Abstract
A field experiment was conducted during spring seasons of 1992 and 1993 at the Research Farm of Janta Vedic College, Baraut, Meerut (Uttar Pradesh) to determine the optimum levels of irrigation, N, and P for spring sunflower (Helianthus annuus L. var. Morden) on a loamy soil (Alfisol). Irrigation applied at 0.8 Irrigation Water:Cumulative Pan Evaporation (IW:CPE) ratio, N at 120 kg ha-1, and P2O5 at 80 kg ha-1 produced maximum plant height, number of leaves, dry weight per plant at harvest, and leaf area index (LAI) at 90 days after sowing. Irrigation applied at 0.6 IW:CPE ratio produced significantly more seed yield (2283 kg ha-1), larger head diameter (17.2 cm), greater number of seeds per head (628), and higher seed weight per head (32.4 g) over 0.4 IW:CPE ratio. Maximum sunflower seed yield (2503 kg ha-1), head diameter (17.4 cm), number of seeds per head (640), and seed weight per head (33 g) were found with irrigation applied at 0.8 IW:CPE ratio. The diameter of head, number and weight of seeds per head, and seed yield increased with increasing levels of N and P.
