A high variation in the diversity of weed was found across the studied paddy field types. Mid-elevation paddy field is highly diverse in weeds than lowland paddy field. Results show that altitude as well as water availability may support species richness. Poaceae, followed by Asteraceae, were most common. Some effects differed between regions correlated with different agricultural management, such as weeding habits, plant cropping and cultivation time. However, environment complexity by semi natural vegetation did not influence weed number in paddy fields. Accordingly, weed biomass and...