Species composition and characterization of weed community in rice fields in Hubei Province

Weed survey was conducted by inverted W-pattern to determine the species composition and structure of weed communities in rice fields in Hubei Province in China.The results showed that 138 weed species(including varieties) belonging to 46 families and 94 genera were found.Among them,6 species were considered as worst weeds,including Echinochloa crusgall,Monochoria vaginalis,Leptochloac hinensis,Eclipta prostrata,Alternanthera philoxeroides and Cyperus difformis;11 species were regional worst weeds;24 were common weed species and 97 were normal weed species.The worst weeds were the main components of weed communities in all rice regions in Hubei,the typical weed communities were E.crusgalli+E.prostrata+A.philoxeroides,E.crusgalli+L.chinensis+E.prostrata,and E.crusgalli+M.vaginalis+C.difformis.The richness and diversity species of weed community in paddy rice fields in North Hubei region were higher than other regions,but the evenness index of Central-east Hubei region were relatively lower.Based on the Sorensen′s similarity index,the structure of weed community in North Hubei region was more similar to that of the overall communities in Hubei.The difference of weed occurrence and community structure might result from the cropping system,tillage type and environmental conditions.