Effect of Nutrients Composition on The Growth Parameters of Two Lettuce Varieties in Hydroponic Culture With Solid Growing Media

A greenhouse research study was conducted at Golestan Agricultural Science and Natural Resources Research Center, Gorgan, in autumn and winter 2021, to investigate the effects of three different nutrient solutions on the yield and growth parameters of two local lettuce cultivars grown in solid growing media of hydroponic system. Two local lettuce cultivars (Var1 and Var2) were subjected to different nutrient solutions. Three nutrient solutions were different in nitrogen (N), potassium (K) and calcium (Ca) concentrations. The control nutrient solution consisted of concentrations 180, 210 and 190 mg L-1 for N, K and Ca. Corresponding concentrations were 140, 150 and 140 mg L-1, and 220, 270 and 220 mg L-1 for N2 and N3 nutrient solutions, respectively. The experiment was conducted as a factorial in completely randomized design with 3 replications and two factors of cultivar type (Var1 and Var2) and nutrient solution (control, N2 and N3). Based on the results, the fresh and dry weights were not significantly different between the two cultivars, but significant differences were observed for other traits. Among the nutrient solution treatments, the highest fresh weight was obtained in N3 nutrient solution (17.1 and 12.5% greater than N2 and control, respectively). Using N3 nutrient solution increased leaf dry weight (by 17.6 and 7.5%), leaf number (by 12.7 and 17.0%), leaf width (by 9.1 and 1.5%), leaf length [by 4.8 and -1.5% (not significant)], root fresh weight (by 85.4 and 58.9%), and root volume (by 264.7 and 186.5%) compared to N2 and control, respectively. Therefore, the N3 nutrient solution increased the shoot and root growth and can be suggested for maximum lettuce production in hydroponic culture.