IRAQI JOURNAL OF DESERT STUDIES

Abstract

The study was conducted during the growing season 2007-2008 to investigate the effect of soil mulching with
black polyethylene and foliar application of some natural plant extracts , i.e., Licorice at concentrations of ( 0.0 ,
1.5 and 3.0 gl-1) and seaweed extract " Algamix " from the marine algae Ascophyllum nodosum at concentrations
of ( 0.0 , 1.0 , 2.0 and 3.0 cm3 l-1 ) . Licorice extracts were sprayed 4 times (monthly intervals ) , while Algamix
was sprayed 7 times during the experiment (two weeks intervals) .
The treatments were arranged within split plots in a factorial R.C.B. Design, Planting methods were considered
as the main plots and the interactions between licorice and seaweed extracts were arranges in subplots with three
replications for each treatment . The results showed that mulching method with foliar spraying of Licorice and
Algamix extracts at concentrations of 3.0 gl-1 , 3.0 cm3l -1 respectively was superior significantly in their effects
on the vegetative growth , i.e., weight of fresh stem , stem length , fresh and dry weight of plant leaves without
stem. Increasing the head weight and total yield plant-1 by application of soil mulching with foliar spraying of
Licorice and Algamix. Significant increase was occurred in nitrogen , phosphorus and potassium percentages of
plant leaves as a result of mulching with high concentrations of Licorice and Algamix extracts. Existence of
high positive correlations between the total yield plant-1 with all studied traits with exception in flowering %.
Head weight and leaf area distinguished with highest direct effect on the total yield per plant, whereas, leaf area
and plant length had a highest indirect effects on the yield through path of head weight trait.