PHYTO-SOCIOLOGICAL SURVEY OF WEEDS IN DIRECT SEEDEDRICE (ORYZA SATIVA L.)R. Suganya, S.M. Suresh Kumar and G. Baradhan
Field observation was carried out at Melbhuvanagiri block, (Valayamadevi, Periyanarkunam, AgaraAlambadi and Periyakuppam villages), Cuddalore district during 2020 to determine the phytosociologicalcharacters of weeds in direct seeded rice fields. The composition of the weed species in the fields wasevaluated by randomly throwing 0.25 m2 quadrate in 10 different locations in each village. Frequency,density, abundance and their relative values were calculated. Highest relative frequency, relative density,relative abundance and importance value index was observed with Echinochloacolona (L.)Link amonggrasses, Cyperus difformisL. among sedges and Eclipta alba (L.) Hassk among broad leaved weeds in all theobserved villages of direct seeded rice fields. Diversity indices were worked out for each village, amongthem Periyanarkunam village recorded the highest diversity indices (Shannon index (Hâ) of 2.234, Simpsonindex (D) of 0.873 and Evenness index (E) of 2.070) in direct seeded rice. Hence weeds were prominent inPeriyanarkunam village than all the observation sites.