Abstract

A field experiment was conducted during the seasons 2015–16 and 2016–17 in the fields of Department of Horticulture, College of Agricultural Engineering Sciences, University of Baghdad in order to study the effect of foliar application with Humistar, Dolphin Plus and nitrogen fertilizer (Novatic Soluble 21) and interaction between them as well as the control treatment (NPK) on growth and yield of lettuce plant. Seedlings were planted using the randomized complete block design with three replications. The interaction treatment between organic and amino acids was superior in nitrogen percentage in the first season, and phosphorus and chlorophyll percentage in the second season by giving (2.4700%, 0.4167% and 0.536 mg/g), respectively, also it was superior in nitrate concentration and head circumference in both the seasons (581.00 ppm, 584.00 ppm, 66.70 cm and 43.30 cm), respectively. While the treatment of nano-fertilizer was superior in nitrogen percentage in the second season and in phosphorus percentage in the first season (2.4633 and 0.3900%), respectively. The interaction treatment between nano-fertilizer and amino acids was superior in potassium percentage and the amino acid (proline) concentration in the two seasons by giving 2.2600%, 2.2133%, 8.40 mg/g and 8.60 mg/g), respectively. While in the stem length, stem diameter, number of leaves per plant, head weight, total yield, in both the seasons, and chlorophyll ratio in the first season, the treatment of nano-fertilizer was superior in all of them by giving 8.33 cm in both the seasons, 3.80 mm, 2.80 mm, 57.3 leaves/plant, 37.3 leaves/plant, 922 g, 821 g, 2.767 kg, 2.464 kg and 0.5500 mg/g, respectively.