Abstract:The effects of soil fertility, soil moisture content and shade density on flowering and seed setting of Mikania microtha were investigated at different habitats in Dongguan City, Guangdong Province, during 2001 to 2002. The plants growing on less fertile soil caused fewer flowers, lower seed setting percentage, less 1000-grain weight and shorter flowering duration than those on more fertile soil. However, over-fertile soil also resulted in fewer flowers and low seed setting percentage. The plants growing in open habitat had more flowers with longer flowering duration, whereas under shade the 1000-grain weight was shown to have a slight increase. The seed setting percentage was highest at 10%-20% of shade density. Moist soil had no significant effect on 1000-grain weight, but obviously led to more flowers, high seed setting percentage and longer flowering duration.The effects of soil fertility, soil moisture content and shade density on flowering and seed setting of Mikania microtha were investigated at different habitats in Dongguan City, Guangdong Province, during 2001 to 2002. The plants growing on less fertile soil caused fewer flowers, lower seed setting percentage, less 1000-grain weight and shorter flowering duration than those on more fertile soil. However, over-fertile soil also resulted in fewer flowers and low seed setting percentage. The plants growing in open habitat had more flowers with longer flowering duration, whereas under shade the 1000-grain weight was shown to have a slight increase. The seed setting percentage was highest at 10%-20% of shade density. Moist soil had no significant effect on 1000-grain weight, but obviously led to more flowers, high seed setting percentage and longer flowering duration.