DIFFERENCES IN NITROGEN AND SULPHUR UPTAKE IN CANOLA AND NON CANOLA CULTIVARS OF OILSEED RAPE (BRASSICA NAPUS L.) AS INFLUENCED BY APPLICATION TIME OF NITROGEN AND SULPHUR

Abstract

The effect of time of application of nitrogen (N) and sulphur (S) on nutrient uptake by three cultivars of oilseed rape (Brassica napus L.) was studied at Punjab Agricultural University Ludhiana during rabi 2006-07. Non canola cultivar GSL 1 recorded significantly higher nitrite reductase activity and higher nitrate reductase activity than both canola cultivars whereas opposite trend was discerned for nitrate reductase activity at 80 DAS. The differences among cultivars for N and S content at any growth stage were non significant. However, N and S uptake by seed was highest in OCN 3 and lowest in GSL 1. Combined application of N and S resulted in significantly higher nitrite reductase activity at 50 and 80 DAS and nitrate reductase activity at 50 DAS compared to their application alone or without application of N and S. The highest N uptake at all growth stages (except 50 DAS), seed and stover at harvest was registered with split application of N and S (N50+50S20+20). Both N and S applied in two equal splits (N50+50S20+20) registered higher S content and significantly higher S uptake at all growth stages, seed and stover than application of same quantity of N in two equal splits and S only at sowing or their application in three splits.