Effect of spraying humic acid and potassium fertilization on growth and yield of lettuce plant Lsuctuca Sativa L

Abstract

A field experiment was conducted in  season 2019-2020 to study the effect of different levels  fertilization using humic acid and potassium on the growth of  lettuce plant. The experiment was conducted according to Complete Randomized Blocks Design(RCBD) and with two factors: the first is the ground fertilization factor using compound fertilization with levels of 200, 100 and 50 kg /ha and the second factor is foliar fertilization with humic acid with three concentrations (50, 25 and 12.5 ppm).  The results showed  increased in  root length, wet, dry weight and chlorophyll content  with higher values reached (16.1 and 16.7 / g), (97.7 and 101.1 / cm) ,(11.9 and 10.6 / g) and (76.52 and 70) using treatment  200 kg / ha  potassium and 50 ppm humic acid respectively. While the lowest rates were recorded with control treatment for all treatment. Vegetative characteristics recorded same response for  fertilization with level of 200 kg / ha and 50 ppm, the highest averages for stem length, leaf area, head diameter, head weight and head diameter with values (44.5 and 47.7), (8114 and 7255), (72.4 and 67.5), (1123 and 3.781) and (4.72 and 5.67) / cm