Effect of Different Phosphorous Doses on Growth and Yield of Sunflower (Helianthus Annuus L.)

The analysis of variance demonstrated a significant (P<0.05) effect of various phosphorous rates on sunflower. The application was comprised of different phosphorous rates, i.e., P=0 kg ha-1 (control), P=42 kg ha-1 (30% < Recommended), P=48 kg ha-1 (20% < Recommended), P=60 kg ha-1 (recommended), P=72 kg ha-1 (20% > Recommended), and P=78 kg ha-1 (30% > Recommended). Statistical analysis showed that varying phosphorous rates significantly impacted sunflower growth and yield when compared to the control level of 0.00 kg ha-1. The test revealed that adding 78 kg ha-1 (30% more than recommended) of phosphorous resulted in the highest plant height (170.59 ± 1.261a), stem girth cm (8.80 ±0.138a), head diameter (cm) plant-1 (8.80 ±0.138a), seeds head-1 (2013.7 ± 2.292a), seed index (1000-seed weight, g) (62.42 ± 0.223a), highest seed weight head-1 (g), (82.54 ± 1.494a), seed yield (kg ha-1) (2401.7 ± 9.643a), and the oil content % (42.49 ± 0.363a). However, phosphorous 0 kg ha-1 (control) demonstrated the minimum results and was observed with plant height cm 146.67 ±0.950e, stem girth 4.78 ±0.152e cm, head diameter (cm) 30.99 ± 0.633e cm, seeds head-1 (1105.7 ± 0.633e), seed index (1000-seeds weight) (41.55 ± 0.696e), seed weight head-1 (g) (62.06 ± 1.115e), and oil content of (32.96 ± 1.644e). The experiment's results demonstrated that a phosphorous rate of 72 kg/ha (20% more than recommended) was suitable for achieving the maximum sunflower yield, as there were no significant differences when the phosphorous level was increased to 78 kg/ha (30% more than recommended).