Varietal Differences in Brassica Fodder as Affected by Nitrogen Topdressing and Seeding Date

Two experiments were carried out both in spring and fall with cultivars of rape (Brassica napus spp.) and C.O. (B. campestris x B. oleracea). Both cullivars showed lillle increase in plant length in spring sowing with nitrogen topdressing, but the increments were higher in earlier topdressing (T l) and later topdressing (T2) than in control in autumn sowing, although the difference was not significant. There was no difference in the number of leaves throughout the growing stages between the N topdressing treatments in spring and autumn sowing. Leaf area was greater in Tl and T2 than in control in early seeding in spring sowing, but this tendency was reversed in late aeeding, and in autumn sowing the leaf area of TI was highest. There was no difference in dry matter yield between the treatments in spring sowing, but the difference (not significant) between the N topdressing treatments was found to be high in autumn sowing.