Allelopathy is a biological phenomenon that can be used to reduce weed growth by using crops that have an allopathic effect. Therefore, we have been determined to investigate the impact of licorice (Glycyrrhiza glabra L.) aqueous extract spraying on wheat, barley, cephalaria, and white mustard plants on chlorophyll content and biological yield in the plastic house from December 30th, 2024, to April 24th, 2025, at Grdarasha Research Field, College of Agricultural Engineering Sciences. For the aqueous extracts, five concentrations were used: 0,25,50,75, and 100%, with three replicates and a completely randomized design (CRD) used. Finding significant differences between plant species for all parameters, the aqueous extract at 50 and 75% concentrations gives the highest weed control efficiency in this study. Also, for the interaction between treatments, they found that chlorophyll content significantly increased in white mustard at 50%, 75%, and 100% licorice root extract.  Biological yield recorded the highest production in wheat, with 25%. The response ratio significantly increased in the Cephalaria plant to 67.85% from 100% and decreased in white mustard by 67.58% to 50%. In contrast, the inhibition ratio significantly increases to 64.58% for white mustard and 50%, and this rate is a 64.58% decline in cephalaria plants with 100% licorice extract. A laboratory experiment using a completely randomized design with four replicates was conducted at the same college to evaluate the germination and viability parameters of plant seeds and radicle and plumule characteristics. Findings showed that wheat and barley seeds were more resistant to licorice root extract than either weed seed. As licorice root aqueous extract concentrations increased from 25 to 100%, the inhibitory effect of allelopathic materials for all germination parameters was increased. The interaction between treatments gave the number (0.00) for all parameters studied by the white mustard plant and 100% licorice root extract