Nitrogen and phosphorus management strategy for better growth and yield of sunflower (Helianthus annuus L.) hybrid

This study conducted during autumn season, 2010 investigated the effect of nitrogen and phosphorus on sunflower hybrid Hysun-33. The experiment was planned in randomized complete block design (factorial arrangement), with three replication, having net plot size of 3 x 7 m. The experiment comprised of 9 treatments, three levels of nitrogen and phosphorus, viz., 85, 135, 185 kg N ha -1 , and 50, 75, 85 kg P ha -1 . Nitrogen affected all estimated characters significantly, except plant population, while, phosphorus did not show significant effect on plant population and plant height. All other parameters, as leaf area plant -1 , head diameter, 1000- achene weight and achene yield were affected significantly by different nitrogen and phosphorus levels. Interactive effects of nitrogen and phosphorus were significant in all these cases. The highest achene's yield (2584 kg ha -1 ) was obtained with the application of 135-75 kg NP ha -1 as against the lowest (1491kg ha -1 ) at 85-50 kg NP ha -1 .