Effect of varying doses of P, along with constant level of N, on the growth and yield of lettuce, Lactuca sativa L.

The present study was carried out to assess the effect of varying P doses (0, 45, 53, 61, 69 and 77 kg per hectare) along with constant level of N (85 kg per hectare) on the growth and yield of lettuce. The experiment was laid out in randomized complete block design with four replications. The variety used for this experiment was Grand Rapid, while the plot size was 2.5 x 2 meters (5m-2). The results revealed that there was a highly significant effect on different P levels on plant height, breadth of leaves, vertical and horizontal diameter of head, weight of single plant and yield per hectare. The plot received 77kg and 69kg P along with 85kg N produced maximum plant height (2.81 and 25.24 cm), breadth of leaves (16.47 cm and 16.10 cm), vertical diameter of head (23.01 cm and 22.59 cm), horizontal diameter of lettuce head (23.77 cm and 23.20 cm), weight of single plant (164.22 g and 161.53 g), yield per plot (6.27kg and 6.15kg) and yield per hectare (12528kg and 12298kg) respectively. The plots treated with 61kg and 53kg P per hectare along with 85kg N per hectare, ranked third and fourth with average plant height of 24.55 and 23.98 cm. breadth of leaves 14.82 cm and 14.19 cm, vertical diameter of head 21.36 cm and 20.55 cm. horizontal diameter of lettuce head 21.88 cm and 21.37 cm, weight of single plant 156.22 cm and 149.35 cm, yield per plot 5.63kg and 5.33kg, yield per hectare 11248.25kg and 10655kg, respectively. The lowest values for plant height (20.83 cm), breadth of leaves (12.55 cm), vertical diameter of head (18.31 cm), horizontal diameter of lettuce head (19.11 cm), weight of single plant (139.68g), yield per plot (5.01kg) and yield per hectare (10007kg). The lettuce growth and yield contributing characters were significantly affected by application of P and as the P level was increased, a considerable improvement in the crop growth and yield was observed.