Three-year field survey (1993–95) and two-year field experiments (1993–94) on ecology of Echinochloa spp. revealed that all the three Echinochloa species i. e. E. colona, E. glabrescens and E. crusgalli preferred moist conditions and continued to grow under shallow submerged conditions. Among the three, E. crusgalli and E. glabrescens had stouter culms and attained greater height. The panicles were small in case of E. colona and arrangement of spikelets on panicle was in four rows, whereas irregular arrangement was noticed in other two species. The stigma colour of E. colona was blackish purple while white in other species. High crop density (44 hills/m2) had a discernible effect in reducing the tillers, biomass production of all Echinochloa spp. but it was more conspicuous in case of E. colona. In closer spacing, the decline in seed production was 67, 56 and 50% in E. colona, E. glabrescens and E. crusgalli, respectively. Nitrogen fertilization had a pronounced positive effect on the growth of Echinochloa spp.
