Abstract:

Survey was conducted by sampling methods of inverted W-pattern to the weed communities of leafy vegetable fields in Guangzhou region across 2008.The result showed 60 species were found, which belonged to 23 families,45genera.Weed communities were mainly consisted of Portulaca oleracea + stellaria media + Polygonum plebeium in spring; Portulaca oleracea + Cyperus iria + Amaranthus lividus in summer; Portulaca oleracea + Amaranthus lividus + Echinochloa colonum in autumn and Polygonum plebeium + stellaria media + Polygonum lapathifolium in winter.10 worst weeds were gotten by calculating the dominance of weeds and they were Portulaca oleracea, stellaria media, Polygonum plebeium, Polygonum lapathifolium, Amaranthus lividus, Cyperus iria, Digitaria sanguinalis, Eleusine indica, Echinochloa colonum, Cardamine hirsute. Portulaca oleracea, Amaranthus lividus, Cyperus iria were the dominant weeds in spring, summer and autumn; Digitaria sanguinalis was the dominant weed in summer, autumn and winter; Echinochloa colonum, Eleusine indica were the dominant weeds in spring and autumn; stellaria media, Polygonum plebeium, Polygonum lapathifolium, Cardamine hirsute were the dominant weeds in winter and spring.