Response of lettuce to humic acid and salt stress condition under soilless culture system

Abstract EN

The study was carried out at the private Farm of Borg El Arab, Alexandria, Egypt, during the seasons of (2016 / 2017 and 2017 / 2018) to study the effect of humic acid on lettuce yield under salt stress condition using soilless culture system.

The experiments were carried out in a Factorial experiment consisted of sixteen treatments arranged in a Randomized Complete Block Design (RCBD) with three replicates for each treatment.

The humic acid rates (0, 100, 200 and 400 mg / l) were arranged in the main plots, whereas, the four salt stress rates (control, 400, 800 and 1200mg / l) were arranged in the sub plots.

The results indicated that, the yield and its components gradually increased with the increasing of humic acid rate at 400 mg / l such as, (head diameter, head fresh weight, head dry weight and yield / fed).

Humic additions led to increase NPK content of lettuce leaves, total carbohydrates percentage and vitamin C content as compared with control treatment which recorded significantly decreased in all studied characteristics in both seasons.

On another hand, salinity treatments significantly decreased all yield and its components whereas, sodium chloride at 1200 mg / l recorded the negative effect on head diameter, head fresh weight, head dry weight and yield/fed, also, it caused a significant decrease in chemical composition such as (N,P,K,Ca, Mg and Na), total carbohydrates percentage and vitamin C content of lettuce plants as compared with control treatment which recorded significantly increased in head diameter, head fresh weight, head dry weight and yield / fed, chemical composition i.e.

(N, P, K, Ca, Mg and Na), total carbohydrates percentage and vitamin C content during both seasons.