Influence of irrigation interval, nitrogen level and crop geometry on production of trickle irrigated lettuce

Abstract

Field experiments were conducted during winter season (October to February) of 2008-09 and 2009-10 to investigate the growth and yield response of lettuce to different irrigation intervals, nitrogen application rates and different crop geometries under trickle irrigation. The plan of experiment included three crop geometries [45 × 30 (G1); 30 × 30 (G2) and 17.5 × 30 (G3) (Row × plant spacing in cm)], two irrigation schedules [2 days (I1) and 4 days (I2) interval] and two levels of nitrogen application [60 kg ha-1 (N1) and 100 kg ha-1 (N2)]. For both the experiments there were three replications. The coefficient of variation of the emitter discharge used in trickle irrigation system was 0.059 and 0.091 in 2008-09 and 2009-10, respectively. The results revealed that lettuce raised with 17.5 cm × 30 cm crop spacing, along with two day irrigation interval and 100 kg N ha-1 application gave the maximum plant height (18.5 and 17.3 cm), leaf area index (2.37 and 2.27) and marketable yield (43.06 and 39.64 t/ha). Maximum number of leaves (19 and 16), head weight (347.4 and 312.6 g) and head diameter (13.9 and 12.5 cm) with 45 cm × 30 cm crop spacing, along with two day irrigation interval and 100 kg N ha-1 application rate. It can be concluded from field experimental data that two day irrigation interval with 100 kg N ha-1 application if coupled with closer row spacing may result in higher marketable yield in lettuce.