EFFECT OF NITROGEN AND POTASSIUM ON THE CROWTII AND YIELD OF LETTUCE (Lactuca sativa L.)

Abstract

An experiment was conducted at the Horticulture Farm or Sher-c-Bangla Agricultural University, Dhaka-1207, during the period from November 2006 to March 2007 to study the effect of different levels of nitrogen viz., no nitrogen (N0),115 kg N/ha (N1), 125 kg NI ha (N2) and 135 kg N/ha (N3) and potassium viz; no potassium (K0), 120 kg K20/ha (K 130 kg K20/ha (K2) and 140 kg K20 /ha (K3) on the growth and yield of lettuce. The experiment was conducted in a Randomized Complete Block Design with three replications. Application of Combined effect of 135 kg N/ha (N3) with 130 kg K20/ha (K2) produced the highest yield (27.71 t/ha) and the lowest (19.79 t/ha) was recorded from control. The benefit cost ratio (BCR) was maximum (3.27) in the treatment combination of 135 kg N/ha (N3) with 130 kg K20/ha (K2) whereas, the minimum (2.57) benefit cost ratio (BCR) was obtained from control treatment. 1), different levels of nitrogen and potassium significantly influenced the growth and yield of lettuce. The highest yield and yield contributing values of different parameters were recorded from 135 kg N/ha (N3) in all days after transplanting (DAT) whereas, the plants received no nitrogen produced the lowest. However, the highest plant height (21.56 cm), number of leaves (25.08), leaf length (23.52 cm), leaf breadth (21.53 cm), fresh weight of plant (339.74 g), dry matter content (13.81%) and yield (28.29 t/ha) was obtained from 135 kg N/ha (N3) while the lowest was recorded from control treatment. Application of different doses of potassium showed significant differences among yield and different yield contributing characters at different days after transplanting (DAT). The highest plant height (21.08 cm), number of leaves (26.41), leaf length (23.29 cm), leaf breadth (22.04 cm), fresh weight of plant (325.82 g), dry matter content ( 12.32%) and yield (27 .14 t/