Productivity of sunflower as influenced by NP fertilization and row spacings

Seed of sunflower variety HO-1 were drilled in three row spacing (60, 75 and 80 cm) and fertilized with four different NP, i.e. 70-35, 105-52.50, 140-70 and 175-87.50 kg per ha. The result shows that sunflower sown in narrow spacing (60 cm) produced taller plant (185.79 cm), application of 175-87.50 kg NP per ha also recorded maximum plant height (184.06 cm), while the interaction of 60 cm row spacing and higher dose of fertilizer (175-87.50 kg NP per ha) recorded maximum plant height. Maximum stem girth was recorded in case of 90 cm row spacing (4.02 cm), 175-87.50 kg NP per ha (3.79 cm) and the interaction of 90 cm row distance and 175-87.50 kg NP per ha (4.08 cm) respectively. Greater number of leaves was recorded under wider row spacing 90 cm (14.28 per plant), application of higher dose of 175-87.50 kg NP per ha (14.20/plant) and the interaction of 90 cm row spacing and 175-87.50 kg NP per ha (118.10 per plant) respectively. Days to flowering affected significantly (P less than 0.01) by the row spacing and NP fertilizer, while non-significant difference between their interaction. Longer days to flowering was recorded in case of 90 cm row spacing (68.03), high dose of 175-87.50 kg NP per ha (69.37) and the interaction of 90 cm row distance and 175-87.50 kg NP per ha (72.78). The differences in days to maturity among row spacing and NP fertilizer were highly significant. Whereas, their interaction was non-significant, Sunflower sown in wider row distance resulted in longer days to maturity (94.72), similarly application of high dose of NP 175-87.50 kg per ha also took maximum days to maturity (95.38) while the interaction of 90 cm row distance and 175-87.50 kg NP per ha recorded maximum days to maturity (98.35). Wider row spacing as well as high dose of fertilizer 175-87.50 kg per ha NP and their interaction individually recorded maximum head diameter 16.37, 15.22 and 16.35 cm respectively. Maximum number of seeds was recorded in case of 90 cm row spacing (903 per head), 175-87.50 kg NP per ha (943.33 per head) and the interaction of 90 cm row distance plus 175-87.50 kg NP per ha (980 per head). Maximum seed weight was recorded in case of 90cm row spacing (58.578) and their interaction (62.30 g) respectively. Greater seed index was recorded in case of wider row spacing (59.61g), high dose of NP (61.67g) and their interaction (64.50g). Sunflower sown in a narrow row (60cm) gave maximum seed yield (1547.50kg per ha), among NP levels application of 175-87.50 kg NP per ha recorded greater seed yield 1993.33 kg per ha. While the interaction of 60 cm row spacing and 175-87.50 kg NP per ha gave maximum seed yield (2150 kg per ha). It may be concluded that sunflower sown in a wider row distance increased flowering and maturity days, and all yield component, while plant height and seed yield was greater in narrow row spacing. NP applied at 140-70 or 175-87.50 kg per ha produced equally maximum seed yield.