-1) (we ll water) and 3.02-3.74 Mg ha(-1) (aquaculture effluent): and for rape seed from 2.73-3.26 Mg ha(-1) (well water) and from 2.62-3.29 Mg ha(-1 ) (aquaculture effluent). The mean straw yield ranges for canola were: 12.01-14.39 Mg ha(-1) (well water) and 13.65-15.93 Mg ha(-1) (aquacul ture effluent); and for rapeseed from 11.67-13.28 Mg ha(-1) (well wate r) and 9.83-17.45 Mg ha(-1) (aquaculture effluent). The mean oil conte nts for canola were 30.92-36.12% (aquaculture effluent) and 32.47-35.7 8% (well water); and for rapeseed from 30.15-34.53% (aquaculture efflu ent) and 33.50-35.96% (aquaculture effluent). The mean protein content s of straw were 5.42-6.44% (canola) and 3.78-4.37% (rapeseed) in diffe rent fertilizer treatments, Application of 175 kg N ha(-1) with 50 kg P ha(-1) showed significant effect on crop yield under both types of i rrigation water. Based on the results of this study, it appears that c ultivars of rapeseed recently introduced from Canada have an excellent potential as oilseed crops in Saudi Arabia.