Effect of nitrogen and planting dates on yield and yield components of head lettuce grown in soilless culture

Abstract

The objective of this study was to determine the effect of different N applications with different planting dates on yield, leaf nutrients and some quality parameters of head lettuce (Lactuva sativa L. var. capitata cv. Bombola) grown in substrate-culture. The experiment was conducted in an unheated plastic polyethylene (PE) covered greenhouses of the Ege University Bayındır Vocational Training School in Turkey during the winter-early spring of 2016-2017. The trial was established in a randomized block design (RBD) with four replications. In this study, the development and yields ​​of iceberg seedlings, grown at four different planting dates (8th and 23th of February; 9th and 23th of March), were determined under three different nitrogen applications (75, 150, and 250 mg N L−1). The results showed that the studied traits were affected by the treatments, so that the highest yield (334 g head−1), number of leaves (39), DW (4.56%), and Vit.C (13.45%) was obtained on 23th of Feb. (second planting date). According of Nitrogen applications, highest yield (399 g/head), number of leaves (40), DW (5.13%) was found in 150 mg L−1 N application. Overall results indicated that the most suitable cultivation period for iceberg was February, which was the first (8th Feb.) planting date in this current study. Second planting date of experiment (23rd Feb.) was also acceptable for the suitable cultivation. It was also concluded that 75–150 mg N L−1 applications could be recommended for the nutrition of iceberg in soilless culture.