Phytochemical‐Mediated Allelopathic Activity of <i>Artemisia campestris</i> on Germination and Growth of Oasis Weed Species

The allelopathic potential of Artemisia campestris aqueous extract was evaluated against three weed species (Setaria verticillata, Phragmites communis, Cynanchum acutum) and two cultivated crops (Cucumis sativus, Capsicum annuum). Bioassays were conducted on seedlings in Petri dishes and on plants in pots using both foliar pulverization and soil incorporation to assess morphological and germination parameters. The extract induced significant inhibitory effects on weeds, particularly at higher concentrations. At 20 g/L, the germination rate of S. verticillata decreased by 89.2% and the germination index by 95.07%, while mean germination time increased to 4.9 days. Root growth was strongly suppressed, with inhibition rates of 77.3% in S. verticillata, 51.3% in C. acutum, and 25% in P. communis. Shoot growth was also reduced, with C. acutum exhibiting the greatest inhibition (20.01%). Foliar application at 0.2 g/mL decreased leaf number by 86% in S. verticillata, whereas crop species showed minimal sensitivity and even stimulated root development. Soil incorporation caused complete mortality of weed seedlings at concentrations ≥0.6%. These phytotoxic effects are consistent with the extract's high phenolic content, notably 1,3-di-O-caffeoylquinic acid (5368.39 ppm). Overall, the results demonstrate that A. campestris exhibits strong selective phytotoxicity and may represent a promising bioherbicide candidate for sustainable weed management.