Phyto-sociological Studies of Rainy Season Weeds with Special Reference to Imperata cylindrica (L.) Raeuchi in Godavari Delta

A phyto-sociological survey was conducted in Godavari delta of Andhra Pradesh during kharif 1994 to 1996. The data revealed that about 38 weed species were found associated with Imperata cylindrica during rainy season. Among all weeds, I. cylindrica, Cynodon dactylon and Cyperus rotundus had high degree of sociability and formed into large colonies under arable soil habitats. The weeds C. rotundus, Croton, sparciflorus and Amaranthus spinosus recorded higher importance values and were found dominant under road side situations. Under field bund conditions, I. cylindrica, Brachiaria mutim and Eleusine indica had relatively more dominance due to their high frequency and density. I. cylindrica proved to be highly dominant due to its maximum relative density and frequency followed by Merrimea emerginata and Parthenium hysterophorus under wasteland agro-ecosystem. Under saturated soil conditions, some hydrophytes such as Ipomoea aquatica, Ipomoea carnea and Polygonum barbatum dominated the habitat due to their adoptation under marshy environment.