Effect of nitrogen and sowing dates on productivity of Brassica species

A field experiment was conducted during winter (rabi) seasons of 1998–99 and 1999–2000 at Ludhiana, to study the response of Brassica species (B. carinata A. Braun and B. napus L) to 4 levels of N (0, 75, 100 and 125 kg/ha) under 3 sowing dates (21 October, 15 November and 10 December). The productivity of Brassica species sown on 21 October and 15 November was higher over 10 December sown crop by 18.6 and 20.0% in 1998–99 and 21.6 and 17.0% in 1999–2000. Growth and yield-attributing characters were also significantly higher in 21 October and 15 November sown crop. B. napus gave 15% higher seed yield compared to B. carinata during 1999–2000, whereas the differences were non-significant during 1998–99. The seed and oil yields of Brassica species increased significantly with each successive increase in nitrogen level up to 100 kg N/ha. The seed yield obtained with the application of 100 kg N/ha was 17.00 and 15.91 q/ha during 1998–99 and 1999–2000 respectively. Interaction effects revealed that crop sown on 21 Octover 15 November and 10 December responded to N applied up to 125, 100 and 75 kg/ha, respectively, in both the years.