Rapeseed (Brassica campestris L.) as influenced by varying levels of nitrogen and sulphur under normal and late sown conditions of Kashmir Valley

The purpose of this research work carried out in split plot design at the Shalimar Campus of Sher-e-Kashmir University of Agricultural Sciences and Technology, Kashmir during the rabi seasons of 1995 to 1997 on the silty clay loam soil of medium fertility, was to study the influence of nitrogen (0,30,60 and 90 kg ha-1) and sulphur (0,20 and 40 kg ha-1) under normal (5 Oct.) and late (30 Oct.) sown conditions on the growth and yield behaviour of rapeseed (Brassica campestris L.). Normal sowing date was found to cause significant improvement in various growth characters viz., plant height, dry matter production, leaf area index (LAI), primary and secondary branches, and yield attributing traits like number of siliquae plant-1, seed siliqua-1 and 1000-seed weight. Seed and straw yield and harvest index (H.I) was also significantly influenced by the normal sowing data. Furthermore, the late sowing caused reduction both in flowering and maturity period. Discernible improvement was observed in plant height, dry matter production and LAI up to 90 kg N ha-1, however, the primary and secondary branches, various yield attributing traits and H.I. increased markedly up to 60 kg N ha-1. Significant increase in seed yield (pooled data) was recorded up to N levels of 90 kg ha-1 under the normal sown conditions, whereas under the late sown conditions, the higher seed yield was obtained with 60 kg N ha-1. Sulphur application up to 20 kg ha-1, created detectable improvement in all the growth characters and yield and yield attributing traits; however, primary and secondary branches were not influenced by the S fertilization. Late sowing significantly improved the N content of plant (at various growth stages studied), and protein and S content of seeds as well; nevertheless, N and S uptake at various growth stages and the oil yield was beneficially influenced by the normal sowing conditions. N and S content of the plant tissue and their uptake increased significantly with N level of 60 kg ha-1, whereas, protein and S content of the seed improvement only up to 30 kg N ha-1. Further, the most important character from the standpoint of quality viz., oil yield, showed marked improvement with application of N up to 60 kg ha-1. N and S content of the plant tissue and their uptake was found to be discernibly improved with 20 kg S ha-1. Protein and S content of seeds increased up to 40 kg S ha-1; however, the oil yield showed marked improvement with the S level of 20 kg ha-1. Yield response to N and S was found to be quadratic (pooled data). Optimum dose of N for normal and late sowing dates was found to be 93.44 and 69.51 kg ha-1, respectively. Further, both optimum and maximum yields were realized with 40 kg S ha-1, but differences between S40 and S20 levels were very close. Maximum net profit of Rs. 6378.95 ha-1 for normal sowing date was realized with 90 kg N ha-1. Further with respect to S fertilization, the maximum net profit of Rs. 4879.80 ha-1 was recorded with 20 kg S ha-1. Results of the present study indicated that for realizing higher seed and oil yield along with improved quality characters of rapeseed (Brassica campestris L..) in Kashmir Valley, application of 90 and 20 kg of N and S ha-1, respectively under the normal sown conditions (5 Oct.), and 60 and 20 kg of N S ha-1, respectively under the late sown conditions (30 Oct.), were found to be the most appropriate rates of respective nutrient